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HomeMy WebLinkAboutAPA414SUSITINA HYDROELECTRIC PROJECT PHASE I FINAL·REPORT Sterling D.Miller Dennis C.McAllister ALASKA OEPARTMENT OF FISH ANO GAME Submitted to the Alaska Power Authority March 1982 ..~ .- PREFACE In early 1980,the Alaska Department of Fish and Game contracted with the Alaska Power Authority to collect information useful in assessing the impacts of the proposed Susitna Hydroelectric Project-on moose, caribou,wolf,wolverine,black bear,brown bear and Da11 sheep.This information,along with information on furbearers,small mammals,birds, and plant ecology collected by the University of Alaska,is to be used by Terrestrial Environmental Specialists,Inc.of Phoenix,New York,in preparation of exhibits for the Alaska ,Power Authority's application for a Federal Energy Regulatory Commission license to construct the project. The studies were broken into phases which-conformed ~o the anticipated licensing schedule.Phase I studies,January 1,1980 to June 30,1982, were intended to provide information needed to support a FERC license application.If the decision is made to submit the application,studies will continue into Phase II to provide additional information during the anticipated 2 to 3 year period between application and final FERC approval of the license. Wildlife studies did not fit well into this schedule.Data collection could not start until early spring 1980,and had to be terminated during fall 1981 to ,allow for analysis and report writing.(Data continued to be collected during winter 1981-82,but could not be included in the Phase I report.) The design of the hydroelectric project had not been determined.Little data was available on wildlife use of the immediate project area,although some species had been intensively studied nearby.Consequently,it was necessary to start with fairly general studies of wildlife populations to determine how each species used the area and identify potential impact mechanisms.This was the thrust of the Phase I Big Game Studies.During Phase II,we expect to narrow the focus of our studies to evaluate specific impact mechanisms,quantify impacts and evaluate mitigation measures. Therefore,the Final Phase I Report is not intended as a complete assessment of the impacts of the Susitna Hydroelectric Project on big game. The reports are organized into the following eight volumes: Volume I. Volume II. Volume III. Volume IV. Volume V. Volume VI. Volume VII.. Volume VIII. Big Game Summary Report Moose -Downstream Moose -Upstream Caribou Wolf Black Bear and Brown Bear .,Wo1 verine 't,..pall Sheep ARLIS Alaska Resources Library &Informaij,on Services JUlchorage,AJaska .... -. - - - "... SUSITNA HYDROELECTRIC PROJECT FINAL PHASE I REPORT BIG GAME STUDIES Volume VI BLACK BEAR AND BROWN BEAR Sterling D.Miller and Dennis C.McAllister ALASKA D~PARTMENT OF FISH AND GAME Submi t ted to the Alaska Power Authori ty March 1982 fk I~:15 11'6 fb ~v Y\ol~l~ ARLIS Alaska Resources Library &Information Services Anchorage,Alaska - I.SUMMARY OF PERTINENT FINDINGS-BEAR STUDIES Projected impacts of proposed hydroelectric development on upper Susitna River populations of brown and black bears were investi- gated in 1980 and 1981.The preliminary investigations for Phase I of the impact assessment that are reported here were designed to reveal the kinds of impacts which might result from the pro- posed project l quantitative assessments of actual impacts were l ir.L most cases l postponed until Phase II of the assessment studies sc:heduled to begin in 1982. In Phase I a sample of both species was radio-collared and peri- odically monitored in order to identify the patterns of use of a:t'eas that would be impacted by the proposed project.This ana1- YSiis was based primarily on a total of 518 brown bear and 724 black bear locations 'in the study area,collected between April 1980 and October 1981 for black bears and between April 1980 and 1 September 1981 for brown bears.These termination dates re- present analytical deadlines l data collected.subsequently are bedng analyzed. The sample of radio-collared adult brown bears was considered re:presentative in terms of age structure but biased against ma.les.In compari son with other North American brown bear popu- la.tions l t~e study area population appeared highly productive and moderately dense.An estimate of 1 bear/41-62 km 2 1 obtained in 1979 in a nearby study area,was considered the best available approximation of brown bear densi ty in the study area. Brown bear harvests by hunters ;have averaged 64/year in 1973-1980 in Game Management Unit 13 (range 44-84L lS/year in the project study area (9-24 ) .Improved access and increased human populat- ions during proj ect construction and operation are expected to resul t in substantially increased hunting effort and harvest. Th.e mean elevation of 29 brown bear den sites was 4 1 818 feet i (range=2330-5150 feet).No brown bear den discovered to date would be inundated by the proposed impoundments but some were in areas where disturbance during project construction or operation could resul t in abandonment or avoidance of den si tes" Brown bear home ranges were highly variable between individuals and years.The mean home range of 11 bears in 1980 was 422 km 2 , 487 km 2 in 1981.Home range sizes varied from 50-2655 km 2 • Larger home ranges in 1981 relative to 1980 may have resulted from a relatively'poor berry crop in 1981.Brown bears captured along the Susi tna River ranged over a total area of 8,473 km 2 • This represents 'a minimum estimate of the area in which brown bears would be affected by the proposed impoundments. The period of peak use of areas directly impacted by the proposed impoundments was in spring and early summer.During this period 62%of radio-collared brown bears were located within 1 mile of the proposed impoundment in 1981,50%in 1980 (excludes females wi th newborn offspring).In both years 30%of all observations of these bears were within this,conservatively defined,impound- ment impact zone.We suspect that brown bears tend to move to lower elevations near or in the impoundments in early spring be- cause of the relatively earlier availability of vegetable forage in these areas;prey,especially moose calves,may also be more available in this impoundment impact area.This pattern was not followed by females with newborn cubs,these bears tended to remain at high elevations away from the'impoundments.Perhaps this avoidance of areas where other bears concentrate is adaptive in minimizing intraspecific predation on their cubs. This same pattern was verified by statistical analyses of loca- tions of brown bears within 3 nested regions of the study area: The actual impoundment,within 1 mile of the impoundment shore- line,and 1-5 miles from the shoreline.Here observed use in the actual impoundment area was greater than would have been expected ii ..... i -, i, ..... ..... - on the basis of the relative size of the impoundment area.This difference was especially marked in the spring when observed use was 4 times greater than expected under the null hypothesis of no -selectivity. ~nis same pattern was evident in analyses of the habitats where rlelocated brown bears were found.Use of spruce habitats which occur primarily in the vicinity of the impoundments was significantly higher in the spring than during the rest of the ,.... Data on availability of different vegetation types based on the t:~e maps prepared by the Plant Ecology Subtask were not parti tioned in a way that would permit meaningful analyses of selectivi ty of these different vegetation types for the area mapped at the 1:63,360 scale.Appropriate partitioning of these diata were available for the actual area that would be flooded by the proposed impoundments,however.Analyses of these data suggested that brown bears tended to select for mixed ccmifer-deciduous forest types in the Watana impoundment area. - Brown bear movements to areas of seasonally reoccurring food abundance may be blocked or inhibited by the proposed impound- ments.Such movements may include movements to Prairie Creek or downstream along the Susi tna to fish for salmon (both have been documented),or movements to moose or caribou concentration areas such as calving grounds (movements to caribou concentrations were also documented).Movements to Prairie Creek by bears from an area of 5,773 km2 were documented in this study,these movements rE~quired crossing the impoundments and the proposed access roads. Brown bear predation rates were intensively monitored (once/day) in spring 1981.A kill rate of 1/10.2 days was observed,sub- s1tantially lower than has been recorded in more intensive studies conducted in 1978 in nearby areas.The observed kill·rate was suspected to be biased because of relatively infrequent moni- iii toring and reLatively poorer visabili ty caused by more dense vegetation in the study area. More accurate data on predator-prey relationships based on in- tensive monitoring of radio-collared moose and caribou calves are proposed for Phase I I of these investigations.More intensive brown bear food habits studies based on feces analysis are also proposed for Phase II,these studies should concentrate on spring and early summer uses of impoundment-impact areas. ~.j ~ A summary of expected impacts on brown bear populations caused by the proposed impoundments include:1.Reduction of habitat,es- pecially habitats used selectively in spring and early summer;2. Increased human presence which would result in increased hunting, defense of life and property kills,and disturbance;3.Inhibi- tion or blockage of seasonal movements to areas of food·concen- tration;4.Disturbance of den sites;5.Indirect impacts through reduction of availability of important prey items in- cluding moose,caribou,and downstream salmon;and 6.Climatic changes which alter the availability or abundance of food resources,especially early in the spring. The sample of radio-collared adult black bears was considered representative in terms of sex ratio and age structure.In com- parisonwith other North American black bear pop~lations,black bears in the study area appeared to be productive although pos- sibly having an older age of reproductive maturity and higher rate of cub mortality than an intensively studied population on the Kenai Peninsula.No good density estimate was obtained for the study area although a rough estimate of 1 bear/4.1 km 2 was obtained in one relatively open area based on aerial observations of marked and unmarked bears. Black bear harvests have averaged 66/year in 1973-1980 in Game Management Unit 13 (range=48-85 ) ,8/year in the project study iv - - ...., - area (1-15).Improved access and increased human population during project construction and operation are expected to result in substantially increased hunting effort and harvests.These changes alone could easily eliminate black bears resident in the h:ighly constricted post-impoundment forested habitat remaining in the vicini ty of the upper impoundment. Fourteen black bear den sites used in 1980/81 were located and ml~asured,an additional 19 dens being used in 1981/82 have been tl~ntatively·located from the air.All but one den was below 3,000 feet elevation,most were in the immediate vicinity of the proposed impoundments.Of 13 dens found in the vicinity of the proposed Watana impoundment,9 will be flooded at an impoundment elevation of 2,200 feet,the mean elevation of these dens was 2,177 feet (1,800-2,750 feet).In the vicinity of the proposed DE~vils Canyon impoundment,·1 of 16 known dens would be flooded Oat all impoundment elevation of 1450 feet,the mean elevation of these dens was 2,178 feet (1490-4340 feet).A higher proportion of black bears in the study area den in natural cavities and re- use den sites than has been recorded in other Alaskan studies suggesting relative scarcity and competition for acceptable den s:L tes in the study area.The impact of the Watana impoundment on black bear denningareas is expected to be severe,based on these data.Much less impact is expected for the Devils Canyon im- poundment. Black bear home ranges were significantly larger in 1981 (mean= 2S1 km2 ,range=19-1051)than in 1980 (mean=31 km2 ,range=3-136). We suspect the increased movements observed in 1981 reflect,for the most part,the relatively poor berry crop which forced bears to move greater di stances in search of forage.The total area encompassed by movements of radio-collared black bears was 4,196 klIrl 2 i much of this area .away from the river was considered unac- cE~ptable or poor black bear habi tat. v Acceptable black bear habitat in the study area was largely con- fined to a narrow finger of forested habitat along the Susi tna River;these are the areas which will be the most impacted by the proposed impoundments.In late summer many black bears moved to shrubland habitats adjacent to these spruce forests to forage for ripening berries,generally returning to the forested habitats to den in September.Such shrubland habitats that are also adjacent to forested escape habitat are limited in extent and would be impacted by construction facilities (such as the current site of '-1\ Watana Camp),borrow areas D and F,and access roads. Analysis of the location data within the 3 nested zones of the study area (impoundment area,1 mile from impoundment shoreline, and 1-5 miles from the shoreline)revealed exceptionally high selectivity by black bears.In the area that would be flooded by the proposed Watana impoundment,black bear use was 2-4 times higher than expected based on the relative area of this zone,use was also higher than expected in the zone 1 mile from the impoundment shoreline.For the Devils Canyon impoundment ob- served use exceeded expected values in the area wi thin 1 mile of the impoundment shoreline.These analyses verify that each impoundment would have a major direct impact on habitats used by black bears,and that this impact would be much more severe in the vicinity of the upper impoundment than in the vicinity of the lower impoundment. Analyses of selectivity for the different vegetation types mapped at the 1:63,360 scale by the Plant Ecology Subtask could not be accomplished as discussed for brown bear.However,as for brown bear,such analyses were possible in the area that would actually be flooded by the Watana Impoundment.Here use varied signifi- cantly from values expected under the hypothesis that black bears were randomly using all vegetation types.Open birch and closed birch habitats appeared to be the most favored types.A high proportion of these 2 vegetative types would be inundated by the proposed impoundments. vi - ""'" - Three radio-collared black bears moved downstream below the Devils Canyon damsite in 1981.These movements were suspected to be motivated by spawning salmon in this region.It is not known whether these movements occur also in years of normal berry pro- duction.However,dam-related changes in the abundance of salmon downstream of Devils Canyon would impact these bears as well as black and brown bears that are resident in this area.Given the probabi li ty of maj or impacts on spawning salmon downstream of Dlevils Canyon,downstream bear studies are needed in Phase II of impact assessment studies. A:s discussed for brown bears,relatively low predation rates by black bear on moose calves were observed.Biases resulting from n~latively infrequent monitoring and poor sightability of kills are expected to account for the low observed'predation rates. Predation rate studies based on radio-collared calves are needed in Phase II to document the indirect effects of reduction of moose and,perhaps,caribou populations on black and brown bears. Black bear food habits studies based on fecal analysis are also ne~eded in Phase I I . A summary of expected impacts on black bear populations caused by the proposed impoundments include:1.Inundation of scarce denning habitats (especially in the upper impoundment area),2. Halbi tat elimination through inundation,3.Increased human dis-.- turbance and hunting resulting from project construction,oper- at:ion,and improved access,4.Increased predation by brown .- beiars resulting from decreased availability of berry-rich shrub- .lands which are also adj acent to forested escape habitat,6. Reduction of prey items (downstream salmon,moose calves and, pe:rhaps,caribou),7.Impoundment related climatic changes which al ter the availabili ty or abundance of food resources. vii .""" I. II. III. IV. V. VI. VII. VIII. . I I.TABLE OF CONTENTS Summary of Pertinent Findings Table of Contents List .of Tables Li st of Figures Introduction and Acknowledgements Methodology The Study Area Results and Discussion-Brown Bears Page No. i viii xi xvi 1 7 14 15 A. B. C. D. E. Sex and Age Composition of Study Animals-Brown Bear Sport Harvest-Brown Bear Population Biology and Productivi ty- Brown Bear Population Densi ty-Brown Bear Home Range Analyses-Brown Bear 1.Home Range s 2.Movements to Fi shing or Hunting Sites 3.Di spersal 4.Seasonal Use of Impoundment Impact Areas 5.Proximity Analysis 6.Impact of Borrow Areas viii 15 18 27 35 37 37 50 54 55 58 60 TABLE OF CONTENTS (cont'd)Page No. F. G. Habitat Relationships-Brown Bear 1.Aerial Classifications 2.Vegetation Map Classifications Den and Denning Characteristics- Brown Bear Predation Rates-Brown Bear 60 60 63 67 76 IX..Resul ts and Di scussion-Black Bear 78 - ~~~~_~__._._..~.A..__Sexan<:tAge_Composi tion of Study Animals-Black Bear B.Sport Harvest-Black Bear C.Population Biology and Productivi ty- Black Bear D.Population Densi ty-Black Bear E.Home Range Analyses·-Black Bear 1 .Home Range s 2.Seasonal Movements 3.Proximity Analysis 4.Dispersal 5.Impact of Barrow Areas F.Habitat Relationships-Black Bear 1.Aerial Classifications 2.Vegetation Map Classifications G.Den and Denning Characteristics- Black Bear H.Predation Rates-Black Bear 78 81 88 92 95 95 103 107 109 112 113 113 115 118 123 ~, x.Summary of Pro j ect Impacts on Bear Populations A.Brown bear B.Black bear ix 127 127 129 TABLE OF CONTENTS (c:ont'd)Page No. XI. XII. Phase II Study Needs and Objectives References 136 143 XIII.Appendices l.Di stribution Maps for Individual Brown Bears 152 2.Di stribution Maps for Individual ~Black Bears 174 3.Brown Bear Densi ty Paper Submitted to Can.Field Naturalist (Miller and Ballard)204 4.Abstract of Brown Bear Home Range PCl-per accepted by Can.Field Naturalist (Ballard et a1.)221 5.Prince William Sound Den Study (Miller et al.1981)222 ~6.Feces Identification Techniques (Goodwin and Miller)230 x •'"t\ - ,~ 1. 2. 3 . 4. s. 6. 7. 8. 9. 10. 11. 12. 13. I I I.LIST OF TABLES Chronological list of brown bears captured Number of brown bear radio relocation Sex and age composition of captured brown bears Mean age of Susi tna-area brown bear subpopulations Uni t 13 brown bear harvests Brown bear sport harvests in proj ect area Comparisons of brown bear litter sizes in different studies Survivorship and weaning of brown bear offspring Compari sons of brown bear reproductive rates Brown bear reproductive intervals Annual production of brown bear litters I 1978-1981 Reported brown bear densi ties in North America Home range sizes for study-area brown bears xi Page No. 19 21 22 23 24 26 28 29 31 32 36 38 39 LIST OF TABLES (cont 1 d)Page No. 14.Comparisons of brown bear mean home ranges in 1978,1980,and 1981 15.Statistical comparisons between brown bear home ranges in 1978, 1980,and 1981 41 ....., II I -, 42 16.Compari sons of brown bear home ranges in different studies 44 17.Mean elevation of b-lack-&-brOWfrcbe-a-r~--~-­ relocations xii 46 (cont'd) 24. 25. 26. 27. 28. 29. 30. 31. 32. 33. 34. 35. LIST OF TABLES Brown bear den site characteristics Di stances between brown bear dens used by individual bears in 1980/81 and 1982 comparIsons of brown bear den entrance and emergence dates in 1980/81 and 1981/82 Time spent in 1980/81 dens by black bears and brown bears Brown bear predation rates in 1978 and present study Intensi vely moni tored black and brown bear predation rates Chronological Ii st of black bears captured Number of black bear radio relocations Mean age of black bear subpopulations in Susi tna area and on-the Kenai Peninsula Sex and age composition of captured black bears Uni t 13 black bear harvests Black bear sport harvests in project area xiii Page No. 69 73 74 75 77 79 80 82 83 84 86 87 LIST OF TABLES (cont'd)Page No. """" 36. 37. 38. 39. 40. 41. 42. 43. 44. Survivorship and weaning of black bear offspring Black bear reproductive intervals Comparison of black bear densities in different studies Home range sizes for study-area black bears Comparisons of black bear mean home ranges in 1980 and 1981 Statistical comparisons between 1980 and 1981 mean black bear home ranges Overlap of black bear home ranges wi th impoundment polygons Black Bear Use of nested impoundment proximi ty polygons Black bear habitat use based on aerial classifications of habitat 89 91 94 96 98 99 101 108 114 45a.Black bear hcibi tat se1ectivi ty data in whole study area 45b.Black bear vegetation type se1ectivi ty analysis in impoundment area xiv 116 117 ~ LIST OF TABLES ~. (c:ont'd)Page No. 46.Black bear den site characteristics 119 47.Di stances between black bear dens used in 1980/81 and 1981/82 120 ~·f 48.Black bear den entrance and emergence dates 125 ~49.Compari son of black bear den entrance dates in 1980-81 and 1981/82 126 .... .... - xv IV.LIST OF FIGURES .Fig.1.Brown bear study area Fig.2.Black bear study area Fig.3.Illustration of 1 and 5 mi Ie polygons surrounding the proposed Su-Hydro Impoundments Fig.4.Home ranges of brown bears that fish at Prairie Creek Fig.5.Brown bear den sites in the Su-Hydro study area,1980/81 Fig.6.Aspect of brown bear den sites in the Su-Hydro study area,1980/81 Page No. 16 17 49 51 70 71 Fig.7.Location of black bears in late summer illustrating use of shrublands adj acent to spruce forests 104 Fig.8.Black bear den si tes in the Su-Hydro study area,1980/81 and 1981/82 121 Fig.9.Aspect of black bear den sites in the SU~Hydro study.area,1980/81 124 Appendix 1.Brown bear home range maps. Fig.10.Composite of all brown bear home ranges 153 - Fig.11.Location of all unmarked brown bears observed,1980-1981 xvi 154 LIST OF FIGURES (cont'd)Page No. Fig.12.Point locations and home range for brown bear 214 155 - Fig.13.Point locations and home range ~, for brown bear 277 156 Fig.14.Point locations and home range for brown bear 280 157 - Fig.15.Point locations and home range for brown bear 281 158 ~ Fig.16.Point locations and home range ~ for brown bear 283 159 Fig.17.Point locations and home range for brown bear 293 160 Fig.18.Point locations and home range for brown bear 294 161 Fig.19.Point locations and home range for brown bear 299 162 ~ Fig.20.Point locations and home range for brown bear 308b 163 Fig.21.Point locations and home range for brown bear 312 164 Fig.22.Point locations and home range for brown bear 313 165 ~ xvii -i I xviii LI ST OF FIGURES (cont'd) Fig.44.Point locations and home range for black bear 318 Fig.45.Point locations and home range for black bear 315 Fig.46.Point locations and home range for black bear 321-- "~-~-~-----.-----~i~.~41_.---Pointlocati-<>ns-and home range for black bear 322 Fig.48.Point locations and home range for black bear 323 Fig.49.Point locations and home range for black bear 324 Fig.50.Point locations and home range for black bear 325 Fig.51.Point locations and home range for black bear 327 Fig.52.Point locations and home range for black bear 328 """ Fig.53.Point locations and home range for black bear 329 Fig.54.Point locations and home range for black bear 330 xx Page No. 188 189 190 191 192 193 194 195 196 197 198 LIST OF FIGURES - (cont'd)Page No. ~ Fig.55.Point locations and home range for black bear 342b 199 Fig.56.Point locations and home range for black bear 343 200 ~ Fig.57.Point locations and home range for black bear 346 201 Fig.58.Point locations and home range for black bear 348 202 Fig.59.Point locations and home range -I for black bear 349 203 - -! -xxi v.INTRODUCTION Black bear (Ursus amer;canus)and brown bear (U.arctos)are widely di stributed and abundant in Alaska.Black bear di stri- bution in Alaska coincides closely with the distribution of forests,with the most abundant populations occurring in "open" forests rather than heavy timber;extensive open areas are usu- ally avoided.Brown bears seem best adapted to open areas of tundra or grasslands although,like black bears,they inhabit a variety 9f different habi tats in Alaska. Taxonomically there is only oz:.e species of brown-grizzly bear. In common usage the term brown bear is utilized to refer to sQuthern----a-nd-~Gastal--popu_±_a'ti-ens--o;£this species -and-grizzly bear rlefers to northern and interior populations.Typically "brown" blears are larger and darker than "grizzly"bears.The brown- grizzly bears along the Susi tna River described in thi s report are,most appropriately,referred to as brown bears. Black bears in Alaska tend to be smaller than in many areas of the contiguous United States,adults commonly weigh 100-200 Ibs. S.everal color phases of black bears are known,the Susi tna popu- lation includes individuals that are black,cinnamon,and dark brown. In Alaska,both species of bears spend the winter in dens.Black blears use a variety of densi tes including excavations on hillsides or under logs and trees and natural cavities in rock- piles,caves or hollow trees.Brown bears most commonly den in wl:!ll excavated holes on high mountain slopes.The denning period fc:>r both species typically runs from October through April or May but annual,geographic,and individual variations are common.In the Susitna area available observations suggest that black bears enter dens earlier and emerge later than brown bears. 1 Brown bears are more aggressive and dangerous to man than black bears,this may be the result of evolution in a more open envi- ronment without trees to serve as escape habitat and the corre- sponding need for more aggressive behavior to protect themselves and their offspring (Herrero 1972).The corresponding danger to man combined with the increased vulnerability to hunting associa- ted with more open habitats,has led to great reductions in brown bear distribution and abundance in the contiguous United States. Except in Alaska and parts of Canada,the species is currently classified as endangered.Black bears,on the other hand,are still abundant throughout most of their original range. Both species have evolved generalist and opportunist strategies and are,correspondingly,biologically compatible with many kinds of man-caused disturbances of their habitat.However,experience has amply demonstrated that brown bear abundance is usually in- compatible with increasing human presence except in a few parks where bears are given a legal priority over human developmental activities.Both species of bears are omnivorous,eating a wide variety of grasses,sedges,other herbaceous plants,roots and berries as well as animal protein when available.Populations wi th access to salmon may heavily utilize this resource during portions of the year.Brown bears have recently been shown to be significant predators on moose calves in the upper Susi tna-Nelchina Basin area (Ballard et al.1980). Brown bear research has been undertaken since 1978"in the Nelchina and Susi tna River Basins.This research has concen- trated on the magnitude and effects of brown bear predation on moose but considerable life history data were also collected (Ballard et al.1980,Spraker et al.1981).In this region, federal predator control,programs conducted from 1948 to 1953 are suspected to have reduced bear populations to low levels. In the last 20 years brown bear populations have increased and the current population appears to be abundant,young and pro- 2 - -, """!I, - ~ I du.ctive.Fall harvests in the period 1973-1980 averaged 64 bears/year (30-84 bears/year)in Alaska I s Game Management Unit (GMU)13.This.level of harvest is suspected to be less than the maximum sustainable yield of this population.In 1980 and 1981 a May 10-25 bear season was held in addition to the normal 1 Sept. -31 Oct.season.In 1982 the spring season will be extended to 2.5 April -25 May. The abundance of black bears and relatively light hunting pres- sure in these areas permits a year-long open hunting season and an annual bag limit of three bears.An annual average of 66 black bears have been taken in GMU 13 from 1973-1980 (58-85 bears/year).Relative to brown bears,black bears'are more pro- ductive and this populationc..Qul~$.uptain_hi2her..~eve.ls .0£har~ vlest.Black bear research has not been previously conducted in the Susi tna or Nelchina River Basins.The only ongoing Alaskan black bear research project is on the Kenai Peninsula,this pro- jlect is being conducted by C.Schwartz (ADF&G).A Forest Service black bear denning project in southeastern Alaska is being conducted by A.Erickson (U.of Washington,Seattle). The overall obj ectives of black bear and brown bear mandated by proposed hydroelectric development on the River are: studies Susitna "To determine the di stribution and abundance of black and brown bears in the vicinity of proposed impoundment area;seasonal ranges,including denning areas,and movement patterns of bears;and seasonal habitat use of black and brown bears." In Phase I of these studies,emphasi s has been placed on deter- mination of relative abundance and seasonal di stribution of the t\flO species,in the vicinity of proposed impoundments,and on collection of baseline information on basic biology of irnpact- area bears in order to compare Susi tna-area populations with 3 populations elsewhere.With these kinds of data available l Phase II investigations can concentrate on quantification of the levels of potential impacts and on the reasons for them. 4 - - - ~I Acknowledgements Many individuals have contributed in meaningful ways to this study.Karl Schneider (ADF&G)deserves special mention for his help and support in the office and in the field.Other Su-Hydro project staff (ADF&G)also assisted in various ways including: W.Ballard,C.Gardner,J.Westlund,K.Pitcher,P.Arneson,R. Modafferi,J.Dau and S.Albert.Especially valuable assistance was provided by the Su-Hydro data processing,biometrics,and gleoprocessing staff:D.Anctil,S.Miller,and L.Van Daele. Danny Anctil,in particular,was important in his skillful and dedicated efforts to apply a new technology,geoprocessing,to our data.Important contributions were also made by other ADF&G staff including:S.Eide,J.Faro,C.Schwartz,E.Goodwin,L. Miller,L.Glenn,A.Franzmann,R.Tobey,T.Spraker,R.Kramer, H..Reynolds,M.Chihuly,P.Martin and'P.Mendes.Our office s1:aff (C.Reidner,L.Lewis,S.Lawler,P.Miles,and A.Fridman)..- were helpful in the preparation of these difficult reports.Karl Schneider and G.Bos (ADF&G)reviewed the manuscript.- '""'" - Our helicopter pilots (V.Lofstedt and C.Lofstedt)and fixed- wi.ng pilots (A.Lee,K.Bunch,B.Lofstedt,M.Hauke,D.Wilson, R.Halford,and C.Allen)deserve special mention for the safe, efficient and skillful services they provided.Additional assis- tance was provided by several helicopter pilots on contract to Acres at Watana camp.Two Fish and Wildlife Protection officers also assisted in 1980:Mike Mayberry and Dan Bunselmeier. Thanks go to the Denali Mining Company for allowing us to use their strip at Susitna Lodge and to Adventures Unlimited for fuel storage and accommodations. Numerous members of Acres and TES staff provided assistance in various ways;Granville Couey (Acres),the Watana Camp Manager, was especially cooperative.Dr.Richard D.Taber (TES consul- tant)provided many helpful suggestions and valuable advise. 5 The Department of Natural Resources (DNR)provided access to their geoprocessing hardware and software and assisted our staff in our data analysis chores on their computer.Additional equip- ment and geoprocessing support was provided by G.Cook and C. Barnhart of the Habitat Protection Section (ADE'&G). 'I 6 - VI.METHODOLOGY Brown and black bears were captured by procedures described in Spraker et al.(1981)'and Ballard et al.(1980).In brief, fixed-wing aircraft (PA-18)were used to search for bears and bears were immobilized from a helicopter (Bell 206B).Drugs utilized included Phencyclidine hydrochloride (Sernalyn), etorphine (M99)and its antagonist Diprenorphine (M50-50), Ketamine hydrochloride (Vetelar),and xylazine (Rompun). Standard morphological measurements were taken of immobilized bears.When terrain conditions permitted,weights were obtained by means of a scale suspended from the helicopter or a hand-held scale.Specimens of blood and hair were collected to assess physiological condition.Identifying marks applied to bears included:lip tattoos,ear tags,and ear flags.'In 1981 collared flags were attached to these radio-collarf!(red for males,white for females)and ear flags were not utilized. Individual bear numbers referred to in this report represent tattoo numbers preceded by a "G"for brown bear and a "B"for black bears. Bears judged to have completed 80 percent or more of their growth were fitted with radio-collars which transmit in the range of 148.0-153.9 MHz.Most transmitters had mortality sensors which halve the pulse rate when the collar is stationary for 2 hours, this permits recognition of when a collar has been shed or the bear is dead and also prolongs battery life by reducing electri- cal draw when bears are in dens. Bears were captured on 10 April-7 May and 18-19 August,1980 and on 5-9 May and 6-7 August,1981.Two yearling black bears accom- panied by their radio-collared mothers were captured and marked in their 1980/81 dens.The August tagging efforts were designed primarily to capture black bears on mid-summer habitats,away from their winter dens.These summer captures avoided den-site 7 selectivity biases which may have resulted-had only spring- captured bears been followed to their dens.A chronological list of all bears handled is presented in Tables 1 eSC 2. Attempts to locate radio-collared animals were made on approxi- mate 10 day intervals in 1980 and weekly in 1981.Actual flights varied from this schedule depending on weather conditions and aircraft availability.Most radio location flights were made in a Cessna 180 based in Anchorage and refueled at Susitna Lodge or Talkeetna.Flights in 1980 were made on:14,22 and 29 May,4, 12 and 23 June,2,10,18 and 22 July,4,14,22 and 27 August,9 and 29 September and 9,13,and 27 October.Flights in 1981 were made on:7 and 21 April,5-10,15,21 and 29 May,10,18 and 21-23 June,1,22 and 29 July,4,6-7,17 and 24 August,1,9,16 and 22 September,and 1,7,16 and 30 October.In addition,from 21 May -23 June 1981 daily monitoring was conducted of selected individuals to evaluate predation rates;the majority of these daily bear observations were co'llected concurrently with inten- sive monitoring of moose eSC wolves by Glennallen Su-Hydro staff (Ballard,Gardner and Westlund).Additional radio-locations were made in conjunction with flights to locate other species in the Susi tna study area.Reasonable efforts were made to visually observe all radio-located bears.The locations of all non-marked bears spotted during radio-location flights were also recorded. Locations were plotted on US Geological Survey maps (scale 1:63,360)and information on habitat type,behavior,associ- ations,topography,etc.were recorded. 8 ""'" - In 1980 the habitats in which bears were observed was recorded in .-the following 17 habi tat types: l. 2. 3. 4. 5. 6. 7. 8. 9. Sparse tall spruce Mod.tall spruce Mod.tall spruce (riparian) Sparse med.spruce Mod.med.spruce Dense med.spruce Sparse low spruce Mod.low spruce Dense low spruce 10 ..Riparian willow 11.Upland willow 12.Willow birch 13.Aspen 14.Ripari an hardwood 15.Marsh 16.Alder 17.Rock/ice In 1981 these habitat types were expanded to include: ~ I 18. 19. 20. 2l. 22 .. 23. Sedge-grass tundra Alpine herbaceous tundra Shrub tundra (mostly"dwarf birch,Betula nana) Mat &cushion tundra gravel bar Mixed sprucejbirch. This expansion of habitat-types was designed to coordinate class- ifications with the vegetation-type categories being utilized by the Su-Hydro vegetation analysis team from the U.of Alaska, Agricul tural Experimental Station.The tundra classifications utilized in 1981 would have been classified as upland willow or w:illow-birch in 1980. 9 Sufficient numbers of observations have not yet been collected to make all 23 of these classification-types meaningful.Therefore, for the gross comparisons of habitat use frequencies discussed in this report,these types were lumped as follows: SPRUCE:Types 1 -9, RIPARIAN:10,13,14,22,and 23, SHRUBLANDS:II,12, 16,and 20, TUNDRA:18,19,and 21,and OTHER:15 and 17. As mentioned above,the "tundra"categories were not used for the 1980 observations and will be underrepresented in the data pre- sented,especially since,for brown bears,the data are compiled only through 1 September 1981.The "other"category includes a few marsh observations but primarily represents observations on rock and ice.Habitat classifications were made from the air- craft for a total of 518 brown bear observations and 724 black bear observations.For 81 (16%)of the brown bear observations and 227(31%)of the black bear observations,2 habitat categories were recorded when the observation was made (the bear was in an ecotone or a mixed association).When 2 habitat hits were recor- ded,each was treated independently in our analyses.Thi s re- sulted in more habitat hits than observations.Brown bears had a total of 599 habitat hi ts and black bears 951. Preliminary habitat utilization analyses were conducted in two ways.The first analysis was based on the above-listed habitat categories recorded when the observation was made.No analysis of habitat-availability was possible on the basis of this analy- sis.The second habitat analysis was based on a physical over- laying of point-locations where bears were found on the 1:63,360 scale vegetation maps developed by the Agricultural Expt. Station.Vegetation types on these maps were interpreted from air photos within an approximate 5 mile strip on each side of the river ..Availability information for these vegetation-types on 10 - - -.. - - ~I -. this map are available for portions of the study area.Availa- bility for the actual impoundment area vegetation types was taken from 1:24,000 scale maps,elsewhere the 1:63,360 scale was used. Many bear locations fell outside of the area mapped at this scale. In 1981,each observation was categorized by ,the accuracy by which the location could be plotted on scale map:High=O-O.Ol mi 2 ,moderate=0.01-0.05 mi 2 , 0.20 mi 2 ),very low =>0.20 mi 2 • level of a 1:63,360 (low=0.05- - ,.... All data recorded during flights plus the above habitat data cal- culated subsequently were entered on computer data files by ADF&G Su-Hydro biometrics and data-processing staff.Point-locations were transferred to digetized point-locations and analyzed for horne range sizes,distances between points and movement rates from these data using geoprocessor software (ALARS)on the Data General computer system maintained by the Department of Natural Resources.Plotting routines associated with this system were utilized to produce most of the maps and illustrations utilized in.this report.Many of the data generated by the geoprocessor were entered for analysis onto the computer data file for obser- vation information.For a more thorough discussion of these ana- lytical procedures see the section on biometrics and data pro- cessing in the first annual report of ADF&G Su-Hydro big game studies (Miller and Anctil 1981). Bear use of areas in the proximity of the Susitna River was exa- mined by comparisons of use in 3 concentric zones:Within the actual impoundment area (159.3 km 2 for Watana and 28.9 km 2 for Devils Canyon),within a 1 mile zone surrounding each impoundment (incorporating about 486.6 km 2 for Watana and 193.7 km 2 for Devils Canyon,including the impoundment zone),and wi thin a 5 mile zone surrounding each impoundment (incorporating 1,795.6 km 2 for Watana and 958.2 km 2 for Devils Canyon,including the 1 mile 11 impoundment zone)(Fig.3).The 5 mile polygons for each im- poundment overlap by 151 km 2 •The calculated values for the areas of the Watana and Devils Canyon impoundments respectively were 99.4%and 124.6%of the values reported for these impound- ments in the subtask report for Plant Ecology prepared by the Agricultural Expt.Station,University of Alaska,(see Table 22 of this report).These Glifferences doubtless reflect errors resul ting from the different scales at which area calculations were performed.Proximity analyses were approached in two ways. First the area of each individual bear's home range that over- lapped each proximity polygon was calculated and expressed as a percentage of that individual's total annual home range.These percentage figures can exceed 100%when a portion of the home range overlaps the area of intersection of the polygons surround- ing both impoundments;the percentage value would be 200%if an individual's home range was entirely within this area of inter- section.Such individuals are in the zone of impact of each dam. The second type of proximity analysis examined the proportion of locations within each of these 3 proximity zones.The null hypo- thesis that bears were randomly using these three concentric zones would be rejected if the number of locations in each zone was not in the same proportion as the area of that zone.The areas of the 1 and 5 mile zones for this analysis were,respecti- vely,327 km2 and 1,234 km2 for the Watana impoundment and 165 kffi~and 690 km2 for the Devils Canyon impoundment.The area of overlap between the 5 mile polygons was divided at the Watana dam site so that half of the overlap area was subtracted from the 5 mile polygon for each impoundment.Similarily,point locations that fell within the zone of overlap or outside of any proximity polygon were divided so that each point was only counted once. The dividing line was a north-south line bisecting the overlapped 12 - - - area,points to the west of.this were counted in the Devils Canyon analysis and those to the east in the Watana analysis. This analysis understates bear use of the riparian habitat along the Susitna River as many points near the river that are outside of the 5 mile polygons (because they are upstream or downstream of the impoundment zone)are not recognized as being near the river.Some bias also entered into this analysis because of insufficient numbers of data points to conduct the analysis on a seasonal basis. Some biological significance to the 1 and 5 mile impact zone figures was obtained by comparisons with the "average home range .diameter"(AHRD)of each species."Home range diameter"was cal- culated by assuming that the calculated home range of each indi- vidual was circular in shape,the diameter of this circle was used in calculating AHRD.This is a minimal estimate of true home range diameter as a circle is the minimal way of encompas- sing any area.The AHRD for brown bears was 16.4 miles (range 8.5-45.0 miles)and for black bears it was 8.3 miles (1.9-19.5 miles).By these criteria the 1 and 5 mile proximity figures represent,respectively,6%and 30%of the AHRD for brown bears and 12%and 60%of the AHRD for black bears.These calculations clearly indicate that a 5 mile proximity polygon is a very con- se:rvative estimate of the actual impact zone,especially for brown bears.For statistical purposes,however,it was con- sidered necessary to use these minimal estimates of impact zones in making compari sons of bear use .of concentric impoundment proximi ty zones. Blood samples were analyzed for condition indices by Pathologists Central Laboratories,Seattle.Hair samples are stored for potential trace element analyses.Teeth were collected for aging according to procedures described by Stoneberg and Jonkel (1966) and Johnson and Lucier (1975).Feces collected during capture are stored for food habits studies (anticipated for Phase I I), and thin layer chromatographic techniques are being tested on 13 these specimens for potential utility in separating field- collected feces of brown bears from those of black bear (Appendix 6).This is an essential element of any food habits study based on fecal analyses in areas where both species are sympatric. Den locations of radio-collared bears were marked on the ground in winter 1980/81 and were visited 27 May-1 JURe at which time den measurements were taken and den characteristics recorded. Correspondin~marking and measurements have not yet been accom- '"; plished for 1981/82 den sites,correspondingly,the data pre- sented for these dens are preliminary (based on aerial locations, only)and subject to change once dens are marked and visited in 1982. VII.THE STUDY AREA Captured bears were located along the Susitna River and its trib- utaries between Devil Creek (T32N/R8W,Talkeetna Mts.Quad)and the Vee site or gaging station (T30N/R10E,Talkeetna Mts.Quad). The most distant bear captured south of the Susi tna River was G293 (upper Tsisi Creek),25 kIn south of the Susitna River.The most di stant bear captured north of the Susi tna River was G312 (T21S/R4W,Healy Quad),about 30 km north of the Susitna River. All black bears and about half of the brown bears were captured wi thin 5 km of the Susi tna River. Based on movements of radio-collared brown bears,the study area was expanded to include upper Chunilna Creek,the whole of Prairie Creek,the height of land separating upper Susitna drain- ages from Talkeetna River drainages,Kosina Creek,and drainages of the Susitna as far east as the Oshetna River,and upper Jay, Watana,Deadman and Tsusena Creeks.One subadult male brown bear (G342a)emigrated to the Petersville area outside of the illus- trated study area.The total area encompassed by movements of radio-collared brown bears (excluding G342a)inc'luded approxi- 14 - -- - mately 8,473 km 2 (Figure 1).Because of the difficulty of radio- .moni toring this large area,most monitoring efforts were con- centrated on a core area wi thin 15 km either side of the main Susi tna River,encompassing an area of only about 1,000 km 2 • Bears ranging outside of this core area were radio-located less frequently than bears with a greater portion of their home ranges wi thin the core area. Wi thin this study area,black bears were much less ubiquitous than brown bears.The main black bear study area was southeast and east of Devil Mountain to Tsusena Creek (T31-32N/R5-7W),an area which would be impacted by construction of the Devil Canyon dam.A secondary black bear study site,which would be impacted by the Watana dam,was centered around Deadman Creek or (T32N/ R'~-5W).The most upstream radio-collared black bear was upstream of the confluence of the Susitna and'Tyone Rivers in late summer 1981;this bear moved back downstream in the fall.Two black bears moved downstream to the vicinity of Gold Creek in late summer 1981,one of these returned to the primary study area ·to den.The black bear study area is indicated in Figure 2.The area incorporated by connecting the outermost points of recorded black bear observations (Fig.2)was 4,198 km 2 •Over half of thi s area,however,was not considered acceptable black bear habitat. VIII.RESULTS AND DISCUSSION -BROWN BEAR VIII.-A.SEX AND AGE COMPOSITION OF STUDY ANIMALS -BROWN BEAR The number of brown bears captured in connection with Su-Hydro s·tudies in 1980 and 1981 totaled 53.This total includes 11 re- captures of bears in order to replace radio-collars.Six bears, primarily males with large necks,shed their radio-collars (G277, G279, G214,G295,G309,and G347),and 4 bears were known to have 15 16 ....•~«»-«» E Q 10 Col l"- II E Q...-·~«»-III ~-•~ «» ~ III •Co-III oo ·.... E .ll:·l7• to) I"- "It' CD- - - - J ])]J i I J 1 1 j 1 ) '{ I l...,/ , f----r,I / ,'-~,--- :*"''*'.:.;(l,l~,.) il+:~,•..·..."f *.~1 :""'.,...if.'~',iI .,-~f_., ',''t,'k.-"~';t\*Y',,\,.i~:}:~,*"._",J,,}:'.__'.'.r..w.~~~~~".~£~~ II(-,*'~~~~~~_*llli:~:fL-:~._";+;~'~-~.."'-~:~~'".r ~'~~"." I )'~;+;,,,'""~~../~'="~'''-'',.•A i\<K'"/~~ -.-oj()i I j tz I' --~-/ / /' (II)() r-,'>/\.,.,->/\ ) / ) /,/ r C t ;" (!,/ I-' -..,J Figure 2.Blaak bear atudy area (4198 8q.km).722 blaak bear locatlona are lIIu8trated.(1 am =8000 meters) been shot by hunters (G297,G3ll,G284,G333).Four bears died during capture or recapture efforts (G278,G345,G308B,and G294).At present,15 brown bears have active radios,although one of these (G334)has been missing since September 1981 and may have been shot,one bear (G342a)emigrated out of·the primary study area,and another (G293)is a wide-ranging bear that is seldom found in the primary study area.A chronological list of bears captured and their current status is presented in Table 1. Five or more radio-locations were obtained for 5 male and 14 fe- male black bears.Numbers of radio-locations for each individ- ual,and current status,are given in Table 2.Primarily,be- cause of large males shedding radio-collars,the numbers of radio-locations for males (109)have been fewer than for females (422).Part of this disparity also resulted because 7 females were intensively monitored in Spring 1981 (114 locations)com- pared to only 1 male (14 locations)(Table 2).Sex and age structure of captured bears is given in Table 3. The age structure of bears captured for Susitna Hydro studies is essentially equivalent to that ·of intensive 1979 studies in the Upper Susi tna,to 10 years of GMU 13 harvest data,and to the subsample of radio-collared individuals (Table 4).As mentioned, however,the subsample of radio-collared individuals is biased in favor of females (Table 4). These data indicate that the sample of study animals is reason- ably representative in terms of age structure,but biased in terms of sex ratios. VI I I.-B.SPORT HARVESTS-BROWN BEAR ADF&G harvest data for brown bear in GMU 13 are given in Table 5. From 1973-1980,harvests averaged 64/year (44-84).During this period,the bag limit has been one bearlhunter every 4 years.In 18 ""'" - - ]i j J )-J 1 I )] Table 1.Brown bears captured in Susitna Dam Studies as of November 1981 Capture Tattoo Sex Age Wt.Date Frequency Flags Ear Tags Comments (277)F 10.5 225*4/10/80 orange 1065/1066 w/2 ylgs,not marked,collar shed 80/81 den (278)M 9.5 375*4/19/80 -- ----Capture mortality (279)M 9.5 400*4/20/80 orange 1100/1099 Collar shed by 6/12/80 280 M 5.5 300*4/20/80 orange 1097/1098 Recollar next spring (214)M 4.5 300*4/22/80 blue 1072/1071 Collar shed 9/9/80 281 F 3.5 250*4/22/80 orange 16175/15950 Not turgid 282 M 4.5 325*4/22/80 orange 1079/1080 283 F 12.5 280*4/22/80 orange 690/689 w2 @ 2.5:284 &285 (284)M 2.5 180*4/22/80 white ·1074/1073 w/283 see 5/5/81 recapture 285 M 2.5 180*4/22/80 .green 687/688 w/283 286 M 3.5 264 5/1/80 orange 1081/1082 292 F 3.5 174 5/2/80 green 1322/1321 Turgid 293 M 3.5 277 5/2/80 white 1116/1115 (294)M 10.5 607 5/2/80 white ----see 8/6/81 recapture (295)M 12.5 589 5/3/80 green 1303/1304 Collar shed by 5/4/80 299 F 13.5 285 5/4/80 green 1109/1110 w/2 ylgs,turgid (297)M 1.5 65 5/4/80 orange (1'301/1302)w/299,shot by hunter on 9/18/81 298 M 1.5 65 5/4/80 orange 1318/1317 w/299 306 F 3.5 163 5/4/80 white 1319/1320 Turgid 308A M 6.5 480 5/6/80 white 1126/1125 (308B)F 5.5 240 5/6/80 white 1096/1095 Turgid(?)-see 8/6/81 recapture (309)M 12.5 600 5/6/80 orange 1117/1118 Collar shed by 5/14/80 312 F 10.5 319 5/7/80 orange 1312/1311 w/311 (311)M 2.5 227 5/7/80 orange ----shot on 9/16/80 313 F 9.5 286 5/7/80 orange 1119/1120 w/314 @ 2.5 314 F 2.5 154 5/7/80 orange 1049/1050 w/313 315 F 2.5 90*5/7/80 green 1127/1128 alone (2841t)M 3.5 125 5/5/81 red CF 1074/1073 ·near 283 w/2c,shot by hunter on 5/18/81 331 F 6.5 172 5/5/81 white CF 1296/1295 w/332 &333 332 M 2.5 79 5/5/81 --1215/1216 w/331 &333 (333)M 2.5 67 5/5/81 --(1240/1239)w/331 &332,shot by hunter on 9/3/81 334 F 10.5 325 5/5/81 white CF 1292/1291 w/335,estrus 335 F 2.5 194 5/5/81 --1220/1219 28111 F 4.5 --5/6/81 white CF 1201/1202 estrus? 28311 F 13.5 261 5/6/81 white CF 1089/1090 w/338 &339 338 M 0.5 12 5/6/81 --1224/1223 w/283 &339,not drugged 339 F 0.5 13 5/6/81 --1222/1221 w/283 &338,not drugged 312ft F 11.5 280 5/6/81 white CF 1300/1299 w/2c @ 0.5-not captured 31311 F 10.5 284 5/6/81 white CF 1120/1119 w/336 336 F 0.5 --5/6/81 --1237/1238 w/313,not drugged (abandoned) (continued on next page) Table 1.Brown bears captured in Susitna Dam Studies as of November 1981 (cont'd) Capture Tattoo Sex Age Wt.Date Frequency Flags Ear Tags Comments 337 F 13.5 321 5/6/81 white CF 1294/1293 w/3c (2 captured subsequently not ear- tagged)reunited on 5/9/81 340 F 3.5 190 5/6/81 white CF 1225/1218 not estrus 280fJ M 6.5 394 5/7 /81 red CF 1097/1267 w/F 341 341 F 6.5 224 5/7 /81 white CF 1208/1207 w/M 280 29911 F 14.5 291 5/7 /81 white CF 1109/1110 w/2 @ 2.5 (297 &298-not recaptured), not estrus 342A M 2.5 220 5/7 /81 red CF 1228/1227 alone 344 F 5.5 --5/8/81 white CF 1204/1203 w/2 cubs subsequently (345)M 7.5 495 5/8/81 ------capture mortality (308B)It F 6.8 --8/6/81 ------recapture mortality 2991t F 14.8 --8/6/81 white CF 1109/1110 collar replaced 293#M 4.8 --8/6/81 red CF 1115/1116 collar replaced (294ft)M 11.8 --8/6/81 red CF -- -- recapture mortality (347)M 14.8 500*8/6/81 red 1234/1233 collar shed 9/81 N*Weight estimated,( )indicates shed collar or dead bear,#recapture, 0 collar or mark replaced subsequently ]J ~})I .J I .J )I .1 Table 2.Number of radio-locations of radio-collared brown bears for Su-Hydro studies ,. 1980 and 1981. ....Year of initial No.of radio-No.River Bear capture locations Crossings In (age)1980 1981*1980 1981 Comments MALES 342A 1981 (2)8 1 Active,moved downstream 293 19"80 (3)8 11 2 0 Active,wide-ranging ~~214 1980 (4)11 0 Collar shed,originally captured in 1978 280 .1980 (5)10 24 2 10 Active 308A 1980 (6)4 0 Missing** 279 1980 (9)2 0 Collar shed 294 1980 (10)14 8 1 0 Recapture mortality 295 1980 (ll)2 1 Collar shed 309 1980 (12)3 0 Collar shed 347 1981 (14)4 0 Collar shed All Males 54 55 6"IT FEMALES 335 1981 (2)34 0 Active 281 1980 (3)13 40 1 6 Active 340 1981 (3)39 6 Active 308B 1980 (5)15 13 5 7 Recapture mortality 344 (w/2c 1981)1981 (5)21 0 Active 331 (w/2c 1979)1981 (6)24 4 Active 341 1981 (6)28 9 Active I mWI 313 1980 (9)14 24 0 0 Active 277 (w/2 ylg 1980)1980 (10)6 0 Collar shed 312 (w/2c 1981)1980 (10)12 24 0 0 Active 334 1981 (10)31 0 Missing* 283 (w/2c 1981)1980 (12)12 19 0 0 Active 299 (w/2 ylg 1980)1980 (13)10 23 2 2 Active 337 (w/3c 1871)1981 (13)19 0 Active ~All Females 82 339 8 34 TOTAL BOTH SEXES 136 394 14 45-Observations of unmarked bears 24 32 TOTAL 160 426 14 45 *Includes radio-locations after 9/1/81 not dealt with in this report. **Possible unreported hunter kill,collar failure,or emigration 21 22 - - 1 ])1 J ]~I J j 1 ') Table 4.Average spring ages of Susitna area brown bear subpopulations.(Includes only bears of known sex and age that are 3.0 or older.spring age calculated as xx.5)• Males .Females Avg. Average Average Both Spring Age Spring Age Sexes % Subpopulations (Years)(Range)n (Years)(Range)n .(Years)Males GMU I3 fall harvests. 1970-1980 8.0 (3.5-23.5)208 7.7 (3.5-28.5)191 7.9 52 1979 Upper Susitna studies (Miller & Ballard 1980)7.4 (3.5-21.5)17 7.4 (3.5-16.5)15 7.4 53 1980-'81 Susitna Hydro studies*7.7 (3.5-14.5)14 7.9 (3.5-13.5)15 7.8 48 N Su~Hydro studieswradio-collared bears wi >5 locations*6.0 (3.5-10.5)4 8.6 (3.5-13.5)13 8.0 24 *Average of age at first capture Table 5.Summary of Brown bear harvest from Alaska's Game Management Unit 13, 1973-1980. Total Sport Average Age (N)%Total Harvest Taken in Falla %of Total Take Year Take Males Females Both Males Females Both By Non-Residents 1973 44 6.9(25)7.3(15)7.1(40)100 100 100 59 1974 72 6.3(39)7.3(28)6.7(67)100 100 100 47 1975 80 7.2(40)7.7(31) 7.4(71)100 100 100 46 1976 59 6.8(28)5.0(25) 5.9(53) 100 100 100 39 1977 38 6.1(28)7.1(6)6.3(34)100 100 100 32 1978 63 6.1(32)6.5(24)6.2(56)100 100 100 44 MIm: 1979 73 6.5(34)8.1(28)7.2(62)100 100 100 42 1980 84 5.0(39)5.8(31) 5.4(70)79 85 82 30 73-80 513 6.3(265) 6.8(188)6.5(453)96 97 97 42 Fall Only -6.3(255)6.9(183) 6.5(438) Spring Only -7.7(10)6.2(5)7.2(15) a Only fall seasons prior to 1980 24 ..... ..... ..... .... 1980/the first year with a spring season/males constituted 67% of the spring harvest/males const-i tuted 58%of the total fall harvests from 1973-1980.Even with spring seasons/most of the harvest -still occurs during the fall when bears are taken in- cidental to moose or caribou hunts.This pattern may change with the longer spring season planned for 1982/and with better spring hunting conditions.During the.period 1973-1980/42%of the brown bear harvest in GMU 13 has been taken by non-residents (Table 5). The mean age of brown bears taken during the period 1973-1980/ has been 6.5 years (6.3 for males and 6.8 for females)(Table 5). This relatively young age suggests that many GMU 13 hunters are not selecting for large trophy bears.Of 656 bears that have been harvested and aged in GMU 13 during the period 1970-1980/ 10%were yearlings/29%were 2 years-old or less/41%were 3 years-old or less/and 52%were 4 years-old or less (unpublished ADF&:G data).In 1980/one Unit 13 hunter even attempted to seal a cub bear.In recent years/sport hunters have applied pressure to extend brown bear seasons and bag limits in Unit 13.Thi s pressure has largely resulted from research showing that brown bears are significant predators of moose calves (Ballard et ale 1980/1981).Research suggesting a harvestable surplus of brown bears in the unit has also contributed to -the pressure (See Appendix 3). Recorded-brown bear harvests in the Susitna Hydro-project study area/1973-1980/have averaged 15/year (9-24/year)(Table 6). Hunting in the study area is.largely by aircraft/including some hunting by guided hunters/although many bears are taken from the Denali Highway.Indeed/the largest proportion of study-area brown bears are taken from subregions that include the Denali Highway (Table 6).Improved access to highway hunters resulting from hydro-project access routes will doubtless greatly increase brown bear hunting in the study area.This increased hunting effort combined with liberalized seasons and bag limits (encour- 25 26 - """ aged by some for Unit 13)could result in local overharvests of brown bear subpopulations in the study area.Most likely this overharvest would result in a reduction in bear density and a lowering of age structure rather than in an elimination of popu- lations. Brown bear kills in defense of life and property situations will also doubtless increase during proj ect construction and opera- tion.This is an inevitable result of increased human popula- ",,'.. tions in the study a'rea. """VI I I.-C.POPULATION BIOLOGY AND PRODUCTIVITY-BROWN BEARS - - .- Brown bears in the study area appear to be healthy and highly productive.Based on 9 litters with newborn cubs observed with marked adults since 1978,the mean litter size was 2.3 (range= 1-3).An unmarked bear with 4 cubs was also observed.Based on 16 litters of yearlings with marked females,the mean litter size was 1.6 (1-2),and based on 9 litters with 2 year-old offspring, it was 1.8 (1-2).Some of these litters represent the same in- dividuals observed in successive years.This mean litter size of newborn cubs is equivalent to highly productive bear populations on Kodiak Island and the Alaska Peninsula,and is higher than has been found in a relatively unproductive population in the Brooks Range (Table 7). Of 10 cubs in 5 litters produced in 1981,3 (in 3 litters)were lost during the summer of 1981 (Table 8).One of these losses (to G3l3)may.have been capture-related although Tait (1980)has suggested that abandonment of litters of single cubs may be an adaptive strategy for brown bears.Physical evidence (lactation) suggests that another bear (G308b)may have had a litter in 1981, but cubs were never observedi they may have been lost prior to the recapture of this bear in summer 1981.Two cubs in a litter of 3 were lost in 1979 studies (to G32l)as were 2 yearlings or 27 Table 7.Brown bear litter sizes reported in various North American studies. Source Area Average litter size (No.of litters observed) Age of litter 0.5 1.5 0.5-1.5 l\J ex> Pearson 1975 Martinka 1974 This study Reynolds 1976 Reynolds 1980* Mundy 1963 Klein 1958 Glenn et al.1976 Glenn 1976 &updated Hensel et al.1969 Craighead et al.1976 Southwestern Yukon Territory Glacier Natl.Park,Montana Nelchina Basin,Ala~ka Eastern Brooks Range,Alaska Western Brooks Range,Alaska Glacier National Park,B.C. Southeastern Alaska McNeil River,Alaska Black Lake,Alaska Peninsula Kodiak Island,Alaska Yellowstone National Park 1.7(11) 1.7(35) 2.3(9) 1.8(13) 2.0(33) 1.9(81) 2.2(25) 2.5(41) 2.1(19) 2.2(98) 2.2(68) 1.5(11) 1.8 (30) 1.6(16) 2.0(7) 1.9(21) 1.8(45) 1.9(35) 1.8(69) 2.1(51) 2.0(103) 1.6(22) 1.7(65) 1.7(10) 1.9 (20) 2.0(54) 1.9(126) 2.0(60) 2.1(110) 2.1(70) 2.1 (201) / /'. *My calculations from data presented in Table 3 of Reynolds (1980) I j i I }J J I ~~1 1 J J J ] Table 8.Brown bear offspring survivorship and weaning.Game Management Unit 13 studies.(Excludes bears transplanted in 1979.) Mother year Bear's 1 first ID (age)c~ptured 207 (11)1978 3 1978 cubs.April-Oct. STATUS 1979 1 y1g.survived.May- Sept.other 2 lost sur- vived by May (in den?) 1980 no data 1981 no data 220 (5) 221 (8) 204 (7) 1978 1978 1978 1 ylg ••May-Oct.1 @2y weaned in June.bred no data 2 y1gs .•May-Oct.2 @2 in May.radio failure no data 2 @2y in May.weaned in June and bred.no data no data no data no data no data 2 of 2 cubs survived May-Oct. 2 @2y weaned in May and bred 3 of 3 cubs survived May-Oct. Weaned 1 @2y in May and bred /" Weaned 2 @2y in May and bred 1 of 1 cubs lost in May. ~ossibly capture-related 1 of 2 cubs lost in June. other survived May-Oct. no data 2 of 2 ylgs.survived. May-Oct. Weaned 1 @2y in May.bred Weaned 1 @2y in May. breeding not observed no data Weaned 2 @2y in June.bred 1 of 2 cubs lost in August. other survived April-Oct. 2 of 2 y1gs.survived Apri1-no data August.collar shed in den 2 of 3 cubs lost in June. 1 survived April-Sept. )21 (12)1978 Bred I\J 299 (13)19801.0 312 (10)1980 313 (9)1980 283 (13)1980 277 (10)1980 331 (6)1981 334 (10)1981 337 (13)1981 344 (5)1981 1 Age ;age at first capture cubs in a litter of 3 (to G207)in the same year (Table 8).No other losses from yearling or 2 year-old litters were observed suggesting that offspring mortality is concentrated on cub classes. Causes of cub losses have not been determined although predation by male brown bears is considered most probable.A wolf was sighted near G312 at about the time her cub was lost in 1981. Hunters have sealed a total of 66 brown bears aged as yearlings during the period 1970-1980 (10%of the total harvest,un- published ADF&G sealing data)even though yearlings are protected by state law.Doubtless some of these harvested yearlings have been lone animals,unaccompanied by their mothers who have been shot or who weaned their offspring early;we captured one lone yearling (G315)in the early spring of 1980. Brown bear females in the study area typically accompany their offspring through their yearling year and wean them as 2 year- olds in Mayor June of the following year (Table 8).As yet,no cases of a female entering a den with a litter of 2 year-old offspring have been observed in Unit 13 studies (Table 8).Many of the females breed again soon after weaning (as evidenced by association with another bear);in all 3 cases where the subsequent year's data are available,this breeding was successful as evidenced by newborn cubs (Table 8).For these 3 bears,the reproductive interval was 3 years,doubtless addi tional data will reveal a mean reproductive interval for adu1 t females between 3 and 4 years.An estimate of 3.3 years was used in productivi ty calculations ,(Table 9.) Typically,female brown bears in the study area first breed at 3 or 4 years of age and produce their first litter when they are 4 or 5 years-old.Observed litters were produced when the mother was 4 years-old in 4 cases,when she was 5 years-old in 2 cases and when she was 6 years-old in 1 case (possible litter by G308b, aged 6,not included)(Table 10).Five barren females at age 4, 30 - ..... - J J 1 ]1 J J J i )i 1 Table 9.Reproductive rates of grizzly bear populations (First four data sets,and analytical procedure, are slightly modified from that presented by Reynolds 1980). Mean Age at 1st Potential Production to Reproduction Potential x Reproductive Maximum Age of Life 'Repro-Litter Production Rate (No.cubs/ Area Breeding ductive Interval Size of Cubs*adult female/year) Yellowstone Park (Craighead et al.1976) Alaska Peninsula (Glenn et al.1976)** Eastern Brooks Range (Reynolds 1975)** Western Brooks Range (Reynolds 1980) Nelchina Basin (this study) Nelchina Basin (this study) 6.3 -24.8 18.5 years x 2.24 =12.2 0.66 3.40 6.3 -24.8 l~ears x 2.50 =12.3 0.66 3.77 10.1 -24.8 14.7 years x 1.78 =6.2 0.42 4.24, 8.4 -24.8 16.4 years x 2.03 =8.3 0.50 4.03 5.2 -24.8 19.6 years x 2.3 =13.7 0.70 ~ 5.2 -14.4***9.2 years x 2.3 =6.4 0.70 3.3 *This potential may be close to actual in lightly hunted populations in Yellowstone and the Brooks Range,it probably over estimates productivity of heavily hunted population (Ak.Peninsula). **Reynold's (1980)analysis of data presented by others. ***Maximum age based on mean age of 30 females (~12 years)in the sport harvest 1970-1980. / /, Table 10.Reproductive intervals of female brown bears captured for Su-Hydro studies and previous Nelchina Basin studies. Bear ID Spring age of female when first observed Season first litter was produced ~tured YEAR IN WHICH OFFSPRING WERE PRODUCED AS CUBS 1 1976 1977 1978 1979 1980 1981 1982 2Mc 2Xb 1Mc 2Mb 1M.1Fa 1F c 2X a 2M c 1F a 1F c 3X a 2X a a1M.IF.IX SU-HYDRO STUDIES (277)9.5 spring.1980 283 10.5 spring.1980 299 12.5 spring.1980 312 2 8.5 spring.1980 313 7.5 spring.1980 331 4.5 spring.1980 334 8.5 spring.1980 337 ,13.5 spring.1981 344 5.5 spring.1981 NELCHINA BASIN STUDIES (Spraker.e~al.1981) w l\J 207 11.5 spring.1978 213 3 9.5 spring.1978 1Xb 204 6.5 spring.1978 IF.1Xc 1~220 4.5 spring.1978 221 7.5 spring,1978 2X 231 13.5 spring.1979 206 14.5 spring.1979 2Xb2344.5 spring.1979 240 4.5 spring.1979 244 5.5 spring.1979 251 9.5 spring.1979 254 8.5 spring.1979 261 6.5 spring.1979 269 15.5 spring,1979 274 10.5 spring.1979 1 Litter size followed by:M=male.F=female.X-unknown sex 2 Second offspring lost,capture-related 3 First offspring lost.capture-related a Litter first observed as cubsbLitterfirstobservedasyearlingscLitterfirstobservedas2.0+years old ( )Bear shot by hunter.collar shed.or otherwise inactive ~~b;~ ;~ 1Mb 1Fb 2Ma 3X a 3Xa / /, / cl ~~.J J _cJ ~_~J )J ,~_..J .1 ..J J 4 barren females at age 5 (one of these also included at age 4), and 1 barren female at age 6 (G308b not included)have been cap- tured in Unit 13 studies since 1978 .Although these data sets are not directly comparable,they suggest that about 44%of the 4 year-old females produce litters,33%of the remaining barren 5 years-old,and 50%of the remaining barren 6 years-olds.Ob- viously some of the 5 and 6 years-old barren females could have previously produced,but lost,litters. All of the barren females aged at 4-6 years when captured (n=lO) were in estrus;estrus did not lead to parturition for at least one bear (G209)who was barren again the subsequent year (1979) at age 5.At age 4,this bear was observed numerous times with another bear indicating probable breeding acti vi ty.Interest- ingly,3 of the 6 barren females aged at 3 years-old that have been captured were in estrus.If this estrus led to successful breeding (not determined)it would yield the 50%parturition rate suggested above for 4 year-old females.In 1981,a large 2 year- old female (G335,not noticeably in estrus)was captured with her mother (G334),was subsequently weaned and was observed fre- quently with a larger,presumably adult male,bear through the summer of 1981 (no copulation behavior was observed).If G335 produces cubs in 1982,this would reveal at least one case of successful breeding at 2 years-of-age,1 year younger than in- dicated above.However,the companion of G335 could have been an uncaptured sibling. All seven or eight year-old females that have been caught were ei ther with litters or showed evidence of having had a litter previously.Based on these data,it appears that for every 100 females (~4 years),about 44 will produce their first li tter at age 4,20 at age 5,19 at age 6 and 18 at age 7 (these estimates are slightly more conservative (less productive)than indicated by available data).Based on these calculations,the mean age at which these 100 hypothetical females produce their first litter is5.2 years. 33 The length of time female brown bears in the study remain pro- ductive is more difficult to determine.The oldest female captured was G269;this bear had 2 yearlings with her when captured at age 16 in 1979.Two 14.year-old (G206 and G299)and three 13 year-old females (G283,G206,G23l)have been captured; all had litters.The oldest aged female in the sport harvest since 1970 was aged at 28 years-old,only 10%of the female sport harvest has been aged older than 12.0 years during this period. The average age of females older than 12.0 taken in the sport harvest was 14.4,compared to 13.6 years for the 7 females older than 12.0 years that have been captured during Unit 13 research efforts since 1978.The best figure to use in calculating the period females are reproductively active would be the mean ex- pectation of life of females older than 4.0,however,data are currently inadequate to calculate this.Therefore,the pro- ductive life span of females was bracketed using the mean from other studies (24.8 years)and the average age of females older than 12.0 years from the sport harvest data (14.4 years). These parameters were used to compare the productivity of the study area population with those elsewhere utilizing the pro- cedures,and data from other populations that were presented by Reynolds (1980)(Table 9).The only change made from Reynolds' presentation of this data was that "maximum age of breeding"was standardized at the mean of 24.8 years instead of fluctuating from 22.5 to 26.5 years in different areas;insufficient data are available to reasonably identify differences in maximum breeding age between different areas,so it was considered more realistic to hold this parameter constant. The study area productivity data are clearly preliminary as in- sufficient data are available for this popul'ation.Also,these productivi ty data should not be used in estimating allowable harvest,as they compare potential productivity.Actual pro- ductivity is dependent on the age structure of the female segment of the population (heavily harvested populations would have a 34 .... ~ I - '""" - relatively lower mean female reproductive life)and recruitment -(a function of offspring losses prior to weaning).Longer term data on other estimated parameters are also needed prior to cal- culation of productivity estimates that have reasonable levels of confidence.With these limitations clearly in mind,however,it is evident that the available data strongly indicate that the study area population has a high potential pr?ductivity relative to populations in Yellowstone and elsewhere in Alaska (Table 9). .- This largely results from the lower age of first litter produc- tion in the study area. Preliminary data suggesting that the brown bear populations in ~the study area may produce pulses of cubs every 3 years are shown in Table 11.With a 3 year reproductive interval and many fe- males becoming reproductively mature at 3 years of age,an especialy large crop of cubs in one year might result in pulses of cub production every 3 years.This model is hypothetical at this point. VI I I.-D.POPULATION DENSITY -BROWN BEAR Determination of the number of bears in the Susitna study area was defined as a major objective of this study.Bear population estimates are exceptionally difficult and expensive to obtain and an accurate estimate was not achieved with the funds available for Phase I bear studies.An imprecise estimate may be ulti- mately obtainable from radio-tracking determinations of home range size·coupled with an estimate of the proportion of the pop- ulation which is radio-collared.The precision of such estimates increases as the proportion of the population which is radio- collared increases.Because of the apparent abundance of brown bears in the Susi tna study area and because of the large home range sizes of Nelchina brown bears (average=570 km2 ,range= 192-1,380 km 2 ,Ballard et al.in press),it will be expensive to obtain a preci se estimate. 35 Table 11.Annual production of brown bear litters in Game Management Unit 13. (Represents data collected during studies from 1978 through 1981 on litters observed with radio-collared and newly-captured bears. extrapolated back to the year litter was produced). YEAR LITTER WAS PRODUCED 1976 1971 1978 1979 1980 1981 TOTALS No.litters observed 1 3 11 6 1 5 27 %of total 4%11%41%22%4%19%101% No.offspring observed 2 5 19 13 2 10 51 %of total 4%10%37%25%4%20%100% Above data based on observations of litters of:cubs yearlings 2 y-olds No.of litters (%)9 (33%)13 (48%)5 (19%) No.of offspring (%)21 (41%)23 (45%)7 (14%) 36 ,~ Jl'llilI1!l. - ..... ""'l 'I - .... An imprecise estimate of brown bear density was obtained from intensive trapping and mark-recapture techniques conducted in the Sus'itna River headwaters in 1979 (Miller and Ballard 1980)(see Appendix 3).This estimate is compared with other North American estimates in Table 12. Based on a density estimate of 1 bear/4l krn 2 ,the Susitna study area of 8,473 km 2 would have a population of 206 brown bears.It is our subjective evaluation that brown bear density in the Susitna study area is more likely to be higher than that esti- mated in our earlier study,rather than lower.However,using this estimate,it can be seen that only about a fifth of the bears inhabitating the study area have been captured and that only 7 percent are currently radio-collared:An accurate density estimate may be obtainable only when many more of the brown bears utilizing the study area have been captured and marked. VIII.E.HOME RANGE AND MOVEMENTS -BROWN BEARS 1 .'Home Ranges-Brown Bear Horne range sizes for brown bears radio-collared for Su-Hydro studies are given in Table 13,these data are compared with re- sults of nearby 1978 studies (Ballard,et al.in press)in Tables 14 and 15.Significant differences between 1978,1980,and 1981 data sets were obtained only for females which had smaller horne ranges in 1980 than in either 1978 (P<O.aS)or 1981 (P<O .10) (Table 15).Plots of the horne range of each individual in this study with 5 or more relocations are presented in Appendix 1. Brown bear horne ranges appeared larger in 1981 than in 1980, al though the differences were not significant because of large variances (Table 15).This difference was present even though """the 1981 data are analyzed only through 1 September.One male - 37 Table 12.Reported brown bear densities in North America. Location Source Kodiak Island.AK Troyer and Hensel 1964 Alaska Peninsula.AK Unpublished data (Glenn pers.comm.)** Glacier Nat.Park.Montana .Martinka 1974* Glacier Nat.Park.B.C.Mundy and Flook 1973* SW Yukon Territory Pearson 1975* Upper Susitna R.•AK Miller and Ballard 1980 Western Brooks Range (NPR-A).AK Reynolds 1980 Eastern Brooks Range,AK Reynolds 1976 intensively studies area of the central Alaska Peninsula. ***Mean is for the whole of the Nat.Pet.Reserve,AK.the range represents values for different habitat types in this reserve where the highest density occurred in an intensively studied experimental area. J J .1 I J I J )·1 J J ) l j 1 1 J J )-1 )l'))1 )J •1 Table 13.Horne range sizes for Su-Hydro study area brown bears.(Includes individuals with 5 or more relocations). 1980 1981*Ho,e Range Bear 10 Observation Period Home R2nge Observation Period Horne R2nge (km )1980 (age @ capture)(No.of locations)(krn )(No.of locations)(km )&1981 Comments MALES 342a (2)------May-September,(5)1774**---dispersed no den* 293 (3)May-October (8)1409 May-September,(9)2655 4135 wide-ranging no den no den* 214 (4)April-September (11)975 ---------shed collar 280 (5)April-October (10)499 April-July,(21)427 743 no den* 294 (10)May-October (14)495 May-August (8)100 611 recapture mort.x (all males)=(10.8)845 (10.8)1239 1830 S.D.=--439 --1190 range =(8-14)495-1409 (5-21)100-2655 611-4135 FEMALES 335 (2)------May-September,(28)179 --weaned in 1981 no den* w 281 (3)April-October (13)189 April-September(3~)330 330 single\0 no den* 340 (3)------May-September,(33)613 --single no den* 308b (5)May-October (15)142 May-August (13)110 191 recapture mort. 344 (5)------May-September.(15)246(w/2c) no den* 331 (6)------May-September.(18)1136 --weaned 2@2 in '81 no den* 341 (6)------May-September.(23)536 --breeding no den* 313 (9)May-October (14)82 May-September,(18)196 218 lost 1c in May '81 no den* 277 (10)Apiil-October (6)147(w/2@1)-------shed collar in den 312 (10)May-October (12)140 May-September,(19)163(w/2c)280 no den* 334 (10)------~ffiy-September,(29)111**weaned 1@2 in '81 no den* (continued) Table 13.(cont'd) Bear 10 (age @ capture) 283 (12) 299(13) 1980 Observation Period (No.of locations) April-October (12) May-October (10) Home ~ange (km ) 233 188(w/2@1) 1981* Observation Period (No.of locations) Home ~ange (km ) H02e Range (km )both 1980 &1981 Comments ~o *1981 relocation data have been compiled only through September 1.subsequent relocations including 1981 dens will change these results. **Not included in statistical comparisons (Table 15) i •J ~J J J J m I I I I !..1 ..I j ))I "~)1 })1 j J ]1 J ]J Table 14.Comparisons of mean home range size of brown bears radio-collared in 1978 (Ballard,et.al.in press),1980, and 1981 studies in Unit 13.Includes all bears 3 years of age or older. MALES FEMALES BOTH SEXES 1978 1980 1981*1978 1980 1981*1978 1980 1981* Mean Home range 2 769 845 1061size(km )408 160 343 572 409 487 S.D.396 439 1390 222 48 302 356 422 660 Range 282-1381 495-1409 100-2655 193-734 82-233 50-1136 193-1381 82-1409 50-2655 n 10 4 3 12 7 12 22 II 15 Mean age of sample 6.9 5.5 7.0 8.8 8.9 8.4 7.9 7.6 8.1 Range=3-11 3-10 4-11 4-13 3-13 3-14 3-13 3-13 3-14 Mean No. relocations/ bear=16.2 10.8 12.7 24.9 11.7 20.8 21.0 11.4 19.1 Range=8-29 8-14 8-21 12-33 6-15 13-35 8-33 6-15 8-35 %Males 45 36·20 %of Females 8 0 33 w/newborn cubs *Includes data through September I,1981 only,actual 1981 home range sizes will be larger when all 1981 points are included in analysis. 42 - - ..... (G293)and 5 females (G28l,G3l3,G3l2,G283,and G299)were re- located 5 or more times in both 1980 and 1981 during roughly equivalent portions of the year (Table 13).The 1981 home ranges were larger (P>O.lO)for 5 of these bears in 1981 (x=740 km 2 , 8.D.=1074)than in 1980 (x=402 km 2 ,8.D.=565);the mean percent- age increase in home range for these 5 bears was 81%(range = 16%-139%)•The bear with the smallest increase in home range size (G3l2,+16%)had newborn cubs in 1981 as did the bear (G283) that showed a decrease in home range size (-79%)between 1980 and 1981. In comparison with studies in other portions of Alaska,Canada and Montana,brown bears in the Su-Hydro study area have rela- tively large home ranges (Table 16).Only in northwestern Alaska,a relatively unpro~uctive population,have larger home ranges been reported (Table 16).All of these populations are also more densely populated than the study population,except for the northwestern Alaskan population (Table 12).Although,a clear relationship has not been established,we suspect that home range size and bear density are inversely related and that both are a function of the distribution and abundance of food resour- ces.The relatively large home ranges and low densities of study-area brown bears may reflect,therefore,relatively low primary productivity of food items important to brown bear in the study area;these data may also reflect a patchy and wide-spaced distribution of important food items in addition to or instead of low primary productivity.Supporting this relationship are observations indicating that in areas of Alaska where salmon re- present a primary source of food,home ranges tend to be smaller and densities higher such as on Kodiak Island and the Alaska Pen- insula (Tables 16 and 12).Confounding this apparent relation- ship,however,is the apparent high productivity of study-area brown bear populations (see Section VIII-C this report).If food were limiting this population,a relatively lower reproductive potential,such as has been found in northwestern Alaska,would be expected~ 43 Table 16.Comparison of reported home range sizes of brown/grizzly bears in North America (adapted from Reynolds 1980). Sample He an ~ Area Sex size home range (km2 )Source Kodiak Island,Ak.1'1 7 24 Burns et.aL 1'977 F 23 12 ~ Yellowstone National H 6 161 Craighead 1976 Park F 14 73 Southwestern Yukon 1'1 5 287 Pearson 1975 F 8 86 -Northern Yukon 1'1 9 414 Pearson 1976 F 12 73 Western Montana M 3 513 Rockwell et aL F 1 104 1978 Nelchina Basin M 14 790 This study (1978 &~ F 19 316 1980 results only) Northwestern Alaska M 8 1350 Reynolds 1980 F 18 344 ..... ...." 44 ..... ..... During the period of den selection many brown bears typically move to higher elevations,outside of their normal home ranges during non-denning seasons.This is reflected in comparisons of home range sizes which include and exclude locations at or in dens for 8 brown bears in 1980.The mean increase in home range size for these bears when den locations were included was 30% (0-151%)•Doubtless these data will change once data for the 1981 den sites are compiled. Mean elevation by month of observation of radio-collared brown bears is given in Table 17.Females with newborn cubs have a significantly higher mean elevation than other bears (T=9.94 , P<O.OOl).Typically bears were at the lowest mean elevation in June-August (Table 17). The area of overlap of brown bear home ranges with the impound- ment area and with the area enclosed by polygons constructed 1 mile and 5 miles from the proposed impoundment shorelines were determined (Figure 3).The mean overlap with the impoundment area was 5%(0-25%),with the 1 mile polygon it was 15%(0-48%), and with the 5 mile polygon it was 52%(0-100%)(Table 18).As discussed in the Methods section,these data underrepresent the amount of use of the area in,and in the vicinity of,the pro- posed impoundments because the home range figure used in cal- culating percent overlap was the total annual home range,sea- sonal use by many brown bears was more intensive (see following section on seasonal movements).Regardless,these data clearly demonstrate that even the minimal impoundment-impact area repre- sented by a 5 mile polygon would influence a mean of over 50%of the home range area occupied by the study population.As discussed in the Methods section,the 5 mile polygon represented only 30%of the "Average Home Range Diameter"calculated for brown bears,for this reason it is a minimal approximation of the impact-area of the proposed impoundments.A 5 mile polygon was used not because it represented a biologically meaningful 45 Table 17.Mean elevation by month of radio-collared brown and black bears. Males and Females with newborn cubs Females wlo newborn cubs Males Females wlo newborns (ft)S.D.N (ft)S.D.N (ft)S.D.N (ft)S.D.N Month BROWN BEARS (data through 1 Sept.1981 only) May 4357 423 25 2877 840 93 2436 855 24 2787 858 117 June 3473 447 10 2773 557 94 2577 773 22 2736 605 116 July ·3423 548 9 2757 470 40 2301 498 17 2621 518 57 August 3016 472 11 2786 494 39 2259 441 17 2626 534 56 September 3219 329 4 3090 570 14 2546 718 7 2908 .659 21 Oct.-April 4842 52 3 3786 1103 19 2950 832 13 3446 1071 32 whole year 3791 730 62 2884 724 299 2488 727 100 2785 744 399 -- ,j:.. BLACK BEARS (all 1980 and 1981 points) 0'1 May 1963 308 8 2048 309 42 2233 409 84 2166 386 132 June 2177 302 12 2221 271 44 2341 442 74 2296 390 118 July 2153 196 8 2338 326 31 2394 265 44 2371 291 75 August 2076 286 17 2165 307 48 2234 459 67 2202 402 116 September 2217 347 15 2284 332 45 2088 624 46 2185 508 91 Oct.-April 2194 355 4 2022 382 14 1953 340 12 1990 351 27 whole year 2131 302 64 2189 327 231 2248 456 327 2223 408 559 J !J J J J I J )I I I J J 1 1 J J J j ]]i J ]1 J J j Table 18.Areas of intersection of brown bear annual home ranges with each impoundment and with 1 and 5 mile impoundment proximity polygons.(Home range data from Table 13). Area of Intersection Area o{--Intersection Area of Intersection with Impoundment +1 mile +5 miles Bear ID Home Watana Devils Total Watalla Devils Total Watana Devils Total (age)Range (km 2 )(km 2 )Canyon %over-(km2 )Canyon %over-(km 2 )Canyon %over- (km 2 )lapped (km 2 )lapped (km 2 )lapped MALES 342a(2)1774 0 16.3 0.9 0 120.9 6.8 63.4 629.4 39.1 293 (3)4135 155.4 0.8 3.8 451.2 10.5 11.2 1349.1 172.8 36.8 214 (4)975 49.5 0 5.1 256.4 0 26.3 523.7 0 53.7 280 (5)743 83.6 0 11.3 197.7 0 26.6 486.0 0 65.4 294(10)611 0 13.7 2.2 0 77.3 12.7 29.9 320.7 57.4 FEMALES 335 (2)179 0 0 0 0 0 0 15.1 0 8.4 281 (3)(w/cubs in '81)330 82.7 0 25.1 158.4 0 48.0 296.8 5.7 91.7 340 (3)613 61.0 0 10.0 168.4 0 27 .5 488.6 0 79.7 308b(5)191 0 14.4 7.5 0 82.3 43.1 0 189.1 99.0 344 (5)246 0 0 0 3.5 0 1.4 174.9 0 71.1 331 (6)1136 50.4 0 4.4 112.5 0.2 9.9 388.3 80.1 34.2 341 (6)536 43.1 0 8.0 126.4 0 23.6 309.5 0 57.7 313 (9)218 0 0 0 0 0 0 84.6 34.9 54.8 277 (10)147 0 0 0 0 0 0 0 0 0 312(10)(w/cubs in '81)280 1.4 0 0.5 11.0 0 3.9 93.9 0 33.5 (Continued) Table 18.(Cont'd) Area of Intersection Area of Intersection Area of Intersection with Impoundment +1 mile +5 miles Bear ID Home \.Jatana Devils Total Watana Devils Total Watana Devils Total (age)Range(km 2 )(km 2 )Canyon %over-(km 2 )Canyon %over-(km 2 )Canyon %over- (km 2 )lapped (km 2 )lapped (km 2 )lapped 334(10)(w/cubs in '81 111 0 0 0 0.3 0 0.3 53.7 0 48,lf 283 (12)323 0 12.9 4.0 0 76.3 23.6 59:1 263.7 99.9 299(13)585 54.7 0 9.4 108.1 0 18.5 343.4 3.3 58.7 337(13)(w/cubs in '81)270 0 0 0 0 0 0 6.5 0 2.4 mean =4.9 14.9 52.2 ~*Percentage figures do not accuratley portray impoundment-related habitat losses as home range size usedcoreflectstotalannualhomerange,percentage figures based on seasonal home ranges would be higher especially during spring and early summer. I !J J I ~J I .J I I J J CD '1:J C lG Q) CD C 0 at >- 0a. >.--E K 0..a.-0 c CD 0 -=C lG Q)..E-'1:JCDC~~-0a. E. t")c Q)0..>-~CatlG ~0' =E..c o tI.. lG-lG ~- '1:J Q) CDoa.o..a. Eo..- =Q)..o ~ CD Q) ~- = CD Q) -o Q) c > Q) C '1:J C lG lGc lG-lG 3: = ----§cc ~ ____§E cc Q) :::>- ----5c F ~ ----§cc '"... ----§c C N... ----§cc <:>... ( I i - estimate of the impoundment-impact areal but rather because of statistical needs associated with proximity analyses (see section VIII-E-5 of this report). 2.Brown Bear Movements to Fi shing or Hunting Sites Prairie Creek which flows from Stephan Lake to the Talkeetna River is well known as an area where brown bears concentrate in July and August to feed on salmon,especially king salmon. Alaska Department of Fish and Game sport fisheries biologists characterize Prairie Creek as having on~of the highest concen- trations of spawning king salmon in the Cook Inlet region (Larry Engle I pers.cornrn.). Radio-collared brown bears moved to Prairie Creek to fish for salmon in both 1980 and 1981.UnfortunatelYI bad flying condi- tions in 1981 prevented ~omplete docume~tation of how many bears made this movement.At a minimum,4 bears (G308b,G293,G294) moved to Prairie Creek in 1980 (of 11 with active radio-collars) and 2 (G293 1 G294)in 1981 (of 18 with active radio-collars). The longest distance moved by a bear to Prairie Creek was 58 krn (G293 in 1981),after leaving Prairie Creek this bear was located 94 krn from this fishing site.For 4 of these 6 known movements to Prairie Creek l a crossing of the proposed impoundment areas was documented (no crossings were documented for G294 and G293 in 1981).The annual horne ranges of the 6 bears known to have moved to Prairie Creek is presented in Figure 4.Connecting the outer- most points of these observations enclosed an area of 5,773 krn 2 , the documented minimum area from which bears are attracted to Prairie Creek. The Prairie Creek salmon resource is doubtless more widely uti- lized by study area brown bears than these data indicate;poor weather which results in missed flights and relatively infrequent monitoring would yield an underdocurnentation of actual use. Local residents have reported seeing 20 bears at one time on 50 - - - 1JII!IlIlIl:!, - ,- , .- / I -:h •-..::I •.,-c .,_ e c 0otoe01 ca ...••..eo0-.. ~-•-. 0 e-..: ..:. a'•••..(l) ()... •...-10..-ca 0.. Do • 0 •..-••'a-C ••-e c••E:.- 0 ::I 0e0 'a 'a •ca-c E•E 0.. :t -0 •0 .. 'a • ~•-,Q ••- •0..ca·..· = .Q • C ..:••o •.. .. ,Q () G •-':o •·.. •DoatC•·....CD·~Eo 'a~C• • 0 ::I CD C CD C ..<.-••:t ...at •:t..< :t at 'a -C~. Prairie Creek.On 10 August 1980,past the king salmon peak,we saw 13 brown bears at one time on Prairie Creek.We estimated that 30-40 individual brown bears fished in this area in the sum- mer of 1980. The importance of the Prairie Creek salmon run to study area brown bears will be difficult to evaluate.Other studies (Miller and Ballard,Appendix 3),indicate that moderately dense brown bear populations exist in the Nelchina Basin without access to salmon.However,it is possible that the availability of this interior run of salmon might provide nutritional benefits that result in local bear populations that are more dense or less nutri tionally stressed than adj acent populations without access to a salmon run.Prairie Creek salmon may also be an important buffer during years when other sources of forage are limited. Preliminary conversations with sport fish biologists (ADF&G) suggest that Prairie Creek salmon runs are unlikely to be nega- tively affected by the proposed impoundments,however specific salmon studies will not be completed for 5 years.Assuming the proposed dams have no impact on the strength of the salmon run in Prairie Creek,the main impact the proposed construction might have on bear movements would be a physical blocking of seasonal movements to or from Prairie Creek. All of the radio-collared bears seen at Prairie Creek had por- tions of their home ranges north of the Susitna River and there- fore had to .cross the river enroute to or from Prairie Creek. The maximum number of times an individual brown bear was known to have crossed the Susitna River was 10 (Table 2).It is unknown whether the bodies of water in the proposed impoundments would, in themselves,represent a significant barrier to bear movements, however,this possibility cannot be discounted.In addition,the strangeness of mud banks created by fluctuating water levels (if such occurs in midsummer)might represent an equal or greater barrier,perceived or real,to bear movements across the impound- ment.Heavily traveled access roads to the impoundment might 52 - - - .- - - - - also inhibitor block bear movements across these roads;any access road bui 1t from the Parks Highway to the Watana damsi te would have to be crossed by some bears moving between the Susitna River and Prairie Creek.Observations of homing brown bears being deflected,both permanently and temporarily,by large strange river beds and highways have been reported in Alaska (Miller and Ballard in press). Seasonal movements of brown bears to areas where moose or caribou congregate,as on calving grounds,are difficult to document. For moose calving areas,which are poorly defined in any case, bear movements to lowland areas to prey on calves in the spring cannot readily be distinguished from movements to these same areas which may be'motivated by the presence of relatively more abundant early spring forage.For 4 bears,however,apparent directional movements to or from caribou.calving grounds were observed.A 3 year-old male (G293,Fig.17)and a 6 year-old female (G33l,Fig.23)were sighted in early spring 1981 in close association with the Nelchina caribou herd on their 1981 calving grounds on the upper Oshetna River.G33l made an obvious directional movement to this area from upper Clark Creek, previous locations in spring 1981 were not obtained for G293.In similar fashion,G280 (a 4 year-old male,Fig.14)and G299 (a 13 year-old female with 2 yearlings,Fig.19)moved to upper Kosina Creek in spring 1980. ADF&G biologists conducting caribou surveys (S.Eide,·R.·Tobey, and K.Pitcher,pers.comm.)regularly report seeing many brown bears associated with the Nelchina herd.For example,in early July 1980,these biologists made incidental observations of 22 brown bears in approximately 260 mi 2 of survey area during cari- bou surveys on the upper Oshetna River.This represents a mini- mum bear density of 1 bear/12 square miles during this seasonal concentration of bears.Since only a fraction (perhaps a third) of the bears present were likely to have been seen by biologists concentrating on caribou,the actual local bear density in this 53 area may have been much higher.In illustration of this obser- vability bias,in 1981 these biologists conducting the same sur- vey in about the same area saw no bears even though some radio- collared individuals were present as discussed above. 3.Dispersal - Dispersal both to and from the study area by subadult brown bear is probably common.Unlike black bears,brown bear populations in the study area are in the middle of a large area of natural brown bear habitat and their dispersal behaviour here is probably typical of the species. Male G214 was originally tagged as a 2 year-old in 1978 on the Susitna River and Valdez Creek (north of the Denali Highway).In spring 1980,this bear was captured,and radio-collared,near Clarence Creek (between Vee Canyon and Jay Creek)on the Susitna Ri ver.Ai though thi s bear ranged north a considerable di stance prior to shedding his radio-collar (Fig.12),it appeared that he dispersed to the study area as a subadult from his 1978 capture site. Male G342a (2 years-old,Fig.29)was captured near Deadman Creek in the middle of the study area in spring 1981.He was located on Portage Creek shortly thereafter and apparently then moved about 55 miles down the Susitna River to Moose Creek (Talkeetna Quadrangle B1)by mid June.In the fall,this bear moved back upstream to Indian Creek (Talkeetna Mountains Quadrangle D6)and then downstream and denned between Sherman and Curry (Talkeetna Mountains Quadrang'le C6).This is apparently a long dispersal downstream followed by a partial return (during the salmon run in the fall).This bear may now be resident between Sherman and Curry. 54 -. _. ..- 4.Seasonal Use of Impoundment Impact Areas -Brown Bears In our first annual report,we suggested that brown bear use of the impoundment area was most prevalent and important in early spring,soon after bears emerge from their winter dens.We hypo- thesized that these movements were motivated by relatively earlier melt-off of snow,especially on south-facing slopes, which made these the first areas where overwintering berries could be found and also the first areas where new growth was available..Winter-killed or weakened ungulates might also be prevalent in these areas of ungulate winter range. Overwintered berries were common in scats of bears captured in spring 1980 especially for bears captured along the river.The lack of protective snow cover in the winter of 1980/81 apparently prevented successful overwintering of berries and bears appeared to be eating more ground squirrels in spring 1981.Regardless, the available data strongly support the theory that early spring is the period when many brown bears are most intensively utili- zin<;J the impoundment-impact area (conservatively defined,for this analysis,as wi thin 1 mile of the high water mark of the proposed impoundments). Of 12 bears radio-collared in spring 1980,6 were located in the impoundment-impact area at least once (Table 19).The mean ele- vation of these observations was 1984 feet for the Watana area and 1971 feet for the Devils Canyon area (Table 19),below pro- posed high water lines for the former but not for Devils Canyon. Thirty percent of all 1980 spring observations of radio-collared brown bears were in impoundment-impact areas (Table 19). Even without prevalent over-wintering berries,the same pattern was evident in spring 1981.Excluding females with newborn cubs which tend to remain at high elevations throughout the year,8 (62%)of the radio-collared bears were located in impoundment- impact areas in spring 1981 (47%including females with newborn 55 Table 19.Early spring use 1 of Devils Canyon and Watana impoundment areas by radio-collared brown bears. BEAR ID (age) MALES Bear visited impoundment area?l (No.observations in/total observations) Spring 1980 Spring 1981 Mean elevation of observations in impoundment area (S.D.) 1980 1981 G342 (2) G293 (3) G214 (4) G280 (5) G308a (6) G294 (10) no (0/4) yes (2/4)(to Watana) no (0/3) no (0/2) yes (4/4)(to Devils) no (0/4) no (0/1) yes (10/16)(to Watana) no (0/3) 2038(-) 2030(331) 1721(344) sub totals (6/17) FEMALES (10/24) sub totals (8/30) total (13/37) G335 G281 G340 G308b G344 G331 G341 G313 G277 G312 G334 G283 G299 G337 (2) (3) (3) (5) (5)* (6) (6) (6) (10) (10)* (10) (12)* (13) (13)* yes (3/5)(to Watana) yes (1/5)(to Devils) no (0/5) no (0/4) yes (1/4)(to Watana) yes (3/5)(to Devils) no (0/2) no (0/20) yes (9/26)(to Watana) yes (9/26)(to Watana) yes (6/7)(to Devils) no (0/6)w/2 cubs yes (1/8)(to Watana) yes (12/17)(to Watana) no (0/10) no (0/10)w/2 cubs yes (1/22)(to Watana) no (0/9)w/2 cubs. yes (4/10)(to Watana) no (0/7)w/3 cubs. (42/178) (52/202) 2025(-) 1350(-) 1750(-) 2500(-) 2119(254) 2083(301) 1863(309) 1850(-) 2160(474) 2525(-) 2063(103) - 1 Defined as within 1 mile of impoundment prior to 19 June. *Females with newborn cubs tend to remain at high elevations throughout the summer. _.56 - - - ~. .... '"'" - .... ..... -cubs)(Table 19).Of these 8 bears,7 utilized the Watana impact area and 1 the Devil's Canyon area (Table 19).The mean eleva- tion of the spring observations within the Watana impact area was 2101 feet,below the high water line of the proposed Watana impoundment (Table 19).Excluding females with cubs,52 of the 170 spring locations (31%)in 1981 were in impoundment-impact areas,the same percentage as in 1980. These data represent minimal values for early spring use of impoundment-impact areas by brown bears in the study area.Other bears could also have utilized these areas without having been found there during weekly monitoring flights.Thi sis particu- larly true for bears relocated relatively infrequently'in the spring.For example,G280 was not found in the impact area during three 1980 spring observations but was on 10 of 16 spring observations in 1981,a similar pattern was evident for G299 (Table 19). Lumping both years,these minimal values of brown bear spring use of impoundment-impact areas (conservatively defined)indicate that 14 of 25 bears (56%)utilized impoundment-impact areas and that 66 of 217 observations (30%)made in the spring were in impoundment-impact areas.Ten of these 14 bears used the Watana impact area (71%).The mean elevation of these observations was below the proposed Watana impoundment elevation (2200 feet) suggesting that the Watana impoundment will have a relatively greater impact on spring brown bear habitat than the Devils Canyon impoundment. Females with newborn cubs tend to remain at high elevations,away from the impoundments,during the whole year.Two bears (G283 and G344)that were alone in 1980 but had newborn cubs in 1981 used impoundment-impact areas in 1980 but not in 1981 (Table 19). Two other bears (G337 and G344)with newborn cubs in 1981 also avoided impact areas in 1981,these bears were not radio-collared in 1980.We suspect that in 1982 when the cubs of these females 57 will be yearlings,these bears will return to using impoundment areas in early spring.A possible reason for this behavior by females with newborn cubs is to avoid the areas where other bears concentrate thereby reducing the possibility of intra-specific predation on their cubs.Females with young have been reported to be highly intolerant of other bears,especially males,at McNeil River,AK.(Egbert and Stokes 1976). Ofl 5.Proximity Analysis -Brown Bear Point locations falling within the area of the proposed impound- ments,1 mile from the impoundment shoreline,and 1-5 miles from the shoreline were tabulated (Table 20 &Figure 3).The area of each of these 3 zones was determined (see methods section).The null hypothesis that the number of points that fell in each zone was in the same proportion as the relative area of each zone was tested by Chi square analysis in order to evaluate bear selec- tivity for each zone (Table 20).One assumption of Chi square analysis was violated in this test as the observation were not independent of each other as the data set was composed of mul- tiple locations of the same individuals.Regardless,these data verify the use patterns discussed elsewhere.As mentioned above, female brown bears accompanied by newborn cubs tend to remain at high elevations away from the impoundments and were excluded from this analysis (Table 20). Lumping data for all seasons the null hypothesis was rejected (p<0.005)for each impoundment and for both impoundments consi- dered together.In all cases observed use in the actual impound- ment area was greater than expected (Table 20).Similarly,ob- served use was less than expected in the outermost (1-5 mile) zone (Table 20).This pattern held also for each of the 2 sea- sons considered,but was much more marked in spring (1 May-30 June)than during the rest of the year (Table 20). 58 -. - -I, Table 20.Number of observations of radio-collared brown bears within nested impoundment proximity polygons.Expected values given in parenthesis. Within impoundment Within 1 mile 1 - 5 miles Totals zone but outside impoundment zone >5 miles Chi Square (2 d.f) DEVILS CANY2N IMPOUNDMENT area (km)28.92 %3.28 164.78 18.67 689.01 78.06 882.71 100.00 Females w/o cubs 7/1-4/31 1 5/1-6/30 3 1 7 16 8 18 18 14 11 Males 7/1-4/31 5/1-6/30 subtotal o 2 6 (1.67) o 4 12 (9.52) 6 6 3 9 33 (39.81)~ 19 3 47 13.05* - Females with cubs 0 WATANA IMP02NDMENT area (km)159.32 %9.26 o 327.07 19.02 2 1233.51 71.72 2 1719.00 100.00 10 Females w/o cubs 7/1-4/31 7 5/1-6/30 25 8 15 29 56 44 96 36 62 Males 7/1-4/31 5/1-6/30 subtotal 6 10 48 (17.13) 1 3 27 (35.19) 14 21 11 24 110 (132.68)185 8 10 116 61.41* 3218 2,602.61 100.00 17 1922.52 73.87 1 491.85 18.90 Females with cubs 0===-"---------------....;;,,;,,...----.....;;;.;;~----.;;.;;..--------BOTH IMPO~MENTS area (km)188.24 %7.23 Females w/o cubs 7/1-4/31 8 5/1-6/20 28 9 22 45 64 62 114 50 73 Males 7/1-4/31 5/1-6/30 subtotal 6 12 54 (17.06) 1 7 39 (44.60) 20 27 14 33 143 (174.33)236 27 13 163 86.32* 11.69* 89.82* 77 86 65 (65.74)89 78 (l08.59)147 10 (16.82) 29 (27.78) 14 (6.43) 40 (10.63) Females with cubs 0 1 19 20 42Malesandfem-a":'"l-e-s---------------'--------'-'---------'--------- w/o cubs 7/1-4/31 5/1-6/30 *Significant,P <0.005 59 These analyses reveal brown bear selectivity for the impoundment area throughout the year,this selectivity was especially evident in the spring when observed use was 4 times greater than expected values under the null hypotheses. 6.Impact of Borrow Areas--Brown Bears Brown bear populations or movements will be influenced by some of the proposed borrow areas.Thi s impact would result from the disturbance which borrow area excavation would cause to indivi- dual bears as well as from losses of habitat used by some indivi- duals.Borrow area C (upper Tsusena Creek)would have the great- est impact on brown bears as it occurs in the center of prime brown bear habitat in an area utilized by some individuals espec- ially during the spring and late summer.Other individuals using Tsusena Creek as a north-south transportation corridor would also be displaced.Borrow areas A,H,D,F,and B would also cause some displacement of individual brown bears whose home ranges overlap these sites.Borrow area E (in the riverbed downstream of Tsusena Creek)is in a spring foraging area and would result in di splacement of some brown bear during the period of exca- vation disturbance;over the long run the habitat in this area would likely be vacated by brown bears regardless of the borrow area because of its proximity to the Watana dam site and flooding by the Devi 1s Canyon Dam. VI I I.F.HABITAT RELATIONSHIPS -BROWN BEAR 1.Aeri al Classifications The vegetation type where a bear was found when located from the air was recorded.These data do not show selectivity because no index of availability of the vegetation classifications types was made.However,these data are useful in contrasting different 60 - - - - ,- - groupings of bears by seasons,sexes,or family status. Vegetation type was classified into 1 of 23 classification cate- gories (see materials and·methods section)for 518 brown bear locations made from the air.For 81 of these locations (16%),2 vetation type categories were recorded yielding a total of 599 vegetation type hits for brown bears.These data were lumped into 5 gross habitat categories to facilitate interpretation based on this small sample of hits.These data by month of ob- servation are given in Table 21.Table 21 also includes 85 vegetation type observations for uncaptured bears observed during radio-tracking flights. Brown bear use of spruce vegetation types,which are concentrated around and in the proposed impoundments,was highest in May and June (Table 21).Bears tended to move to shrublands at higher elevations later in the summer.In winter (October-April)71%of the observations were in the "other"category (Table 21);these were mostly snow or rock. These observations were lumped to contrast vegetation type use in the "spring"(1 May-30 June)with those during the rest of the year in order to examine the hypothesis that brown bears use the spruce types near the impoundments relatively more at this time than during the rest of the year.The relatively higher use of spruce vegetation types in the spring was significant (Chi square=10.3,Id.f.,p~0.005).This pattern would have been even more significant if females with newborn cubs were excluded from the analysis.As mentioned above,these bears tend to remain at high elevations away from the impoundment throughout the year following birth of their litter;of 68 vegetation type hits for such bears only 1 was in spruce (49%were in shrublands, 35%in other,10%in tundra,and 4%in riparian). 61 Table 21.Number of aerial brown bear observations by month in each of 5 habitat categories. 62 - - 2.Vegetation Map Classifications -Brown Bear Theoretically,the vegetation maps prepared by the Ag.Expt. Station under contract to TES should permit analyses of bear selectivi ty for different types.Thi sis because the area of each vegetation type can be determined from these maps and fre- quency of bear occurrence in each type can be compared with the relative availability of this type (Table 22). As discussed in the methods section,data on bear occurrence in these vegetation types were obtained by overlaying the location data on the 1:63,360 scale vegetation maps.When a point fell on the border between two types,both were recorded as hi tSj this yielded more vegetation type hits than observations.These data are presented in Table 23a. These data were not statistically analyzed because the only availability information for the 1:63,360 scale maps did not sub- divide the study area.The availability data shown in Table 22 lumped all types throughout the study area,from the Indian River on the west to the confluence of the Tyone River and Tyone Creek on the east.Large differences in availability of different types occur over this distance.Spruce and deciduous trees,for example,are much more prevalent in the western portion while tundra and shrubland types are more prevalent in the eastern portion.Calculated values for expected frequency of occurrence, correspondingly,would not be meaningful.An attempt to appro- priately partition the vegetation map to obtain meaningful availability data using a sampling scheme on the vegetation maps is underway and will be reported later.Even once this is done, however,the analysis may not be particularly useful because of the likelihood that the vegetation types that are meaningful to persons making maps from air photos may not correspond with the habi tat types that are meaningful to bears or other wi ldlife. Some statistical analysis was possible based on vegetation types 63 Table 22.Availability of different habitat types (hectares)based on vegetation maps prepared by Plant Ecology sub task (Ag.Expt.Station,Univ.of Alaska). 11:63,360 TYPE (Code II)Hectares %total area TYPE 21:24,000 scale Devils Canyon Impoundment Watana Impoundment Hectares %Hectares % TUNDRA. Mat and cushion (3) Sedge-grass*(4) Sedge-shrub*(5) Wet sedge-grass (6) Subtotal CONIFER FOREST Open black spruce (7) Woodland black spruce (8) Open white spruce (9) Woodland white spruce (10) Conifer subtotal DECIDUOUS FOREST Closed birch (11) Open birch (l2) Closed poplar (13) Open poplar (14) Deciduous subtotal HIXED FOREST Closed conifer-decid.(15) Open conifer-decid.(16) Mixed subtotal Forest subtotal SHRUB LANDS Closed tall (17) Open tall (18) Birch .(l9) Willow (20) Low shrub (21) Shrub land subtotal GRASSLAHD (22) VEGETATED TOTAL 63,633 27,505 20,073 3,517 114,728 28;304 62,993 10,460 13,291 115,048 2,324 1,498 571 4,393 13,226 9,639 22,865 142,346 15,767 15,524 42,880 8,230 94,863 177 ,264 1,079 435,377 13.76 5.95 4.34 0.76 24.81 6.12 13.62 2.26 2.87 24.88 0.50 0.32 0.12 0.95 2.86 2.08 4.94 30.78 3.41 3.36 9.27 1.78 20.52 38.34 0.23 94.16 Woodland spruce (8 &10) Open Spruce (7 &9) Poplar (13 & 14) Tall shrub (17 &18) (continued) o o o 12 12 162 862 1024 470 73 17 560 758 300 1058 2642 19 58 16 6 99 2753 o o o 0.33 0.33 4.50 23.92 28.42 13.04 2.03 0.47 15.54 21.04 8.33 29.36 73.33 0.53 1.61 0.44 0.17 2.75 76.4 o o o 100 100 4766 3854 8620 491 318 2 811 869 1329 2198 11,629 580 474 55 785 1894 13,623 o o o 0.63 0.63 30.09 24.33 54.42 3.10 2.01 0.01 5.12 5.49 8.39 13.88 73.42 3.66 2.99 0.35 4.96 11.9~ 86.01 ••J J .s I J I J J I J 1 Table 22.(cont'd) J ]j 1 j J ]]]i ~ 11:63,360 16,603 3.59 249 0.05 5,891 1.27 24 0.01 4,236 18 0.01 27,OU 5.84 462,398 100.00 TYPE (Code /I) OTHER Rock (1) Snow and ice (2) Lakes (23) Dist'urbed (24) River-gravel bar (25) He rbaceous (26) Other subtotal TOTAL AREA MAPPED Hectares %total area 1:24,000 scale 2 Devils Canyon Impoundment Watana Impoundment TYPE Hectares %Hectares % 14 0.39 63 0.40 --- Lakes &Rivers (23 &25)836 23.20 2153 13.59 -------- 850 23.59 2216 "13.99 3,603 100.00 15,839 100.00. 0"1 U1 1 Data available permit no breakdown by impoundment,area mapped includes an approximate 5 mile strip on either side of the river along the whole study area.Smallest map unit at 1:63,360 is 7-8 hectares. 2 Smallest map unit at 1:24,000 is about 4 hectares. Bcale. Area to be inundated by proposed impoundments mapped at this Table 23a.Number of radio-collared brown bear observations in different vegetation types mapped at the 1:63,360 scale.Statistical analyses based on these data were not conducted because of absence of appropriately partitioned availability information (see text). Vegetation type TUNDRA Mat and cushion (3) Sedge-grass (4) Sedge-shrub (5) Wet sedge-grass (6) CONIFER FOREST Open black spruce (7) Woodland black spruce (8) Open white spruce (9) Woodland white spruce (10) DECIDUOUS FOREST Closed birch (11) Open birch (12) Poplar (13 &14) MIXED FOREST Closed conifer-decid.(15) Open conifer-decid.(16) SHRUBLANDS Closed tall (17) Open tall (18) Birch (19) Willow (20) Low shrub (21) GRASSLANDS (22) OTHER Rock (1) Snow and ice (2) Lakes (23) Disturbed (24) River-gravel bar (25) Herbaceous (26) Total No.observations with 2 hits (%of observations) No.brown bear hits 42 19 14 4 51 46 22 17 2 2 o 28 8 9 39 48 13 83 1 19 o 1 o 2 1 471 140 (42%) ..... No.observations outside area mapped at 1:63,360 (%of observations) 66 134 (29%) in the actual impoundment area as the availability data presented by the Plant Ecology Subtask presented these data separately for each impoundment (Table 22).Some errors are inherent in this analysis as this availability data was derived from 1:24,000 scale maps.At this scale higher resolution was possible than for the bear use data which was derived from the 1:63,360 scale maps. In the area f,looded by the Watana impoundment,significant brown bear selectivity for the vegetation types categories mapped was revealed by this analysis (Chi square =6.0,4 d.f.,P <0.10). (Table 23b).The mixed conifer-deciduous forest types was the only category utilized more than expected based on availability (Table 23b).Only 63 vegetation type hits were recorded in the Watana impoundment,to be meaningful the number of observations must be large enough to avoid extreme lumping of different types and also large enough to permit separate analyses by season. VIII.-G.DEN AND DENNING CHARACTERISTICS-BROWN BEAR ..... 1980/81 den sites were located and measured for 13 radio-collared brown bears,an additional 3 dens were located for unmarked individuals (Table 24).1981/82 den sites have been tentatively located,from fixed-wing aircraft,for 13 brown bears.Locations of brown bear dens are ~hown in Figu~e 5. Brown bear den sites ranged in elevation from 2,330 to 5,150 feet,the average elevation of 29 dens was 4,181 feet (S.D.=757 feet).Typically brown bears in the study area denned on moder- ately sloping southerly exposures (Table 24,Figure 6).Their dens were dug in gravelly soil and no evidence of reuse of the-previously used den was observed (Table 24).No radio-collared brown bear dens observed to date would be inundated by the pro-..... posed impoundments . .- 67 Table 23b.Brown bear use of vegetation types in Impoundment areas. Watana Impoundment Devils Canyon Impoundment %occurrence on No.hits No.Hits %occurrence on No.hits No.hits 1:24.000 scale observed expected 1:24.000 scale observed expected HABITAT TYPE (1:63.360)-(Other,not (2)(1)! included) 7 &9 (Open 28.50 15 18.00 31.45 2 -Spruce) 8 &10 (Wood-35.24 21 22.2 5.91 0 ~, land Spruce) Conifer Totals 63.74 36 40.20 37.36 2 11-14 (Decidu-6.00 2 3.8 20.43 1 ous Forest) 15-16 (Mixed 16.25 17*10.2 38.60 3 Forest) Decid &Mixed Totals 22.25 19*14.0 ., 17-21 (shrub-14.01 8 8.8 3.61 0 lands) TOTALS 100 %(13523 ha)63 63 100%(2741 ha)6 *Observed greater than expected suggests positive selection. ..... 68 ~g 1 J 1 ")•j J B Table 24.Characteristics of brown bear dens in the Susitna study area during winter of 1980/81. ENTRANCE CHAMBER Total Previously Den Bear Age at Elevation Slope Aspect Ht.Width Ln.Width Ht.Length Used? No.lD No.Exit (Feet)(Degrees)(True N.)Vegetation (em.)(cm.) (em.)(cm.) (em.) (em.)(Yes/No)Comments DUG DENS FE~1ALES With offspring (@ exit) w/2 cubs 14 G283(sp.)13 3900 28 192 Tussock grass -83 -138 -196 No Spring den/collapsed w/2 cubs 16 G283(wt.)13 3725 26 210 Willows 76 64 239 203 92 291 No Winter den w/l cub 22 G313 10 5150 35 166 Tussock/rock slide ---104 -410 No Collapsed w/3 cubs 24 G337 13 4825 31 252 Tussock/lg.rocks 57 69 -152 90 219 No w/2 cubs 30 G344 5 4760 -153 ------ ---Collapsed/not visited w/2 cubs 31 G3l2 11 4900 -145 Tundra/rock -------Collapsed/not visited w/2 ylg.*25 G277 11 4925 45 93 Moss/rock slide ---165 -207 No Collapsed w/2 @2yr.28 G299 14 4660 25 138 Tundra/rock ------No Collapsed w/o offspring 23 G28l 4 4700 39 142 Tussock/rock slide -61 ------"No Collapsed~ 5 G308b 6 2330 26 358 Alder 69 82 112 112 110 230 No ~1ALES 1 G280 6 3950 32 158 Tundra/grass/rock 48 86 -231 -269 No Collapsed 15 G284?3 3990 23 216 Tundra/grass 56 83 135 154 77 239 No ID uncertain 29 G294 11 2650 30.146 Alder/grass 52 80 -157 89 188 No Partially collapsed UNK.SEX/Ill 17 --3925 33 192 Willow 61 62 154 162 122 220 No 26 --4090 29 162 Willow/grass 73 65 --.-171 No Partially collapsed 27 --4125 26 140 Willow/grass -58 --68 -No Partially collapsed *Entered den with 2 yearlings,shed collar in den so exit not observed. - - .~ -III Uo -' -o GO Co -III .. lIS II) ,Q C ~o.. .c "C ;::) o- o CO (I)... .. Gl IIlI U IIlI-.- .. lG II) ..a o.. "0 '":t: I :lIrn C ...... III.. II)-II) E o 10 O<l Cl:I•E u ( \ G277,9r dug cavity natural cavity ------------------- I I I I 1 I I I I I I I 1 I 1 I I-----,.,,'". .-'-.--.-'- .-.-'- """" - .-Figure 8.Aspect of brown bear dens in the Su-Hydro study area.1980/81. 71 Den sites for 8 brown bears were found in both years of the study,the mean distance between dens utilized by the same in-JII!!iIW1! dividual was 4.4 miles (range=1.9-8.9,5.D.=2.7 miles) (Table 25).No brown bear reutilized the same den site but one individual (G337 with/3 cubs)apparently visited her 1981 den prior to denning elsewhere in 1981/82. Radio-collared brown bears in the study area entered dens in Oc- tober and exited dens,in 1981,in late April-early May (Table 26).Based on earliest and latest possible den entrance and exit dates of radio-collared individuals,brown bears spent a median period of 187 days in 1980/81 dens (Table 27),51%of the year. In 1981,brown bears appeared to enter dens earlier than they did in 1980 (Table 26),this may have resulted from the apparent re- latively poor berry crop in 1981;fall weather conditions appear- ed essentially equivalent in 1980 and 1981.Reportedly,brown bears remain out of their dens into December on the Tok1at and Shushana Rivers (just north of Denali National Park)in order to take advantage of a late run of 50,000 chum salmon (M.Chihuly, pers.comm.).If so,this suggests that den entrance dates may be a function of food avai labili ty. For the 14 brown bear dens we visited slope wa:s 31°(range=23-45°,S.D.=6°). dens,13 (81%)were wi thin 45 °of due 24). in summer 1981,the mean (Table 24).Of these 16 south (135-225 0)(Table - ""'", The primary impact of the proposed project on brown bear denning appears,at this point,to be an indirect one resulting from increased di sturbance of den sites by construction activi ties, access routes,transmission line corridors,and increased human activi ty.Craighead (discussion in Lentfer et a1.1972)points out that in Yellowstone National Park,brown bears avoid selecting dens in areas where human activity is substantial. Disturbance can also cause bears to abandon their dens (Reynolds et ale 1976).It is probable that brown bears in the 5usi tna 72 - ~, .... .... Table 25.Distance between den sites utilized by radio-collared brown bears in 1980/81 and in 1981/82 and approximate elevations of 1981/82 dens. Bear In/sex/age Distance Approx.Den elevation (ft.) 1981 (miles)(1981/82) G283/F(w/lc)/13 3.2 4300 G281/F/4 1.9 4900 G280/M/6 8.1 3850 G312/F(w/lc)/11 2.1 4950 G313/F/10 4.4 4750 G299/F/14 8.9 3400 G337/F(w/3c)/13**3.4 4900 G344/F(w/2c)/5**3.1 4350 G335/F/2**?3800 G342/M/2**?2350* G341/F/6**?4400 G340/F/3**?4700 G331/F/6 ?4000 *Emigrated outside of main study area **Not radio-collared in 1980,den site either not known or found during early spring 1981 capture 73 Table 26.Den entrance and emergence of individual radio-collared brown bears,in both 1980 and 1981. Bear ID/sex 1980 * den entrance 1981 * den entrance 1981 entrance earlier 1981 * or later than 1980 emergence - G280/M G281/F G283/F G293/H G299/F G312/F G313/F G331/F G334/F G335/F G337/F G340/F G341/F G342/M G344/F G277 /F G294/M G308b/F 10/13-10/27 10/13-10/27 10/9-10/27 10/9-? 10/13-10/27 9/29-? 9/29-10/9 ?-10/27 ?-10/27 10/~3-10/27 9/22-10/1 10/1-10/7 10/1-10/7 9/22-7 10/1-10/7 10/1-10/16 10/7-10/16 10/7-10/16 10/1-10/7 10/1-10/7 10/7-10/16 10/1-10/7 ?-10/30 10/7-10/16 earlier earlier earlier earlier Later ? 4/7-4/21 4/7-4/21 4/30-5/5 7-5/30 4/7-4/21 4/30-5/6 4/21-4/24 5/8-5/15 4/21-4/30 4/30-5/5 - """ - *Dates indicate last observation away from den and first observation at the den, large gaps,especially in 1980,reflect flights missed due to poor flying conditions. 74 - J 1 i J 1 l:I i j 1 ))1 -1 I 1 J 1 Table 27.Den entrance and emergence dates of radio-collared bears,Susitna Hydroelectric Project.("S"is an index of variability calculated identical to a standard deviation). Possible Days in 80/81 Den Bear ID Sex 1980 Entrance*1981 Emergence*Minimum Maximum Midpoint Comments BROWN BEARS G280 M 13 Oct.-27 Oct.7 April-21 April 162 190 176 G281 F 13 Oct.-27 Oct.7 April-21 April 162 190 176 G283 F 9 Oct.-27 Oct.30 April-5 May 185 208 197 2 cubs in 1981 G294 M prior to 27 Oct.21 April-30 April 176 '1 G299 F 13 Oct.-27 Oct.7 April-21 April 162 190 176 with 2 @ 2 yr.in 1981 G308 b F 13 Oct.-27 Oct.30 April-5 May 185 204 195 G312 F 29 Sept.-'1 30 April-6 May 'l '1 -2 cubs in 1981 G313 F 9 Sept.-9 Oct.21 April-24 April 194 207 201 1 cub in 1981 G277 F prior to 27 Oct.'1 '1 '1 -collar shed in denx=175 198 187 "s"=13 9 12 BLACK BEARS B287 M 9 Sept.-29 Sept.3 April-5 May 186 238 212 B289**F 9 Sept.-29 Sept.8 May-IS May 221 248 235 3 cubs in 1981 B290 F 1 Oct.-9 Oct.5 May-10 May 208 221 215 -....J B301**F 29 Sept.-13 Oct.9 May-29 May 208 242 225 2 cubs in 1981lJ1B303M'1 30 April-5 May '1 '1 B304 M '1 5 May-10 May '1 '1 B317 F 9 Sept.-29 Sept.5 May-IS May 218 248 233 with 2 y1gs.in 1981 B318 F 29 Sept.-13 Oct.30 April-S May 199 218 209 with 1 y1g.in 1981 B319 M 29 Sept.-13 Oct.30 April-S May 199 218 209 B321 F 9 Sept.~29 Sept.10 May-IS May 223 248 236 2 cubs in 1981 B322**M 9 Sept.-13 Oct.'1 '1 '1 -collar shed in den B323**M 29 Sept.-13 Oct.6 Hay-8 May 205 228 217 B324 M 29 Sept.-13 Oct.30 April-S May 199 218 209 B325 F 29 Sept.-9 Oct.'1 '1 '1 -collar shed in den B327**F 9 Sept.-29 Sept.8 May-10 May 221 243 232 with 2 y1gs.in 1981 B328 F 9 Sept.-29 Sept.21 May-29 May 234 262 248 2 cubs in 1981x=210 236 223 "S"=14 15 13 *Range given for entrance is the last observation outside den and first observation inside den,visa versa for emergence ~~*Black bears denning in the impact area of the Watana Dam site,others within the Devils Canyon impact area. area will be similarly displaced from some areas where denning currently occurs as a result of the increased human presence during and following construction of the proposed impoundments. These data on brown bear denning sites generally correspond with s~udieselsewhere in Alaska (Lentfer et ale 1972,Reynolds et ale 1976,Spencer and Hensel 1980).On Kodiak Island and in north- eastern Alaska,however,some dens were found in natural rock chambers or caves (Spencer and Hensel 1980).Additional data in the study area may reveal similar dens. VIII."'"H.PREDATION RATES-BROWN BEAR Brown bears were shown to be significant predators of moose calves in a 1978-1979 study conducted in the headwaters of the Susitna River and nearby study areas (Ballard et ale 1981).Of 123 calves with normal cow-calf bonds subsequent to collaring, 55%died of natural causes (including predation).Of these deaths,brown bear predation accounted for 79%,wolf predation for 3%,unknown predation for 4.5%,and miscellaneous causes for 13.5%.In related studies of 23 radio-collared brown bear in- tensively monitored twice/day in spring 1978,14 (61%)were ob- served on at least 1 calf moose kill (maximum=9 calf moose kills) (Spraker et ale 1981,Ballard,et ale 1981).In this study,a total of 37 calf moose,28 adult moose,4 unidentified moose,3 caribou,and 6 other species were taken by brown bears yielding a total of 1 ki 11/5.6 observation-days'(1 moose/6.3 observation- days)(op.cit.).The maximum kill rate was 1/2.2 observation- days for a 12 year-old solitary female bear.No significant dif- ferences between kill rate and age or family status of the indi- vidual bears could be shown (op.cit.). The results of thi s study are compared with the results of in- tensive (daily)spring monitoring of 8 brown bears in the Susitna study area in Table 28.During this period monitored brown bears killed 3 moose calves (all by the same bear,a subadult female), 76 ....., -. - - ..." - ~- - J I j l I J J J )1 .'j 1 J 1 D 1 I Table 28.Comparison of radio-collared brown bear predation rate data in the Nelchina and upper Susitna River Basins from 26 May to 1 November 1978 and from 21 May to 23 June 1981.(1978 data from Spraker,et al.1981). No.of Prey Bear Family observation Moose Adult Unidentified Adult Obs. Number Sex-age (yr)Status days calves caribou Beaver Misc.a Total days/killmoosemoose 1978 Study 200 M-7.5 single 5 0 0 201 M-1O.5 single 20 2 1 3 6.7 202 F-8.5 single 25 5 1 6 4.2 204 F-8.5 w/2 (1.5 yrs)25 2 1 3 8.3 205 M-4.5 single 29 3 6 9 3.2 206 F-13.5 single 31 2 2 4 7.8- 207 F-l1.5 w/3(0.5 yrs)23 1 1 2 1l.5 208 F-12.5 single 33 9 4 1 1 15 2.2 209 F-4.5 single 22 2 2 11.0 211 M-4.5 single 16 1 1 16.0 212 F-l0.5 single 17 0 0 213 F-l0.5 single 16 1 1 2 8.0 216 M-l0.5 single 10 1 1 10.0 217 M-3.5 single 17 3 1 4 4.3 -...I 219 F-4.5 single 12 1 1 2 6.0 -...I 220 F-5.5 w/l(1.5 yrs)29 1 1 2 4 7.3 221 F-8.5 w/2(1.5 yrs)28 5 1 6 4.7 222 M-l1.5 single II 1 2 1 4 2.8 225 M-4.5 single 25 1 2 2 5 5.0 227 M-9.5 single 8 1 1 8.0 228 H-7.5 single II 1 1 11.0 231 F-12.5 single 19 1 1 2 9.5 234 F-5.5 w/2(1.5 yrs)5 1 1 5.0 Total 437 37 28 4 3 2 4 78 5.6 1981 Susitna Study 299 F-14 single 6 0 0 340 F-3 single 19 3 2 5 3.8 331 F-6 single 6 0 0 281 F-4 single 13 0 0 280 M-6 single 9 0 0 341 F-6 single 12 1 1 12.0 335 F-2 single 18 2 2 4 4.5 334 F-l0 single 19 0 0 Total 102 3 2 5 10 10.2 a Includes small mammals and unidentified species in 1978,possible and unknown species kill in 1981. 2 adult moose (by another subadult female)and 3 species-unknowns during a total of 102 visual observation-days (Tables 28 and 29). Brown bears were strongly suspected to be on kills in an ad- ditiona13 cases (Tables 28 and 29).Even using these suspected kills,the observed predation rate (1/10.2 days)was lower than in the 1978 study.Including all brown bear observations,radio- collared bears were seen on 4 calf moose,4 adult moose,1 adult caribou,and 3 unknown species,and were observed in 5 additional cases where a kill was suspected but not observed. These data doubtless underrepresent actual predation rates because of relatively infrequent monitoring (dai ly instead of twice daily in the spring)and decreased visibility of kills (because of relatively thicker vegetation in the Susitna study- area).The importance of moose calf predation to brown bears, black bears,and to moose populations should be established through studies of radio-collared moose calves in Phase I I of this study. IX.RESULTS AND DISCUSSION-BLACK BEARS IX -A.SEX AND AGE COMPOSITION OE STUDY ANIMALS-BLACK BEAR The number of black bears captured in connection with Su-Hydro studies in 1980 and 1981 totaled 53.This total includes 5're- captures of bears to replace radio-collars,and 2 recaptures of bears that previously shed their collars (B302 and B325).Two bears shed their radio-collars (B288 and B322),hunters killed 6 bears (B305,B307,B316,B320,B326,and B342b),4 bears died of unknown causes (B291,B300,B~19,B330),1 bear died during cap- ture efforts (B296),and the collar was not replaced on one bear during recapture because of an infected neck (B290).At present, 19 black bears have active radio-collars.A chronological list of bears captured and their current status is presented in Table 30. 78 - - - i ])]J 1 J J 1 1 j 1 Table 29.Predation rates of black and brown bears intensively monitored in May and Jume,1981,Susitna Hydro Proj ect. date,Hay 1981 Bear ID/sex/age 21 22 23 24 25 26 27 29 30 31 date,June 1981 2 3 4 5 6 7 9 10 11 12 13 14 15 16 17 18 19 21 22 23 % visuals V V V V V V V R R V V V V 5 R V V V V V V V V V V R 17/23=74% 12/22=55% 18/28=64% 47/73=64% 6/8=75% 19/22=86"% 6/6=100% 13/22=59% 9/14=64% 12/15=80% 18/19=95% 19/22=86% 102/128=80% 149/201=74% V V V R V '!... R R R V V R R V R V V R R V R R R ALL BEAR TOTALS V V V V BROWN BEAR TOTALS BLACK"BEAR TOTALS V V R V V V V V V V V V V R V R4 V R V R R V R R V 5 R V V V R V V V R R V6 V V 4 V R V V R R V V V V V V V V R V V R R V V R R V V V V4 V R V V V V V V V V R V V V V R R V V V V R V6 V V3 V3 V V V V V R V V V R V R R V V 2 V R R V R V V3 V R V R V V V "V V V V VV V R V V V V V V V V V V V R V V V VI V V V V V B302/M/9 B327/Fw/l@1/6 B342/M/5 G299/F/14 G340/F/3 G331/F/6 G281/F/4 G280/M./6 G341/F/6 G355/F/2 G334/F/10 Adult caribou kill,on same kill thru 5/27 2 Calf moose kill,on same kill on 6/3 3 New kill of calf moose 6 Kill of adult moose with another bear,not including own offspring=possible breeding R =Bear not seen,located by radio signal only 4 Suspected kill (specied unknown) 5 Kill of unknown species V =Bear observed visually Table 30 •.Black bears captured in Susitna Dam Studies as of November 1981 Capture Tattoo Sex Age Wt.Date Frequency Flags Ear Tags Comments 287 M 10.5 225*5/1/80 white 1083/1084 (288)F 10.5 125*5/1/80 white 1095/1083 w/2 ylgs,turgid,collar shed by 8/27/80 239 F 9.5 130*5/2/80 white 1103/1104 w/2 ylgs,turgid,had 3 cubs in 1981 (290)l'8.5 103 5/2/80.blue 1306/1305 w/2 ylgs.turgid.see 8/6/81 recapture (291)M (3.5)73 5/2/80 orange ----Post-capture mortality (296)M (l0.5)227 5/3/80 ------Capture mortality (300)M (7.5)274 5/4/80 orange ----Post-capture mortality 301 F 7.5 115 5/4/80 green 1043/1044 w/1 ylg,turgid,had 2 cubs in 1981 (302)M 8.5 287 5/4/80 blue 1106/1105 collar shed by 8/4/80 303 M 8.5 217 5/4/80 green 1055/1056 304 M 10.5 235 5/4/80 ·orange 1315/1316 (305)M (9.5)217 5/5/80 green Shot by hunter 8/30/80 (30n M 2.5 105 5/5/80 orange 1123/1124 Shot by hunter on 5/17/81 310 M 2.5 85 5/6/80 blue/green 1122/1121 (316)F (12.5)150*5/7 /80 blue ----w/1 newborn &1 ylg.shot by hunter 8/28/80 00 317 F 7.8 133 8/18/80 white 1195/1196 ·w/2 cubs 0 318 F 5.8 126 8/18/80 whit;e 1046/1045 ,w/1 cub.also immobilized in den on 3/81 (319)M 3.8 174 8/18/80 orange 1194/1193 Died summer 1981 (320)M (4.8)200*8/18/80 orange ----Shot by hunter 9/9/80 321 F 10.8 175*8/18/80 white 1243/1244 had 2 cubs in 1981 (322)M 4.8 154 8/19/80 orange 1087/1088 w/324,collar shed in 80/81 den 323 M 2.8 122 8/18/80 orange 1200/1199 324 M 5.8 190 8/19/80 orange 1252/1251 w/322 325 F 11.8 164 8/18/80 white 1191/1192 Collar shed in 80/81 den.see 8/6/81 recapture (326)F (5.8)125 8/19/80 white ----w/2 cubs.shot by hunter 8/28/80 327 F 5.8 118 8/19/80 white 1247/1248 w/2 cubs,also immobilized in den on 3/81 328 F 6.8 150 8/19/80 white 1246/1245 w/303.had 2 cubs in 1981 30311 M 8.8 260 8/19/80 orange ----recapture 329 F 1.3 15*3/23/81 white 1266/1265 w/327 &sibling,w/heavy collar (330)M 1.3 31 3/25/81 orange 1276/1275 w/318,died summer 1981 (342B)M (5.5).165 5/7/81 red CF 1206/1205 cinnamon colo~,shot on 9/15/81 343 M 5.5 184 5/7 /81 red CF 1214/1213 alone,Devil Mountain 346 M 9.5 175*5/9/81 red CF 1226/1184 alone.gaging station 30211 M 9.5 300*5/9/81 red CF 1257/i105 alone,old collar previously shed (29011)F 9.8 160+*8/6/81 --1306/1279 neck infected,collar not replaced 30411 M 11.8 --8/6/81 red CF 1286/1316 collar replaced 32511 F 12.8 150*8/6/81 white CF 1191/1192 old collar preViously shed 303/1 M 9.8 250*8/7/81 red CF 1055/1056 collar replaced 287/1 M 11.8 200*8/7/81 red CF 1083/1084 collar replaced 348 M 9.8 300*8/6/81 red CF 1131/1132 alone 349 F 4.8 170*8/6/81 white CF 1326/1325 alone -I<Weight estimated ( )shed collar or dead bear,/I recapture J J ],.J ,..J J j I ..1 I I J I radio-locationsFiveormore female black bears.Numbers were obtained for 14 male and 11 of radio-locations for each in- dividual,and current status,are given ,in Table 31.Of the total of 619 radio-locations of collared black bears,52%were of males (Table 31),comparable to the proportion of males in the study'area sample (Table 32).The age structure of the sample of radio-collared individuals (Table 33)was comparable to that of captured bears in the study area but somewhat older than the sub- sample of black bears taken by sport hunters in Unit 13 (Table 32).We suspect this resulted from hunter selectivity for younger,less experienced bears relative to the more random capture techniques used to capture study-area animals.It is also possible that black bear hunters along the road system, where much of the harvest occurs,are sampling a more heavily harvested and,therefore,younger population than exists in the study area.A heavily hunted population being studied on the Kenai Peninsula by C.Schwartz (ADF&G)averaged younger than the Susitna study animals,especially for females (Table 32).Males represented a smaller proportion of study area individuals than they did in hunter kills in Unit 13,probably because of greater vulnerability of males,which range greater distances,to hunters. These data suggest that black bears marked for Susi tna Hydro studies are reasonably representative of the existing black bear population. IX.-B.SPORT HARVESTS-BLACK .BEAR ADF&G harvest data for black bear in GMU 13 are given in Table 34.From 1973-1980,harvests have averaged 66/year (range 48-85) during a 365 day season with a bag limit of 3 bears (cubs and females with cubs excluded from legal bag limit).Males have consti tuted 74%of spring harvests and 65%of fall harvests. Most of the harvest,(74%)occurs in the fall season when bears 81 82 .- J 1 i J 1 J ]I J 'J j 'J J J )J Table 32.Average spring ages of black bear subpopulations in the Susitna area and Kenai Peninsula. (Includes only bears of known sex and that are 2.0 years or older,spring age calculated as xx.5). Data from the Kenai Peninsula fronl C.Schwartz,ADF&G,pers.comm; Subpopulations Males Average Spring Age (Years)(Range)n Females Average Spring Age (Years)....(Range).n Avg. Both Sexes (Years) % Males 00w GMU 13 harvests* 1973-1980 5.6 1980-1981 Su- Hydro studies**6.6 Su-Hydro studies radio-collared bears wi >5 relocations**6.9 Kenai Peninsula studies 1978-1981***6.2 (2.5-18.5)115 (2.5-10.5)19 (2.5-10.5)14 2.5-12.5 45 5.9 8.1 8.0 5.0 (2.5-11.5) (4.5-12.5) (4.5-11.5) 2.5-10.5 60 13 11 42 5.7 7.2 7.4 5.6 66 59 56 52 *Includes all bear (~2 years)aged and sexed,in recent years not all teeth have been sectioned and read **Represents age at first capture ***Based on total bears known to be alive in each of the years of the study (same bear counted more than once).This procedure should yield a relatively older mean age than the procedure used in calculating mean age in Susitna studies Table 33.Sex and age composition of black bears captured for Su-Hydro studies, 1980 and 1981. ..... Age at first capture Not radio-collared or <5 observations Males Females Sex? Radio-collared with >5 observations Males Females Total captures Males Females Sex? 0-1 1-2 2-3 3-4 4-5 5-6 6-7 7-8 8-9 9-10 10-11 11-12 12-13 TOTALS o o 2 1 2 o o 1 o 1 1 o o 8 o o o o o 1 o o o o o o 1 2 25 1 1 o 3 o o 2 2 2 o o 12 o o 1 2 1 2 1 1 2 1 o 12 3 2 2 3 o 1 2 3 3 o o 20 o o 1 3 1 2 1 1 2 1 1 14 25 - a b Includes offspring observed with radio-collared adults in 1980 and 1981. Two radio-collared yearlings were also included as unidentified-sex cubs the preceding year. 84 .... - - are taken incidental to moose or caribou hunts.A mean of only 23%of the GMU 13 black bear harvest has been taken by non- residents. Black bear do not appear to be a highly prized game animal by GMU 13 hunters.The current harvest is well below the sustainable harvest level.At present it appears that few hunters suf- ficiently prize black bear meat or pelts from GMU 13 to charter an aircraft to hunt black bear off the road system;only 35%of the hunters taking black bear during 1973-1980 recorded aircraft as their primary means of transportation (Table 34).However,it is probable that the increasingly restrictive seasons and con- d:L tions for moose and caribou hunting in GMU 13 will result in increased black bear hunting in this area,especially as more hunters become aware of the existence of substantial black bear populations in the uni t. Recorded black bear harvests in the Susitna Hydro-project study area,1973-1980,have averaged 8/year (1-15)(Table 35).In the s1:udy area,as in GMU 13 as a whole,black bear harvests have been increasing in recent years with the largest recorded annual take occurring in 1980.In the study area,the largest harvests have occurred in the most downstream region,on the Susitna River between the Talkeetna and Indian Rivers,the only portion of the study area currently accessible by river boat or highway vehicle. Improved access for highway vehicles and boats resulting from acces's routes open to the public will doubtless increase sport harvests in the study area.Substantially increased hunting pressure will also result.from hunting by proj ect personnel during construction and operation of the proposed proj ects.In downstream portions of the study area this increased hunting is not anticipated to have significant impacts on black bear popu- lations.However,upstream of Devil Creek where acceptable black bear habitat is highly constricted along the main Susitna River corridor,increased hunting will doubtless greatly reduce and could eliminate black bear populations. 85 I J J J J J ~_J .1 c ..~~,1 J J 1 J j 1 J 1 i j 1 I 1 ),1 J J J J .)1 Table 35.Black bear sport harvest*by subregions in the Su-Hydro project study area,1973-1980. Location 1973 1974 1975 1976 1977 1978 1979 1980 Totals Susitna River, Talkeetna to 1 2 4 3 6 6 2 24 Indian River. Susitna River, Indian River to 3 1 4 4 12 Watana Dam Site Incl.High Lk. Susitna River, Watana Dam Site 1 ~'6 1 1 1 5 15 to Big Bend of Susitna. Fog Lakes- Stephan Lk.9 1 1 3 1 2 17 00 Specific -..]Subregion 1 2 1 2 6 uncertain Totals 14 1 9 5 8 10 12 15 74 *Values are minimal,many hunters inaccurately report the location of their kill. Data compiled from ADF&G sealing records. IX.-C.POPULATION BIOLOGY AND PRODUCTIVITY-BLACK BEAR ~I Black bear populations in the study area appeared to be pro- ductive and healthy in the first 2 years of this study.this was somewhat surprising because the study area is situated on the northern limit of black bear distribution (south of the Alaska Range).Apparently,the habitat is adequate even though limited in extent. Eight litters with a total of 16 black bear cubs were observed with radio-collared females in 1980 and 1981,5 of these litters were not first observed in early spring and may have experienced some losses by June-August when first observed (Table 36).Ne- glecting this,the observed litter size was 2.0 (1.3)cubs/litter (Table 36).The observed litter size for 7 litters of yearling bl'ack bears was 1.9 (Table 36). On the Kenai Peninsula,7 radio-collared females had a mean litter size of 1.9 upon emergence from natal dens (compiled from Schwartz and Franzmann 1980 and 1981).erickson (1964)reported a mean litter size of 2.15 Michigan and 1.96 in Alaska.Litter sizes presented by Jonkel &Cowan (1971)ranged from 1.6 for an unproductive population in Montata to 2.6 for a highly productive wild population in Virginia. In the Susitna study area,1 cub in a litter of 2 was lost in May 1981 (with B328),1 was lost from a litter of 3 (with B289)and both were lost from a litter of 2 (with B321)in August 1981 (Table 36).Counting only the 4 litters initially observed by June,4 of 9 cubs (44%)were lost (all in 1981)(Table 36).On the Kenai Peninsula no losses to cub litters have been observed (Schwartz and Franzmann 1980 and 1981). This high rate of cub loss relative to the Kenai study has several possible explanations: 88 - - ..... - - -- 1 J j J ]I J ))1 )l ]I )1 1 1» Table 36.Black bear offspring survivorship 1 and weaning2 ,Su-Hydro studies. Age when first 1980 1981 litter Age of Age of Bear ID observed litter Apr Nay June July Aug Sept litter Apr Nay June July Aug Sept 288 10 ylg.3/3 3/3 3/3 3/3 3/3 *289 9 ylg.2/2 W 0 0 0 0 cub 3/3 3/3 3/3 3/3 2/3 2/3 290 8 ylg.-2/2 W 0 0 0 *301 7 ylg3 -1/1 W 0 0 0 cub 2/2 2/2 2/2 2/2 2/2 2/2 317 7 cub ----2/2 2/2 ylg.2/2 2/2 W 0 0 0 318 5 cub 3 ----1/1 1/1 ylg.1/1 W O·0 0 0 326 5 cub ----2/2 *327 5 cub -- - -2/2 2/2 ylg.2/2 W(l)1/2 W(l)0 0 328 7 cub 2/2 1/2 1/2 1/2 1/2 321 all cub - -2/2 2/2 0/2 0/2 Totals (cubs)7/7 5/5 7/7 6/7 8/9 8/9 5/9 00 \,0 1 #survivors/litter size2W==weaned in that month (II weaned)3 Female 326 shot on 8/28/80,remote possibility that cubs were adopted by B317 *Shed collar or dead bear,no further data 1. 2. Increased cub vulnerability to brown bear predation (brown bears are relatively rare in the Kenai study area and escape habi tats are more widespread). Maximum density of black bears in the Susi tna relative to possible submaximum (possibly resulting from greater hunting pressure)on the Kenai.This might yield relatively greater intra-specific predation on the Susitna.It might also mean relatively lower recruitment pote~tial because of more sa~ turated habitats and absence of acceptable surrounding dis- persal habitats in the study area. 3.1981 cub mortalities observed were atypical,possibly caused - by the apparent relatively poor 1981 berry crop in the Susitna study area (however,no Kenai cub mortalities oc--, cur red in 1981 either,Schwartz,pers.corom.) . 4.Relatively poor black bear habitat in the Susitna area (this is doubtful because the population appears to have a high reproductive potential based on available information on Ii tter sizes,reproductive intervals,and age of first ma- turi ty). - Three black bears with apparent yearling offspring were captured in 1980 (offspring were not captured);2 of these weaned these offspring in 1980 and produced new cubs in 1981 (Tables 36 and 37),a reproductive interval of 2 years.The third bear (B290) relocated its den in April 1980.Perhaps its original den col- lapsed killing its litter;no similar den relocations were ob- served for other bears.I f a 2 year reproductive interval is standard in the study area,B318, B327,and B317 should produce cubs in 1982 (Table 37).A 2 year reproductive interval is the minimum,doubtless additional data will indicate a mean interval of between 2 and 3 years.The mean reproductive interval for an 90 I"i"" »I J j 1 )I J J J -m J »1 Table 37.Reproductive intervals of female black bears radio-collared for Su-Hydro studies. Litter size followed by M=male,F=female,X=unknown sex This bear was captured near its den site on 7 May 1980 with one newborn and one larger bear suspected to be a yearling (this could happen if 316 bred in 1979 and adopted a cub that year so it would have had a yearling and a cub in spring 1980.The suspected yearling could also have been a 2 year-old bear ~hat denned with or nearby its mother.One year intervals have been reported when lactation is interrupted (Erickson 1964,Baker 1912). YEAR IN WHICH OFFSPRING WERE PRODUCED AS CURS 1 1979 1980 1981 1982 1983 Bear ID -- (288) 289 (290) 301 (316) 318 (326) 327 321 328 317 1 '"2...... Spring age of female when first observed litter was produced 9.5 8.5 7.5 6.5 U.S 5.5 5.5 5.5 U.S 7.5 7.5 season first radio-'collared spring,1980 spring,1980 spring,1980. spring,1980 spring,1980 fall,1980 fall,1980 fall,1980 fall,1980 fall,1980 fall,1980 b2Xb2Xb2~ 1X.-2 Xa1Xb,1 a ~~a 2X a 2X a 3Xa 2X a 2Xa IF,1Xa a b )Bear shot by hunter or collar shed,currently inactive litter first observed as cubs litter first observed as yearlings unproductive Montana population was over 3 years and the pe.rcentage of adult females accompanied by cubs was low (15.6%) (Jonkel and Cowan 1971). Three bears produced litters at 5 years of age and 1 bear at 6 years of age (Table 37).Assuming no previous litters and correct aging,these bears became reproductively mature and successfully bred at 4 and 5 years respectively.Only 1 female (ages 2-6)without offspring was captured (B349,age 4,captured in August 1981);this bear will likely have cubs in 1982 if she became sexually active at age 4.On the Kenai Peninsula,.7 females (aged at 4 years)had cub litters (Schwartz and Franzmann 1980 and 1981),suggesting that reproductive maturity may be reached a year earlier on the Kenai.More data are needed to verify this difference,especially considering the imprecision of aging techniques based on tooth cementum·lines.For an unproductive population in Montana,no femalep were observed in .estrus prior to 4.5 years of age and no bears successfully produced litters at less than 6-7 years (Jonkel and Cowan 1971). Available data are inadequate to calculate productivity of the Susi tna-area black bear population,but avai lable data on pro- ductivi ty parameters suggest it does not have quite the re- productive potential of the Kenai population (based primarily on an older age of reproductive maturity)and may have a lower re- cruitment rate (based primarily on higher rates of cub losses). Relative to.the unproductive Montana population,however,the Susitna population appears highly productive,equivalent to productive populations in the midwest.These comparisons are highly speculative at this point. IX.-D.POPULATION DENSITY -BLACK BEAR No reliable black bear density estimates are available from the study area or adjacent areas.Our subjective impression is that 92 ~, - - ..." - i ~ portions of the study area were very densely populated by black bears relative to other Alaskan habitats.The poor berry crop in 1981 and corresponding lack of bear movements for many bears to more open country prevented the aerial census originally planned for August 1981.The only avai 1ab1e data that permit even a crude density estimate come from sightings of marked and unmarked black bears during the August 1980 tagging operation. In 1~days of spotting effort (August 18-19, 1981),35 bears were seen in approximately 259 km 2 of search area,four of these were marked.A radio-tracking effort on August 14 verified the pre- sence of seven radio-collared black bears in the search area.A,- straightforward Lincoln Index on these observations yields an approximation of 61 bears in this area or 1 bear/4.1 km 2 •An "adjusted"index (Ricker 1975)yields an estimate of 58 bears (s.d.=19).These estimates should be viewed cautiously as there are many possible sources of bias in the technique and it covers only a small portion of the study area during only 1 season. Regardless,the density estimate of 4.1 km 2 /bear falls roughly at the mid-point of reported black bear densities in North America and is only slightly lower than .the most intensively studied nearby population (Kenai Peninsula,Schwartz and Franzmann 1981) (Table 38).Our subjective evaluation is that further studies in the Susitna study area are more likely to reveal that the above density approximation is too high in upstream areas and perhaps too low in downstream (Devils Canyon)portion of the study area. A highly speculative estimate of the number of black bears in the study area is possible from this estimation.Assuming that one- third (1,400 km 2 )of the study area (Fig.2)is acceptable black bear habitat,this density would yield a population estimate qf 341 black bears in the study area.This estimate must be im- proved by additional studies,if correct it suggests that only 14%of the black bears in the study area have been captured and that only 6%are currently radio-collared. 93 Table 38.Densities of black bears as estimated in studies conducted in different localities (modified from Modafferi 1978). Source McIlroy (1972)* Lindzey and Meslow (1977) Poelker and Hartwell (1973) Piekielek and Burton (1975) Beecham (1980) Jonkel and Cowan (1971) LeCount (1980) Pelton and Burghardt (1976) Kemp (1972) Modafferi (1978) Schwartz and Franzmann (1981) Erickson and Petrides (1964) Spencer (1955) Clarke (1977) Location Alaska (coastal population) Washington (an island population Washington (mainland population California Idaho (Councial area) Idaho (Lowell area) Montana (Bear Creek) Arizona Tennessee Alberta Prince William Sound,Alaska Kenai Peninsula,Alaska Michigan Maine New York (Adirondacks) New York (Catskill) New York (Allegany State Park) .2 DU. Per Bear 0.1 0.3 0.7-1.0 0.8-1.0 0.8 0.9 0.8-1.7 0.8 0.5-1.0 1.0 1.2 1.5 3.4 5.6 2.6 3.7 10.0 km 2 Per Bear 0.3 0.8 1.8-2.6 2.1-2.6 2.1 2.3 2.1-4.4 2.1 1.3-2.6 2.6 3.1 3.9 8.8 14.5 6.7 9.6 25.9 - - *Probably estimated during season concentration. 94 - - ..... IX.E.HOME RANGE AND MOVEMENTS-BLACK BEARS 1 .Home Range s Home range sizes for Su-Hydro study area radio-collared black bears are given in Table 39 for individuals with 5 or more relo- cations.These home ranges are illustrated in Appendix 2.In 1980,the mean home range for all bears was 31 km2 (16 km2 for females and 46 km2 for males)compared to 218 km2 in 1981 (200 km 2 for females and 234 km2 for males).Mean home ranges in 1980 and 1981 for bears older than 2.0 years are given in Table 40. The data for these two years are not completely comparable as different individuals were observed during different seasons (Table 39).Regardless,it appears that these home ranges tend to be larger than has been recorded for black bears on the Kenai Peninsula:16.7 km2 for females and 98 km2 for males (Schwartz and Franzmann 1981).However,in the Kenai study,a more con- servative method was used to calculate home range sizes.As can been seen by reference to the home range plots in Appendix 2,the home range sizes reported in this study include,for many bears, large areas where no observations were made.This is especially true for the 1981 data when many bears moved long distances in late summer to foraging sites;these home ranges could be viewed as 2 seasonal home ranges connected by a narrow transportation corridor rather than as one home range. Larger home ranges in 1981 relative to 1980 were observed for all groupings of individuals but were significant only for males (PtO.01)and both sexes lumped (PtO.OS)(Table 41).Some of this increase was doubtless caused by the greater number of obser- vations per bear in 1981 (Table 40)but it is evident that home ranges in 1981 were much more variable and larger than in 1980 (Table 40).We suspect that the greater movements in 1981 re- flect the apparent relatively poor 1981 berry crop which neces- sitated greater movements to find acceptable foraging areas. Steve Buskirk (U.of Alaska,pers.comm.)informed us that ber- 95 '-" Table 39.Home range sizes for Su-Hydro study area black bears.(Includes individuals with 5 or more relocations). 1980 1981 Hom2 Range Bear ID Observation Period Home ~nge Observation Period Home ~ange (km)1980 & (age @ capture)(No.of locations)(km )(No.of locations)(km )1981 lumped Comments Males August-October (6) August-October (6) August-October (5) May-October (16) Bear died Bear died Collar shed in '81 recaptured in '82 Colar shed in den Shot by hunter 146 383 400 326 43 10 248* 383* 289* 326* 611* (9) (36) (19)May-October May-July May-September (40) May-October (18) May-October .May-October (14) 4 20 20* 29 10 67(6) (7) (7)May-July May-July May-July 330 (1) 323 (2) 319 (3) 291 (4) 322 (4) 324 (5) 342B(5) 343 (5) 302 (8) 1.0 0"\ May-September~ August-October (7) May-October ~ 303 (8) 305 (9) 346 (9) 348 (9) 287(10) 304(10) May-October May-August May-October (15) (9) (17) 95* 48* 136* ~*.** May-October May-October May-October (18) (16) (15) 92* 62* 388 268* 37* 142 292 51* Killed by hunter ~(all males)=(9.2) S.D. range =(5-17) 46 42 4-136 18.9 18.9 (7-40) (Continued) 230 185 10-611 248 135 51-400 J I J J !I I I J J J J J 1Dj11 1 'J )J 1 1 I Table 39.(Cont'd) Bear ID (age @ capture) 1980 Observation Period (No.of locations) Home ~ange (km ) 1981 Observation Period (No.of locations) Hom~Range Home ~ange (km )1980 & (km )1981 lumped Corruments August-October (6) August-October (6) August-October (6) August-October (6) weaned 2@2 in '81 weaned 1@1 in '80 weaned 2@1 in '81 weaned 2@1 in '81 not recollared in '81 as neck was infected. weaned 1@1 in '81 30 32 163 1051 14*19 15 --weaned in June 1981 12*(w/2c)26 28*(w/2c) 36 31* 116* 1036* (14) May-October (18) May-October (19) May-October (14) May-October (34) August-October (6) May-August May-October (18) May-October (20) 4 (w/2c) 18* 25(w/1c) 3(w/2c) 4 45*(18) May-October (20) May-October FEMALES 329 (1) 349 (4) 318 (5) 327 (5) 328 (6) 301 (7) 317 (7) 290 (8) 1.0 -..J 289 (9)May-October (14)43*May-October (19)26*(w/3c)47 weaned 2@1 in '80, had cubs in 1981. August-October (6) 288 (10) 321(10) May-August (16)7 3 May-October (14)771*(w/2c)774 collar shed lost cubs in August and made big move- ment. x(AII Males &Females)=(9.8)31 S.D.=---35 Range=(5-20)3-136 x(AII Females)=(10.4)16 S.D.=16 Range=(6-20)3-45 Collar shed in 80/81 recaptured in Aug. 1981. 146 254 383 19-1051 251 293 19-1051 117 200 355 6-34··12..;.1036· (16.7) (17.9)215 273 (6-40)10-1036 August-October (8)8August-October ~325(11) *Included in statistical comparisons,Table 41. **Excludes atypical location of 80/81 den,with den home range for 1980 &1981 was 104 km 2 • •J J J J !J I -. Table 41.Statistical comparisons between 1980 and 1981 mean black bear home range sizes. (Only individuals with comparable data in each year are included,see Table GG). 2MeanHomeRange(km ) Comparison 1980 (n)1981(n)T d.f.P(X) males 66(5)257(9)2.34 12 0.98* females 35 (3)254(8)0.91 9 0.81 females (w/o cubs)35(3)1 299(4)2 .91 5 0.80 both sexes 55(8)255(17)1.95 23 0.97** males 303,287, and 304***88 (3)102(3)0.6 4 0.71 female 290 45(1)116(1) *Significant at P<O.Ol **Significant at P<0.05-***Equivalent data available for feasible for females (301 and both years for these 3 bears,similar comparisons not 289)because of presence of cubs in one of these years. .... r i I, r I - 1 2 Includes females 301,290, 289. Includes females 318,327,317,290 • 99 '. ries were relatively infrequent in martin scats in 1981 relative to 1980 and he also believes that a berry crop failure occurred in 1981.In 1981,black bears were observed north of the Denali Highway near Susitna Lodge (R.Halford pers.comm.),a relatively ra,re occurrence which also supports the theory that 1981 was a year of atypically large black bear movements. Black bears usually den wi thin seasonal home ranges.The sizes of home ranges including observations at or in dens averaged only 0.4%larger (0-2%)than home ranges which excluded observations at dens.B304 was excluded from this analysis,his 1980/81 den was in an atypical high-elevation location which resulted in a 105%increase in home range size when this den location was' included in calculation of his home range. Unlike brown bears,data on mean elevation of black bear obser- vations (Table 17)reveal few patterns.Females with cubs maintain a lower mean annual elevation than other bears (T=2.22, PtO.001).The mean elevation of all observations of radio- collared black bears is at the high water mark of the proposed Watana impoundment (2200 feet)(Table 17). The areas of overlap of black bear home ranges with the impound- ment area and with the area enclosed by polygons constructed 1 mile and 5 miles from the proposed impoundment shorelines were determined (see Methods Section).The mean overlap with the impoundment area was 14%(0-45%),with the 1 mile polygon it was 50%(0-100%),and with the 5 mile polygon it was 122%(56-195%) (Table 42).Values over 100%were obtained when a large portion of the home range occurred in the area overlapped by the 5 mile polygons for each dam,the 1 mile polygons did not overlap (Figure 3).These data clearly demonstrate the close association of black bear distrib':ltion with the immediate vicinity of the proposed impoundments. 100 ..... ..... - J J J 1 j 1 J 1 ),-1 D J J 1 .1 J Table 42.Area of intersection of black bear annual home ranges with each impoundment and with 1 and 5 mile impoundment proximity polygons.(Home range data from Table 39). Area of Intersection Area of Intersection Area of Intersection with Impoundment +1 mile +5 miles Bear ID Home Watana Devils Total Watana Devils Total Watana .Devils Total (age)Range (km Z)(km 2 )Canyon %over-(kmL )Canyon %over-(km 2 )Canyon %over- (km 2 )lapped (km 2 )lapped (km Z)lapped MALES 330 (1)10 0 0 0 0 3.5 35.0 1.6 10.0 106.0 323 (2)383 1.0 21.7 5.9 10.3 138.9 39.0 84.7 371.1 119.0 319 (3)146 0 14.1 9.7 0 77 .1 52.8 0.5 145.8 100.2 291 (4)20 0 1.6 8.0 0 9.9 49.5 19.3 19.5 194.0 322 (4)10 2.5 0 25.0 9.0 0 90.0 9.6 2.3 119.0 324 (5)400 0.4 9.8 2.6 9.9 75.2 21.3 39.0 250.2 72.3 342B(5)611 141.4 0 23.1 352.7 0 57.7 569.9 13.7 95.5 343 (5)289 0 11.8 4.1 0 74.6 25.8 0 162.1 56.1 302 (8)326 98.0 0 30.1 199.7 0 61.3 325.4 0 99.8 303 (8)142 0 3.1 2.2 8.2 28.4 25.8 82.9 140.2 157.1 305 (9)48 0 0 0 0 0 0 39.3 11.1 105.0 346 (9)62 14.8 0 23.9 53.1 0 85.6 61.6 0 99.4 348 (9)388 34.3 2.0 9.4 85.9 30.9 30.1 170.2 281.3 116.4 287 (10)292 6.3 2.5 3.0 22.8 42.1 22.2 87.0 258.1 118.2 304(10)104 0 0 0 0 4.3 4.1 57.2 62.2 114.8 FEMALES 329 (1)15 6.8 0 45.3 11.9 0 79.3 14.7 10.9 170.7 349 (4)36 0 11.2 31.1 0 31.5 87.5 0 35.9 99.7 (Continued) Table 42.(Cont'd) of Intersection 1 mile of Intersection 5 miles Bear ID (age) Home Range (km 2 ) Area of with \'1atana (km 2 ) Intersection Impoundment Devils Total Canyon %over- (km 2 )lapped Area + Watana (km2 ) Devils canIon (km ) Total %over- lapped Area + Watana (km 2 ) Devils Canyon (km2 ) Total %over- lapped .318 (5)1051 113.5 4.3 11.2 336.2 35.3 35.3 922.2 124.2 99.6 327 (5)32 14.1 0 44.1 22.3 4.8 84.7 32.0 24.9 177.8 328 (6)30 0 0.9 3.0 5.6 10.8 54.7 28.9 29.5 194.6 301 (7)26 7.0 0 26.9 26.0 0 100.0 26.5 0 101.9 317 (7)19 0 0 0 0.9 5.8 35.3 13.7 19.3 173.7 290 (8)163 0 10.6 6.5 0 69.6 42.7 8.6 163.4 105.5 I-'a I\J 289 (9)47 21.3 0 45.3 37.6 4.2 88.9 46.9 27.3 157.9 288(10)7 0 0 0 0 3.7 52.9 0 7.4 105.7 321(10)774 92.9 5.4 12.7 279.1 46.1 42.0 697.5 154.4 110.1 325(11)146 9.8 3.3 9.0 41.8 28.8 48.4 109.3 83.9 132.3 mean =14.15 50.1 122.3 *Percentage figures do not accurately portray impoundment-related habitat losses as home range size used reflects total annual home range.percentage figures based on seasonal home ranges would.be higher especially during spring and early summer. J J ,I J I J J 1 J ),I J J I J -I 2.Seasonal Movements As mentioned in our first annual report l in 1980 many black bears made seasonal movements in late summer (late July-August)to the tablelands between the spruce forests along the Susitna River and the mountains north of the river (see Figure 7 and Appendix 2). We suspect these movements were motivated by ripening berries which may be more abundant in these relatively open areas than in the spruce forests where black bears are more commonly found during the rest of the year.Similar movements were evident in 1981 but many bears moved much greater distances in this year. We suspect the apparent 1981 scarcity of berries in the table- lands relative to 1980 prompted these more extensive movements which are reflected in comparisons of annual home range sizes (Table 39).These movements are likely motivated by searches for better foraging or fishing areas l but actual motives could not be determined.Details of these,apparently atypical,movements follow for selected individuals. In August-October 1980 1 female 318 (with 1 cub in 1980)remained in the vicinity of Tsusena Creek.After weaning her yearling and apparently breeding in 1981,this bear moved upstream in late July about 80 km to the vicinity of the confluence of the Tyone and Susitna Rivers l returning to Tsusena Creek in mid-September and entering her den in late September (Fig.44). In August-October 1980 and early summer 1981,female 321 (with 2 cubs in 1981)remained in a small home range east of Devil Moun- tain and west of Tsusena Creek.In early August 1981 she lost her cubs and then moved about 64 km upstream to Tyone Creek,retur- ning to her original home range by 9 September and entering her den between 16 and 22 September (Fig.46). The same pattern was apparent for female 325 who had a 1980 home range east of Devil Mountain and west of Tsusena Creek but was found upstream in the tablelands between Watana and Kosina creeks 103 =* =* =* ** * .~~~=****~*_.A*****?***~'r\~~ *~ =* Figure 7.Distribution of 204 black bear locations obtained between 16 July and 4 September.During this period many 'black bears utilize a berry-rich shrubland habitat adjacent to the spruce forests. J I ,I !J - -- - - in August 1981.She returned in early September 1981 and entered her den in late September (Fig.50).This bear shed her collar in her 1980/81 den and so her movements early in 1981,prior to her recapture in August,were not known. Female 290 (with 1 yearling in early 1980)spent the whole 1980 season and e'arly summer 1981 in a small area north of Stephan Lake.In early August she moved upstream about 25 km to the Tsusena Creek vicinity (Fig.36).This bear was recaptured in August 1980 but was not recollared because of an infected neck so her 1981/82 den location was not determined. Male 342b (a large cinnamon-colored bear)made similar upstream movements in 1981,from Tsusena Creek to Vee Canyon in August- September 1981 (Fig.55).This bear was shot by a hunter in September while it was apparently returning. Male 346 spent most of the summer of 1981 just west.of Vee Can- yon,moved wes:t almost to Jay Creek in late July and then moved back east almost to Goose Creek in August,returning to den just west of Vee Canyon.These.movements suggest that an initial westward movement to find better foraging was unsuccessful and was followed by a more successful movement upstream (Fig.57). Male 323 was found between Tsusena .and Deadman Creeks in fall 1980,moved to the High Lake-Portage Creek area in spring 1981 but came back in fall 1981.This bear denned at about the same place (at the proposed Watana dam site)in both years (Fig.48). The reason for the westward movement in spring 1981 is unclear. It is likely,however,that the bear was foraging for berries on the upstream tablelands in the late summer of both years. Three males moved downstream from the main study area in fall 1981,apparently to fish for salmon downstream of Devils Canyon. B343 moved from a home range centered on Devil Creek in early 1981 downstream to about mile 250 on the Alaska Railroad 105 (Talkeetna Mts.Quadrangle C-6)in late July and denned in this same general area.The calculated home range of this bear (Fig. 56),Table 39)cuts diagonally across the Chunilna hills instead of following the Sus'i tna River as the bear doubtless did.In fall 1980,B324 (Fig.49)was found in the tablelands between Tsusena and Deadman Creeks,denned and spent the early summer 1981 between Stephan Lake and east of Devil Mountain.In late July 1981 this bear moved downstream to the same area as B343 but returned to its same den site in late September (interestingly, this den was apparently occupied by female B325 and B324, obligingly,found another den elsewhere).Male 348 (Fig.58)was captured on the tablelands around Watana Creek early August 1981 but moved west to Portage Creek in early September and denned on Portage Creek.Perhaps this bear found his traditional late- summer berry foraging area inadequate and moved west to fish for salmon as a replacement. It appears that female black bears with newborn cubs do not make movements as extensive as other bears even during years of berry scarci ty.Two females that were observed from May through Octo- ber both 1980 and 1981 had smaller home ranges in 1981 when they had cubs than they did in 1980 when they were alone (B289 and B301,Table 39).A third bear (B321),as mentioned above,re- mained in a small 1981 home range until her cubs were lost and then made an extensive movement upstream.The pattern of larger home ranges in 1981 compared to 1980 appeared to be reversed for females with newborn cubs (Table 39),although sample sizes remain too small to be conclusive.If 1981 was indeed a poor year nutritionally for black bears,relatively high losses of the surviving cubs in their 1981/82 dens might occur. The pattern of black bear movements based on available data and supposition can be summarized as follows.In years of normal or acceptable berry crops,many bears move to somewhat higher country adjacent to the spruce habitats along the river in late summer,returning to their spring and early summer home ranges 106 - -. - - - near the river to den.Most of these late summer movements are upstream (east)and a bit north.In years of subnormal berry crops most individuals make more extensive movements and many of these move long distances upstream or downstream in search of acceptable foraging areas or areas where salmon are avai lable. These movements occur both upstream and downstream along the main Susitna River which becomes a main transportation corridor.Some of the individuals making these extensive movements do not return to their former home ranges,but most do.Females with newborn cubs are exceptions to this rule,making less extensive movements than other bears or than themselves in years when they do not have cubs,regardless of the berry crop.In late summer and fall,especially in poor berry years,the more extensive move- ments of black bears may bring them in closer contact with areas frequented by brown bears at time and this may result in increased mortality of black bears through inter-specific predation. 3.Proximity Analysis -Black Bear Proximi ty analyses f9r black bear locations falling wi thin the area of the proposed impoundments,1 mi Ie from the proposed impoundment shoreline,and 1-5 miles from the shoreline were con- ducted in the same manner as di scussed for brown bear (section VI I I-E-5 this report).These data are presented in Table 43. In all cases the null hypothesis that bears were using these 3 zones in proportion to the areas of these zone was rej ected (P~O.025)(Table 43).For the Watana impoundment,both the impoundment area and the area within 1 mi Ie of the impoundment were used markedly more than expected (Table 43).For the Devils Canyon impoundment the zone within 1 mile of the impoundment shoreline showed the highest use relative to expected values (Table 43).The outermost zone most distant from the proposed 107 108 impoundments was used only about half as much as expected under the null hypothesis for both impoundments (Table 43). On a seasonal basis the lowest variation from expected values occurred in the late summer (16 July-31 August).This corres- ponded with the observation discussed above that at this season many black bears tend to move to berry-rich tablelands more dis- tant from the impoundments.Even in the late summer,however, selection for the immediate impoundment vicinity was significant (Table 43). The restriction of black bear distribution in the study area to the immediate vicinity of the·proposed impoundments is clearly evident in this analysis.Only 25 locations (4%)were outside of -the 5 mile impoundment-proximity (Table 43).Most of these 25 locations were in the vicinity of the Susi tna River but were either upstream or downstream of the 5 mile polygon (see Figure 2 and Figure 3),only a few were actually over 5 miles distant from the Susi tna River. This analysis clearly shows that the direct impact from flooding on the area utilized by the existing black bear population will be severe in the vicini ty of the proposed Watana impoundment. 4.Dispersal Di spersal of bears from the study area may contribute to bear populations in other areas.Some black bears may also disperse to the study area but the reverse is probably more common because ~ of the constricted,and apparently saturated,nature of black bear habitat in the primary study area near the proposed impound- ments.Dispersal to the impoundment area cannot be documented because individuals from distant subpopulations have not been ~radio-collared.Some cases of dispersal of marked bears from the study area,however,have been documented.More dispersal from 109 the study area likely occurs than has been documented;problems wi th placing radio-collars on subadul t bears,the most likely dispersers,results in minimal documentation of actual dispersal frequency.Of 4 documental dispersals,3 have been westward and 1 southward. A 2-year old male (B307)was captured on Clark Creek (west of Tsusena Butte)in May 1980.This subadult was marked but not radio-collared.One year later this bear was shot by a hunter near Hurricane on the Parks Highway,about 30 miles west of its capture site.This represents a probable natural dispersal of a subadul t bear. A 4-year old male (B320)was captured in August 1980 north of the Susi tna River and east of Devi 1 Mountain.Without any inter- vening relocations,this bear was shot 1 month later on the Sheep River,45 miles south.Guide Ed Stevenson.·who returned the radio-collar and provided information on the ki 11 location had seen this bear 5 times earlier in September in the upper Sheep River.This represents a dispersal of an adult black bear from the study area,but the possibility that trauma associated with capture contributed to this behaviour cannot be discounted. Similar behaviour,however,has not been seen for other handled bears. As discussed above,3 adult black bear males in 1981 moved down- stream of the Devils Canyon dam site from upstream areas in the vicinity of the proposed impoundments.Two of these bears (B343 and B348)denned downstream ..As discussed,these movements may have been prompted by a scarcity of upstream forage in 1981 but, regardless,represent apparent dispersals from the study area. The implications of these black bear movement patterns relative to the proposed construction of Su-Hydro dams include the fol- lowing: 110 - - - - 1.Actual impoundment areas and impoundment-impact areas will have a negative impact on black bear denning habi- tats and spring-early summer habitats when bears are concentrated along the river in spruce-vegetated habi- tats. - 2. 3. 4. Late summer and fall foraging habitats on the adjacent tablelands will be adversely affected by access routes proposed through them and by construction facilities and borrow areas.A primary tableland area is between Tsusena and Deadman Creeks,the si te of the current Watana Camp and the probable site of expanded quarters for construction staff. During poor berry years movements downstream of the proposed dams by black bear to forage for salmon below Devils Canyon may be unsuccessful because·of reduced or eliminated natural salmon spawning between Talkeetna and Devils Canyon (a needed buffer in bad berry years may not be available).These movements may be typical of some individuals even in moderate to good years,but have not so far been seen except in 1981. Transportation corridors for movements upstream and downstream by bears in the project area may be blocked or constrained by the impoundments themselves,this may be especially important during poor berry years when these corridors are most utilized.Any such impediment would limit seasonal movements to foraging areas in- cluding movements to areas where moose calves may be important prey. - .- 5.Climatic changes resulting from the impoundments may al ter (either beneficial or deleterious effects are possible)the abundance or distribution of berries on the tablelands used by bears in the late summer. 111 6. Similar climatic influences in the immediate vicinity of the impoundments may alter the availability of forage utilized early in the spring,this effect would doubtless be negative. Reduction of the number of dispersing bears to adjacent habitats (long-range). - - 5.Impact of Borrow Areas--Black Bear Black bear populations or movements will be affected by some of the proposed borrow areas. The greatest impact wi 11 be in borrow area D (west of Deadman Creek)which is in the tablelands area used by black bears for- aging for berries in late summer.As mentioned,in the late summer these tableland areas are used both by local resident black bears as well as by bears moving to these areas from down- stream locations.The plant ecology study (subtask 7.12) prepared by the Agricultural Experimental Station,University of Alaska indicates the size of Area D as 228 hectares of which 48% is low mixed shrub and 32%is birch shrub (op.cit.I Table 4, page 23).Bog blueberry (Vaccinium uliginosum),crowberry (Empetrum nigram)and Mt.cranberry (V.vitis-idaea)were especially common in these shrub types according to this study. Borrow area D encompasses 0.02%of the low mixed shrub type found in the entire upper Basin and 0.22%of the birch shrub type (op. cit.).From the perspective of a black bear,however,these low percentages are misleading as the proximity of these types to escape cover (especially forests)governs their use by black bears.Borrow area D encompasses a much higher percentage of these types which are also found in close proximity to escape cover.The same type of impact would result from Borrow area F (mid-Tsusena Creek)which is 77%comprised of the low shrub type. 112 - '""'" Borrow areas B (mouth of Deadman Creek),A (Fog Lakes),H (south of Fog Creek),and the north part of E (mouth of Tsusena Creek) are in forested areas where some individual black bears are resi- dent.Of these,area A would have the least impact on black bears and area H the greatest based on available data.These borrow areas would reduce the amount of black bear habitat available in ,~ the study area.Borrow area C would have negligible impact on black bear. IX.F.HABITAT RELATIONSHIPS-BLACK BEAR 1.Aerial Classifications - - Vegetation type was classified into 1 of 23 classification cate- gories for 724 black bear locations made from the air.For 227 of these locations (31%),2 vegetation type categories were recorded yielding a total of 915 habitat hits for black bears. Of these 798 were obtained from radio-collared individuals. These data were lumped into 5 gross habitat categories as dis- cussed above for brown bears.These data by month of observation are given in Table 44. Black bear use of spruce habitats,concentrated in the vicinity of the proposed impoundments,was common throughout the year but was least prevalent in late summer.In August black bears were more commonly found in shrubland habitats adjacent to the spruce forests (Table 44).As mentioned,we suspect this late seasonal movement was motivated by the relative abundance of ripening ber- ries on these shrubby tablelands. The hypothesis that spruce habitats were used less frequently in late summer (16 July-31 August)was tested by contrasting occur- rence in spruce habitats during this season (36%of 251 obser- vations)with the rest of the year (44%of 547 observations)for radio-collared individuals.The difference was significant (Chi 113 Table 44.Number of aerial black bear observations by month in each of 5 habitat categories • .114 - - - - square =4.7,1 d.f.,PlO.05).There was a significant differ- ence between males and females in late summer use of spruce habi- tats (Chi square =4.4,1 d.f.,PlO.05).In the late summer 43% of 126 female observations were in spruce habitats compared to 30%of 125 male observations .Although sample sizes are small, -this difference does not appear to reflect differences between females with newborns (12 observations in ppruce out of 30 in the late summer)and females without newborns (25 observations in spruce out of 95 in the late summer (Chi square =1.88,1 d.f., P©O.10). 2.Vegetation Map Classifications -Black Bear The techniques and problems involved in use of the vegetation maps prepared by the Plant Ecology subtaskto show bear selec- tivity for different types are described in the brown bear por- tion of this report (Section VI I-F-2).The same problems exist for the black bear data which are presented in Table 45a.As discussed for brown bears,statistical analyses of these data based on existing information on availability of these vegetation types would be inappropriate. As was done for brown bears,however,some analysis of black bear selectivity for different vegetation types within the actual im- poundment area was possible for the Watana impoundment.Wi thin the area flooded-by the proposed Watana impoundment,use of vege- tation types varied from expected values that were based on availability (Chi square =68.1,4 d.f.,PlO.005)(Table 45b). Deciduous forests and shrublands were used more than expected in the flooded area and the other types were used less than expected (Table 45b). In the deciduous category all use was in closed birch (17 hits) and open birch (12 hits).It is noteworthy that 35%of the area of these 2 types will be flooded by the impoundments (calculated 115 Table 45a.Number of radio-collared black bear observations in different vegetation types mapped at the 1:63,360 scale.Statistical analyses based on these data were not conducted because of absence of appropriately partitioned availability information (see text). Vegetation type TUNDRA Mat and cushion (3) Sedge-grass (4) Sedge-shrub (5) Wet sedge-grass (6) CONIFER FOREST Open black spruce (7) Woodland black spruce (8) Open white spruce (9) Woodland white spruce (10) DECIDUOUS FOREST Closed birch (11) Open birch (12) Poplar (13 &14) MIXED FOREST Closed conifer-decid.(15) Open conifer-decid.(16) SHRUBLANDS Closed tall (17) Open tall (18) Birch (19) Willow (20) Low shrub (21) GRASSLANDS (22) OTHER Rock (1) Snow and ice (2) Lakes (23) Disturbed (24) River-gravel bar (25) Herbaceous (26) Total No.black bear hits 13 9 5 9 34 122 21 51 30 21 o 107 33 14 32 125 7 98 o 9 o 1 o o o 741 - - - -, No.of observations with 2 hits (%of observation)216 (41%) No.of observations outside area mapped at 1:63,360 (%of observation)93 (15%) 116 Table 45b.Black bear use of vegetation types in impoundment areas. Watana Impoundment Devils Canyon Impoundment-%occurrance on No.hits No.hits %occurrence on No.hits No.hits 1:24,000 scale observed expected 1:24,000 scale observed expected HABITAT TYPE (1:63,360) ~(Other,not (2)(0) .included) 7 &9 (Open 28.43 17 42.1 31.45 0 Spruce) •.! 8 &10 (Woodland 35.24 52 52.2 5.91 0 Spruce) CONIFER TOTALS 63.74 69 94.3 37.36 !"""" 11-14 (Deciduous 6.00 29*8.9 20.43 0 Forest) 15-16 (Mixed 16.25 18 24.1 38.60 5 Forest) Decid &Mixed Totals 22.25 47*33.0 17-21 (Shrub-14.01 32*20.7 3.61 0 lands) TOTALS 100%(13512 ha)148 148.0 100%(2741 ha) ~*Observed greater than expected suggests positive selection. I 117 from Table 22).Doubtless the proportion of these two types that will be flooded in the vicinity of the Watana impoundment is much higher than 35%,however,this cannot be calculated because data on availability outside of the flooded area has not been calcu- lated separately for each impoundment. XI.-G.DEN AND DENNING CHARACTERISTICS-BLACK BEAR 1980/81 den sites were located and measured for 14 radio-collared black bears,2 additional approximate den locations were recorded but the actual dens were not found (Table 46).1981/82 den sites have been tentatively located from fixed-wing aircraft for 19 black bears,14 of these are from the same individuals whose dens were found the preceding year (Table 47).More precise data for these 1981/82 dens will be available in summer 1982.Locations of dens are given in Figure 8. Black bear den sites ranged in elevation from 1,300 feet to 4,340 feet,however,only one bear denned at an elevation above 3,000 feet (B304 in 1980/81).Typically black bears in the study area denned at elevations between 1,500 and 2,500 feet elevation.Of 16 den sites found in the vicinity of the proposed Devils Canyon impoundment,only one will apparently be flooded at an impound- ment elevation of 1,450 feet (Tables 46 and 47);the average elevation of these 16 dens was 2,178 feet (range=l,490-4,340 5.D.=686 feet).Of the 13 den sites found in the vicinity of the proposed Watana impoundment,9 would apparently be flooded at an impoundment elevation of 2,200 feet (Tables 46 and 47);the average elevation of these 13 dens was 2,177 feet (range=1,800- 2,750;5.D.=28l feet).Two black bears denned downstream of the Devils Canyon site in 1981 (Table 47). These data suggest that the direct impacts resulting from inun- dation of black bear dens sites will be very high for bears denning in the vicinity of the Watana impoundment and low for those denning in the vicinity of the Devils Canyon impoundment. 118 - - - - - J )~J J 1 ~j }J )~J 1 J 1 J Table 46.Characteristics of black bear dens in the Susitna study area during winter of 1980/1981. CHAMBER, Den No. Bear ID No. Age at Exit Eleva- tion Slope Aspect (feet)(Degrees)(True N)Vegetation %Canopy ENTRANCE Tree Ht.Width Coverage (cm.) (cm.) Ln. (cm.) Width'Ht. (cm.) (cm.) Total Length (cm) Previously Used? (Yes/No)A B c NATURAL CAVITIES FE~~LES w/offspring (at exit) w/2 cubs 8 B321 11 2825 42 208 Alder o 79 26 127 68 71 610 Yes 2 No w/'L cubs 19 B328 7 1950 40 218 Alder o 41 93 Yes 4 No 18'"B322'"5 13'"B304'"11 DUG DENS FE~tALES w/offsprtng (at exit) w/2 cubs 2 B301 8 ?collar shed in den 6 HALES 7 9 10 B325 B287 B324 B303 12 11 6 8 1490 1700 2240 1690 4340 1840 2065 30 46 30 50 24 53 34 178 170 88 48 52 158 191 Birch/alder/spruce Cottonwood/willow/ birch Alder Willow/alder/aspen Rock pile/tundra Alder/rock slide Alder /birch 50 50 o o o 90 49 62 38. 93 49 27 44 34 36 43 100 122 137 108 97 74 89 70 82 92 55 42 45 94 51 113 869 151 Yes Yes Yes Yes 1'" ?'" Yes 2 2 3 1 3 No No No No No Yes Yes w/3 cubs w/2 ylgs. 4 11 B289 B317 10 8 2000 2050 18 36 211 86 Alder/willow/spruce 70 Alder 0 39 27 72 41 142 93 127 93 55 78 290 128 No No 1 3 No Yes w/l ylg. w/2 ylgs. 12 21 11318 B327 6 6 2725 2000 24 35 122 379 Dwarf birch/moss/ tundra Alder/birch o 80 24 22 42 59 95 163 84 203 ~40 116 14;i 198 No 5 4 No Yes ~~LES 20'"B323'"3 1950 46 176 Alder/birch ?'"Yes SPECIES UNK.3 2340 35 (254)Dwarf birch o 50 54 170 No No '"Actual den site not found or too difficult to enter.' A Subjective characterization of quality,1 =highest and 5 B Will be flooded by Devil's Canyon? C Will be flooded by Watana Impoundment? lowest. Table 47.Distance between den sites utilized by radio-collared black bears in 1980/81 and in 1981/82.(81/82 data are preliminary as den sites have not been located on the ground as yet).- **B325 is apparently denning (in 81/82)in same den utilized by B324 (in 80/81).B324 was located near,or at,this same den (occupied by B325 since 16 Sept.)on 1 October,but subsequently moved to another den site. denned in very atypical high-elevation den in Bear ID/sex/age (1981) B287/M/ll B289/F(w/3c)/9 B301/F(w/2c)/8 B303/M/9 B304/M/ll B317/F/8 B318/F{6 B321/F/ll B323/M/3 B324/M/6 B325/F/12 B327/F/6 B329/F/1 B328/F(w/Ie)/7 B343/M/5**** B346/M/9**** B348/M/9**** B349/F/4**** B302/M/9 *B304 Distance (miles) o (same) o (same) 0.5 o (iame) 9.0 0.7 2.7 1.4 1.3** 6.8** 2.7 3.0*** 0.4 0.2 ? ? ? ? ? Approx.Den elevati{)n (1981/82) 1,700 2,000 2,450 1,690 1,850 1,950 2,000 2,200 2,000 1,500 2,240 2,750 1.900 2,100 1,300 2,350 1,600 2,550 2,100 1981/1982 den will apparently be flooded by: Devils Watana no yes no no no no no no yes yes? no no yes no Gold Creek no? Portage Ck. no yes 1980/81.- ***This bear denned with its mother (B327)in 1980/81. ****Not radio-collared in 1980. 120 -, - II).. GI-GIe 0 ..0 •II)10 CO••10.....n..e••--u-.-••... c c••GI CI Q llS..E)u II) ... CO•.. I 0 CO•.-. II) GI-'t:l ::II-II).. llS GI .D. 0.. 't:I :.0- X I ::II f1) C 't:l C ::II 0-II) C GI 't:l.. llS GI .D. .¥ U llS-.D. =llS-0 •c 0-llS U 0 -I CO GI.. ::II CD--u. 121 The distribution of known black bear den sites indicate that study-area black bears tend to den in steep terrain along the main Susitna River or·feeder streams (Fig.8).Proceeding upstream through the study area,the band of acceptable denning habitat apparently becomes progressively narrower and more con- fined to the immediate vicinity of the Susitna River,much the same pattern as seen for black bear overall distribution.This explains the greater impact of the upper impoundment relative to the lower impoundment. Of the 14 dens used in 1980/81 that have been located on the ground,8 were in natural cavities or caves and 6 were excavated. All of the natural cavity dens examined (n=6)and 1 of the dug dens examined (n=4)had apparently been previously u~ilized based on evidence found at the den site;a determination of previous use could not be made for 4 dens.Four of the dens examined in 1981 are apparently being utilized again in the winter of 1981/82 by radio-collared black bears,3 of these by the same individual that utilized the den the preceding year (Table 47).These data on reuse of den sites may indicate scarcity of acceptable denning sites in the study area or they may just indicate habituation. Of 18 den sites examined on the Kenai Peninsula,8 had been pre- viously used and 10 were newly constructed;only 1 bear reused the same den in successive years (Schwartz and Franzmann 1981). Relative to this Kenai study,reuse of den sites appears higher in the Susi tna area.All of the dens in the Kenai study were excavated (Schwartz pers.comm.)compared to 43%in the Susitna area.The average distance·between dens utilized by.the same bear (n=14)in successive years was 2.1 miles (range=0-9 miles, S.D.=2.7 miles).Comparison data for black bear dens in Prince William Sound are given in Appendix 5.Here reuse was also lower than in the Susi tna area and many bears denned in hollow trees. For 15 black bear dens visited in summer 1981,the mean slope was 36°(range=18-53°,S.D.=100).The mean slope of excavated dens 122 - - - - ..... - - ""'" "..., (x=39°,S.0.=100,n=8)was essentially equivalent to that of dens in natural cavities (x=33°,S.0.=9°,n=7).Half of the dens visi ted were wi thin 45°of True South (135-225°)(Table 46 and Figure 9). Radio-collared black bears in the study area entered dens from mid-September through mid-October and exited dens,in 1981,from early April to mid-May (Table 48).Based on earliest and latest possible den entrance and exit dates of radio-collared individ- uals,black bears spent a median period of 223 days in 1980/81 dens,61%of the year.In 1981,black bears appeared to enter dens about 2 weeks earlier than they did in 1980 (Tables 48 and 49).This may have resulted from the apparent relatively poor berry crop in 1981;fall weather conditions appeared essentially equivalent in 1980 and 1981. IX.-H.PREDATION RATES-BLACK BEAR Black bear predation on moose calves is prevalent on the Kenai Peninsula (Franzmann et a1.1980).Black bears killed 34%of 47 radio-collared moose calves,compared to 6%by wolves,6%by brown bears (low density),2%unknown predation,and 8%acciden- tal deaths or unknown causes.Of known predator-caused deaths of moose calves in this study,black bears caused 70%(op.cit.). Most black bear predation on the Kenai occurred when calves were small,less than 1 month old.High levels of black bear pre- dation of elk calves in Idaho have also been reported (Schlegel 1976). Of 23 radio-collared black bears followed-in the Kenai study,5 (22%)were known to have preyed on moose calves (Schwartz and Franzmann 1980,in press).No predation occurred in areas where moose browse rehabilitation had occurred,all predation occurred in uncrushed areas of regrowth vegetation resulting from a 1947 forest fire (op.cit.).If this same model holds in the Susitna 123 N I I I I I I I I I I I I I, I !~~~~:-"'--="'-:':-=-~-:':-=-:':-:';-::'-~-----------JB324.88· dug cavity natural·cavity Figure 9.Aspect of black bear dens In the Su-Hydro study area.1980/81. 124 Table 48.Den entrance &emergence of individual radio-collared black bears,in both 1980 and 1981. earlier 4/3-5/5 1981 entrance earlier 1981* or later than 1980 emergence 9/9-9/29 9/23-10/1 (w/3c) 9/29-10/13 9/16-9/22 (w/2c) 9/9-9/29 (w/2c)9/9-9/16 9/29-10/13 o (w/1c)9/16-9/22 Bear ID/sex B287/M B289/F B301/F B317/F B318/F B321/F B323/M B324/H B325/F B327/F B328/F B290/F B319/M B322/H B303/H B304/H B329/F B343/H B346/H B348/H B349/F B302/H * 1980 den entrance* 9/9-9/29 9/9-9/29 9/29-10/13 9/29-10/13 9/29-10/9 9/9-9/29 (w/2c) 9/9-9/29 10/1-10/9 9/29-10/13 9/9-10/13 1981 den entrance* 8/24-9/9 9/16-9/22** 9/22-10/1 10/1-10/7 9/9-9/16 9/16-9/22 9/16-9/22 9/16-9/22 9/16-10/1 9/22-10/1 9/16-9/22 9/9-9/16 9/16-9/22 9/9-9/16 9/16-9/22 ? earlier ? earlier ? ?earlier? ? earlier ? ? 5/8-5/15 5/9-5/29 5/5-5/.15 4/30-5/5 5/10-5/15 5/6-5/8 4/30-5/5 5/8-5/10 5/21-5/29 5/5-5/10 4/30-5/5 4/30-5/5 5/5-5/10 Dates indicate last observation away from den and first observation at the den, large gaps,especially in 1980,reflect flights missed due to poor flying conditions. **2 cubs lost in mid July. 125 Table 49.Comparison of radio-collared Black Bear den entrance dates.1980/81 and 1981/82.(Poor weather resulted in SOme missed and incomplete flights in 1980). J I Time Period 8/22-8/28 8/29-9/5 9/6-9/12 9/13-9/19 9/20-9/26 9/27-10/3 10/4-10/10 10/11-10/17 1980 date 8/27 -9/9 --9/29 10/9 10/13 flown 1981 date 8/24 9/1 9/9 9/16 9/22 10/1 10/7 10/16 flown Number of bears at den site/Number of bears found* 1980 0/14 ?0/14 ??6/13 8/8 14/14I-' IV 0'1 1981 0/9 0/18 1/19 5/19 15/18 19/19 19/19 19/19 *Number of bears found includes bears found and those missed during that flight that were previously and subsequently observed at the same den site.does not include those missed during that flight that were not at the den site during the previous flight. I J J .1 J .J J J J J J J I - study-area,which is comprised of vegetation in a relatively un- disturbed state,high levels of predation on moose calves by black bears would be expected. Daily monitoring of3 black bears in the Susi tna study area during the period 21 May-22 June,1981 resulted in 73 point lO-r cations (Table 29).One black bear (B342,a 5 year-old male)was observed on 1 calf moose kill and 1 adult caribou kill during this period (Table 29).This bear was also observed on a kill of an adult radio-collared moose on 22 July.No other predation was observed during the period of intensive monitoring.Regular mon- itoring of black bears resulted in no additional known kills of ungulates,although one black bear was seen on a hunter-killed moose in September (B318). We suspect that calf moose are more important spring prey than indicated by these data.Many kills were doubtless missed be- cause of relatively infrequent monitoring,difficulty of spotting ki.lls in heavy vegetation,and low numbers of intensively moni to red black bears.Importance of moose calf predation to black bear populations,as well as to moose populations,should be established by studies of radio-collared moose calves in Phase II. x.SUMMARY OF PROJECT IMPACTS. A.Brown bears. Anticipated proj ect impacts on brown bears are similar in type for both impoundments but are likely to be more severe in degree for the Watana impoundment than for the Devils Canyon impound- ment.This is because the upper impoundment is in prime brown bear habitat while the lower impoundment appears to grade into habitat which is relatively better for black bears and poorer for brown bears.In order of suspected degree of impact,the pro- 127 posed project is likely to influence brown bear populations in the following ways:- 2.Increased human presence during construction and operation of the darns will result in increased disturbance and hunting pressure which will lead to corresponding displacements and reductions of brown bear populations in the study area. Increased frequency of bears kil~ed in defense of life and property situations is also an inevitable result of an in- creased human population;this can be minimized by proper preventative regulations during construction and operation. 1. 3. Reduction in the amount of lowland habitats along the river utilized by many bears early in the spring and by a few bears throughout the year.These habitats are the first to be cleared of snow in the spring (especially on south-facing slopes)and overwintered berries as well as early spring growth are available in these habitats relatively earlier than elsewhere.Nutritionally,early spring is likely to be the most critical period for bears.Much of the area used in the early spring will be inundated by -the impoundments. Areas more distant from the impoundment shoreline may be affected by climatic changes caused by the impoundment (particularly delay of spring green-up). Inhibition or blockage of directional seasonal movements to areas of reoccurring food abundance.Routes followed in these movements will be intersected by the impoundments,by access routes,by borrow areas,and by construction and operation facilities and activities.The areas affected include caribou and moose concentration areas (especially calving areas),salmon fishing areas (especially Prairie Creek),and sites where vegetable forage is seasonally available. - - 4.Disturbance,but probably not much direct inundation,of brown bear den sites. 128 .- - 5. 6. Indirect impacts through reduction of availability of salmon in Prairie Creek and downsteam of Devils Canyon.Based on available evidence,Prairie Creek salmon runs are unlikely to be significantly affected and there is little documenta- tion,as yet,that many brown bears in the existing study area make seasonal movements downstream of Devils Canyon to fish.Brown bear populations that are resident downstream of Devils Canyon,however,are likely to be impacted by the anticipated project-related reduction or elimination of salmon spawning between Talkeetna and Devi 1s Canyon. Reduction of ungulate prey.This potential is listed last only because the importance of ungulate prey to bear popu- lations was not part of the Phase I study plan.Studies elsewhere,including the upper Susitna River,suggest that predation on moose calves by brown bear in the spring is very common.Indirect evidence suggests that brown bear predation on caribou,especially on caribou calving grounds, may al so be frequent. B.Black bears. Upper Impoundment Residents and Transients Black bears using the upper impoundment area can conveniently be broken into resident and transient subpopulation.The most affected subpopulation will be residents that have all or most of their annual home ranges upstream of the Watana Dam site,it is our suspicion that this group will be essentially eliminated by the proposed project through a combination of the following factors (listed in order of suspected degree of impact): 1.Inundation of den sites and scarcity of acceptable post- construction alternative den sites. 129 2. 3. 4. 5. Elimination of habitat through inundation.Acceptable spring,summer,and denning black bear habitats in this area appear largely limited to the impoundment area and immediate vicinity,much of these habitats will be flooded. Increased hunting and disturbance.Black bears in this area are currently very vulnerable to hunting by vi rtue of the constricted nature of their primary habitat (spruce forests along the river),this vulnerability will increase as the impoundment further constricts acceptable upstream spruce habitats.At present black bears are little hunted in this area because of its remoteness and difficulty of access i this pattern will change as project c~nstruction and oper- ation improves access and augments the human population res- ident in the area. Reduction of availability (through disturbance,habitat des- truction,and/or climatic changes)of tableland areas used for forage in late summer and early fall.The tablelands between the spruce forests along the Susitna River and the adjacent mountains north of the river appear seasonally im- portant for black bears.Access rQads,borrow areas and construction facilities which transect these tablelands are anticipated.These habitats in the vicinity of the upper impoundment are used both by bears resident in the upper impoundment area and by many transient bears that are resi- dent in the vicinity of the lower impoundment earlier in the year. Climatic changes.The nature,extent,and direction (deli- terous or beneficial)of climatic changes resulting from the impoundment are uncertain.It is considered likely,how- ever,that establishment of winter snow cover will be delayed by a warm-body effect of the mass of water behind the dam.This,in turn,may reduce the potential for berries (suspected-important food in the early spring)to 130 _R? - '""" - - - - - ..... 6. successfully overwinter because of the absence of a protec- tive snow cover in the fall and early winter (thi s appar- ently happened naturally during the winter of 1980/81 when snow cover was abnormally slight and delayed).The warm impoundment waters may also cause some early winter precipi- tation to fall as rain rather than snow and may increase the amount of precipitation because of increased local humidity. Climatic impacts from the impoundment may be more serious in the spring when breakup may be delayed because of a possible cold-body influence of the frozen impoundments.This may retard the phenology of plants important to bears as early spring forage at the most vulnerable portion of the bear's annual life cycle (immediately following den emergence). Finally,climatic changes resulting from the impoundment (temperature changes,precipitation changes,etc.)may alter the distribution or abundance of berries (suspected cri t- ically important late summer and early spring foods)or other forage plants.Vaccinium spp.production,for ex- ample,appears naturally variable from year to year and appears to correlate with bear behavior;perhaps years of low Vaccinium production correlate with winter conditions or climatic conditions during pollination (increased spring precipitation may inhibit pollination).Although the types of climatic change which may result from the proposed im- poundments are uncertain,as are the impacts of any such changes on bears,it is noteworthy that black bears in this area are on the northern limit of their natural distribution south of the Alaska Range and are,correspondingly,likely to be in a somewhat precarious balance with their environ- ment. Elimination or reduction of salmon runs downstream of the Devils Canyon impoundment may eliminate an important alter- native food source for upstream bears.This alternative may be important only during years when berry crops are sub- normal.Based on available data the number of Watana 131 7. impoundment-area residents that move downstream to fish for salmon during poor berry years may be small but has been documented (see di scussion and range maps for B348 and B343). Increased interspecific competition with brown bear in- cluding increased predation by brown bears.It is likely that the constricted distribution of black bears in the spruce forests along the river is adaptive to black bears in limi ting the degree and effectiveness of brown bear pre- dation,black bears can climb trees and brown bears cannot. If this is true,decreases in the amount of forested habitat could result in increased predation by brown bears,especi- ally in the early spring when the two species are most sympatric. - 8.Indirect impacts through reduction of ungulates,especially moose calves,that may be important prey items in early spring.This potential factor is listed last because of the lack of adequate data to reveal the level of predation that exists as well as uncertainties relative to the project IS impact on moose populations.If such predation is important to black bear populations and if moose populations are mark- edly affected,this factor may rank first or second in importance. The transient bear population,usually resident in the vicinity of the lower impoundment but moves to the upper impoundment in late summer to forage,will be affected in the upper impoundment area,by the same factors listed above in approximately the following order: 1.Reduction of availability of tableland areas used for forage in late summer and early spring (see #4 above). 2.Increased hunting and disturbance (see #3 above). 132 3.Climatic changes (see #5 above). - 4.Reduction of downstream salmon runs (see #6 above). 5.Reduction of escape habitat on late-summer foraging grounds (see #7 above). Lower Impoundment The proposed Devils Canyon impoundment will doubtless have less severe impacts on local black bear populations than the Watana impoundment but impacts wi 11 .be marked regardless.The topo- graphy of the lower impoundment area as well as the wider dis- tribution of forested habitats downstream,will result in loss of a relatively lower proportion of acceptable black bear habitat downstream.In order of suspected degree of influence the anticipated impacts of the lower impoundment are: 1.Elimination of important early spring habitats through inundation and associated impacts of climate (retardation of spring phenology)on spring forage. ""'"I 2.Reduction of the availability (through disturbance and/or climatic changes)of tableland area used by Devils Canyon-area black bears are upstream in the vicinity of Tsusena-Deadman-Watana Creeks.Impacts on these areas were discussed in points 4 and 5 above for bears resident in the upper impoundment area. 3.Increased hunting and disturbance (discussed in point 3 above). 4.Elimination or reduction of downstream salmon runs (point 6 above).This factor is of relatively greater importance to the black bears resident near the Devils Canyon impoundment 133 because of their closer proximity to these runs.In late summer 1981 three radio-collared bears resident in the Devils Canyon impoundment area moved downstream,apparently to fish for salmon. 5.Inundation of den sites. - 6.Reduction of ungulate prey.As noted above the importance of this factor is unknown which is why it is listed last. Potentially this could be the #1 or #2 impact on this subpopulation of black bears.- Downstream impacts The above predicted changes in black bea~population density in the vicinity of the proposed impoundments may affect adj acent populations as well.The most likely source of this type of im- pact would be through reduction in the number of bears dispersing from the reduced population in the study area to adjacent areas, mostly to the west.As mentioned above,some documentation of such dispersals has been obtained in this study.However,the significance of this to adjacent populations is unknown.On the short-term,activities and disturbance associated with project construction and perhaps project operation as well could force some individuals to disperse.Some of the larger movements and dispersals observed to date could,arguably,be interpreted as resulting from the increased human activity associated with Phase I activities conducted during the last 2 years,this is consi- dered unlikely however.Over the long-term,it would be more significant if the project area was a source of dispersing indiv- iduals moving to adj acent areas. Available data collected by Su-Hydro fisheries biologists indi- cate that salmon spawning in mainstem Susi tna between Talkeetna and Devils Canyon will be greatly reduced or eliminated as a result of the proposed project.If so,this would be likely to 134 - - ~- - have a major negative impact on black bear populations in this area that may depend on salmon for food.Reduction of periodic flooding of downstream riparian habitats which would result from the project may also reduce the availability of early-succes- sional stage forage which may be particularly important in the spring.These possibi Ii ties are conj ectual as downstream bear studies were not conducted in Phase I,they should be a part of any Phase I I studies. 135 - - - - Xl:.PHASE I I STUDY NEEDS AND OBJECTIVES The two-phase format of Susi tna game studies was designed to identify the kinds of impacts the project was likely to have in Phase I and,should the decision be made to proceed with a license application,information on the magnitudes as well as more precise documentation of the actual impacts would be ob- tained in Phase II.Assuming a license application is submitted to FERC,the following Phase II studies are needed to quantify the impacts of the proposed proj ect on bear populations. A.Brown -Bear - 1. 2. Continued documentation of brown bear utilization patterns of the study area with particular em- phasis on early spring utilization by many bears of areas that will be directly inundated or af- fected by the proposed impoundments.Secondary emphasis will be placed on further documentation of what proportion of the brown bear population in the study area utilize the impoundment area throughout the year.These studies will require continued radio-collaring of new individuals and replacement of radio-collars on existing study animals.As the number of radio-collared animals in the study area increases,a corresponding more preci se estimate of brown bear density in the study area will also be obtained.These studies will also hel-p clarify the relationship between the two bear species and what impacts on one species would mean to the other. Intensive studies of sites where project construction facilities are likely to conflict wi th bear use of these same areas.Preliminary analyses of these impacts based on the tentative 136 3. locations of borrow sites,access roads,and camp facilities have been discussed in this report. Transmission line impacts have not yet been addressed.Of primary importance to brown bears based on this preliminary analysis is a distur- bance of den sites caused by project access roads. Once the locations and extent of these sites have been more firmly established,more intensive studies are needed to quantify the degree of impact and to clarify procedures to minimize these impacts. Determination of essential brown bear niche- elements which will be lost or reduced by the proposed proj ect.The primary concern in these studies will be determination of the foods util- ized in the spring by many bears and throughout the year by those bears that use the impoundment- impact area and the availability of these foods relative to other areas and seasons.The tech- nique proposed to determine utilization is feces analysis,transect sampling will be used to de- termine availability.During Phase I the feas- ibili ty of the feces analysis technique was es- tablished through development of a procedure to chemically identify black and brown bear feces (Appendix 6). -, 4.Determination of the importance of moose calf and other predation to brown bear populations in the study area.Some information on the relative im- portance of moose calves in brown bear spring diets,and ungulates in general in year around diets,will be obtained from the feces analysis described in point 2,above.However,Phase I of this study,as well as previous work (Ballard,et 137 '""" - B. al.1979,Franzmann et al.1980,Gasaway et al. 1977,and Schlegel 1976)have clearly demonstrated that predation-rate information gathered by ob- servations of radio-collared predators underesti- mates the importance of this predation to popu- lations of both predators and prey.Relative to other areas of Alaska where predator-prey rela- tionships have been studied,the Watana area is unique because of the presence of 3 major preda- tors (brown bear,black bear and wolves)and 2 major ungulate prey (moose and caribou).For this reason,it would not be-reasonable to extrapolate resul ts from other areas to the proj ect study- area.Anyone of these 5 species could be mark- edly impacted by proj ect impacts on the other (except caribou-black bear.relationships are un- likely to be significant).An accurate appraisal of overall project impacts must consider species interactions,not just individual species by them- selves.In addition to direct impacts on preda- tors.,the proposed proj ect has potentially large impacts on both ungulate species which,if such impacts should develop,would in turn likely have significant indirect impacts on all 3 species of predators ~.These predator-prey relationships should be studied in cooperation with ongoing Phase I I ungulate investigations. Black Bear 1.Continued documentation of black bear utilization patterns in the vicinity of the proposed impound- ments in order to quantify losses to black bear habitats and populations.Continued emphasis will be placed on direct losses to black bear denning habitats.The possibility that reductions in 138 brown bear density as a result of project impacts could-benefit black bear populations may also be clarified by these studies.These studies will require the continued radio-collaring of new in- dividuals and replacement of radio-collars on existing study animals.As the number of radio- collared animals in the study area increases,a corresponding more precise estimate of black bear .... , density in the study area will be possible.More precise estimates of density should also be ob- tained through August when·black ~aerial surveys in bears are concentrated on relatively open habi tats. 2.Intensive studies of sites where project construc- tion facilities,borrow areas,access roads,and transmission lines will conflict with bear use of this report.Important impacts on black bears are expected to result from di splacement from berry- rich habitats used by black bears in late summer as a result of borrow areas and camp faci li ties. Access roads and transmission line corridors are - expected to impact black bear populations also,~ especially through disturbance of den sites and improved access to the general public.Once the locations and.extent of these sites have been established,more intensive studies are needed to quantify the degree of impact that can be expected and to clarify the procedures that can be imple- mented to minimize these impacts. 3.Determination of essential black bear niche- elements which will be lost or reduced by the 139 4. proposed impoundments.As di scussed for brown bear,above,these studies will concentrate on food habits and food availability.Fecal analysis techniques will be utilized.Black bear pre- dation-rates on ungulates will also be studied as outlined for brown bears above. Downstream black bear studies.During Phase I studies the potential for significant impacts on bear populations downstream of the proposed im- poundments were not fully appreciated.Results of Phase I work,however,clearly identify the poten- tial for substantial downstream impacts on bear populations through two mechani sms: .... a.Indirect impacts through reduction or elimin- ation of mainstem Susi tna River and associ- ated slough spawning of salmon.The results of Su-Hydro fisheries studies clearly demon- strate the likelihood that the proposed down- stream flow regimen will reduce or eliminate salmon spawning in upstream portions of the main Susitna River and adjoining sloughs and tributaries.This effect would be most marked in that section of the river upstream of Curry to Devils Canyon (T.Trent,C. Estes,W.Trihey,'pers.comm.on 18 Nov. 1981).The impact this would have on the bear population is unclear.Su-Hydro fisher- ies biologists report that bears of both species,but particularly black bears,ap- peared to be especially prevalent along this section of.the river when salmon were spawn- ing (late August-through September)in 1981 (B.Barrett and K.Delany,pers.comm.). They reported that of 15 radio-transmittered 140 ............"-----_._-----~.._--~--_._-- b. salmon,2 (27%)were taken by bears,overall they estimate that 4%of their marked salmon were taken by bears.Their observations suggest that bears repeatedly used the same preferred fishing sites on islands and gravel bars to fish and to scavenge for salmon car- casses.They also noted well-developed bear trails paralleling the river.Highbush cran- berry as well as salmon were common in bear feces found along the river by these re- searchers.These observations coincide with movements 3 radio-collared black bears that moved in downstream August from the impound- ment area,evidently to take advantage of this salmon resource.One subadult brown bear made a similar movement in May but this was considered a probable natural dispersal. 'Perhaps such movements of upstream black bears are particularly important during years,like 1981,when upstream berry crops are subnormal.Local residents of the Tal- keetna area are well aware of the seasonal concentration of bears along the river during salmon spawning and frequently hunt bears at this time from riverboats. This apparent concentration of bears along the river and their apparent reliance on a salmon resource which is threatened by the proposed impoundments makes an expansion of the bear studies to include this area essen- tial in Phase II of Su-Hydro impact studies. Indirect impacts on downstream bear popula- tions through alteration of periodic flooding patterns and corresponding vegetation changes 141 ~, - -- should also be investigated during downstream Phase 11 bear work.This kind of impact is equivalent to that being investigated for moose populations in Phase I of this study. Like moose,both species of bear may be espe- cially dependent on early-successional stage vegetation that results from periodic flood- ing of downstream habitats (Singer 1978); this dependence,if it exists,would likely -be more prevalent in the early spring because these riparian habi tats are the most pheno- logically advanced in the spring.Adequate spring foraging is particularly important for bears,which have spent the preceding 6 months fasting in their winter dens.The Su-Hydro fisheries study team did not report noticing concentrations of bears along the river in the early spring,but such foraging might easily have gone unnoticed. 142 XII.REFERENCES *Baker,A.B.1972.Further notes American black bear in captivi ty. 59(10):1-4. on the breeding of the Smithsonian Misc.Co11. *Ba11ard,W.B.,A.W.Franzmann,K.P.Taylor,T.Spraker, C. 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Department of the Environment,Fisheries and Marine Service. Ottawa.382pp. *Rockwell,S.K.,J.L.Perry,M.Haroldson and C.Jonke!.1978. Vegetation studies of disturbed grizzly bear habitat.Third Ann.Rep.Border Grizzly Project,C.Jonkel,ed.Univ.of Montana,School of Forestry,Missoula.256pp. Rogers,L.L. population Minnesota. Minneapolis. 1977.Social relationships,movements,and dynamics of black bears in northeastern Ph.D.Dissertation,Univ.Minnesota, 194pp. 149 Schlegel,M.W.1976.Factors affecting calf elk survival in northcentral Idaho:a progress report.Annu.Conf.West. Assoc.State Game and Fish Comm.56:342-355. *Schwartz,C.C.and predation on moose. progress report on 17.3R.81pp. a.W.Franzmann. Federal Aid in projects W-17-11 1980.Black bear Wildlife Restoration and W-21-1,Job No *Schwartz,C.C.and A.W.Franzmann.1981. predation on moose.Federal Aid in wildlife progress report on projects W-17-2,Job No.17.3R. Black bear Restoration 43pp. *Schwartz,C.C.and A.W.Franzmann.in press.Effects of habitat manipulation on black bear predation of moose calves.Paper presented at 6th IntI.Conf.on Bears,Their Biology and Management,Feb.,1980.Draft in Appendix I I of Schwartz and Franzmann 1980. *Singer,F.J.1978.Seasonal concentrations of grizzly bears, north fork of the Flathead River,Montana.Canadian Field-Naturalist 92(3):283-286. Spencer,D.L.and R.J.Hensel.1980.An assessment of environmental effects of construction and operation of the Terror Lake hydroelectric facility,Kodiak,Alaska.Brown bear studies and Mountain Goat Studies.Prepared by Arctic Environmental Information and Data Center,U.of Alaska. 100pp.(mimeo). E.,Jr.1955.The black bear and its status in Game Div.Bull.4,Maine Dept.Inland Fisheries and 55pp. *Spencer,H. Maine. Game. 150 *Spraker,T.H.,W.B.Ballard,and S.D.Miller.1981.Brown bear studies,Game Management Unit 13.Alaska Dept.Fish and Game,Final P-R Proj.Rep.W-17-10 and W-17-11, Job.4.13R (In Press).- *Stoneberg,R.P.,and C.J.Jonkel.1966. black bear by cementum layers. 30(2):411-414. Age determination of J.Wi ldl .Manage. *Tait,D.E.N.1980.Abandonment as a reproductive tactic-the example of grizzly bears.Amer.Nat.115 (6):800-808. *Tisch,E.L.1961.Seasonal food habits of the black bear in the Whitefish Range of northwestern Montana.MS Thesis, Montana State Univ.,Missoula.108pp. *Troyer,W.A.,and R.J.Hensel.1964.Structure and r'" distri~ution of a Kodiak bear population.J.Wildl.Manage. 28:769-772. *Ci ted in thi s report . .- 151 - """ APPENDIX 1.BROWN BEAR DISTRIBUTION MAPS 152 ,..,. 153 --II).. ID-ID E o 10 N CD H E Co)- ID III Co)..s. -co 0)- I oco 0)- •ID ell C III.. IDeo.... III ID ,g c:: ~ o.. ,g =III-o ID-•oc. Eo (,) .o- e,. + ~ ~ A January -,",une,1980 +July -December,1980 X January -June,1981 <!>Ju'y-December,1981 sca'e:1 em ..0250 meters y * I-' 11l >l:>o Figure 11.Locations of all unmarked brown bears observed during radio-tracking efforts,1980 -1981. J _oJ ....oJ .J ......1 J .I I J J !I J I J 1 J J J 1 1 I 1 )1 1 --I -1' JED.n 81h.1980 A January -June.1980 +July -December.1980 X January -June.1981 ~July -December.1981 Bcale:1 cm=6260 met.r. r l-' U1 U1 Figure 12.·All point locatlona and complete known home range for brown bear 214. (Include.locatlona only through 9/1181) I-' U1m *Den alte,1980 A January -June,1 S80 +July -December,1980 X January -June,1981 ~July ~December,1881 8cale:1 c'm-8250 metera Figure 13.All point location.and complete known home range for brown bear 277. (include.location a onl,through 9/1/81) ]]J I _.J .....,,1 I J •I J I I 1 J I J ]1 ])1 ]J ] 1-', In -...J •Den alte.1980 A January -June,1980 +July -December,1980 X January -.June,1981 <t>July -December.1981 8cal.:1 em ...6250 met.r. Figure 14.All point locallon.and complet.known home range for brown bear 280. (~nclude.locall~n.only through IiI/1I81) / *Den alte.1880 4 January -June.1980 +July -December.1880 X January -June.1981 <!>July "-December.1981 scale:1 em'"8250 ~ .----;-.......-- t:: 00 Figure 16.All point locatlona and complete known home range for brown bear 281. (Include.location a only through 9/1181) J -1 J l J J J I I }J -1 .)J 1 I ]], J 1 -1 I-' lJ1 1.0 ~ IE Den alte.1980 A January -Jun.e.1980 +JUly -December.1980 X January -June.1981 ~July -December.1981 8cale:1 em-8250 meters I''~~\ figure 18.All point'locations and complete know"!home range for brown bear 283. (include.location.only through 8/1/81) ~ +~ ~ *Den alte,1880 A January -June,1880 +July -December,1880 X January -June.1981 ~July -December,1881 Icale:1 em-8250 meters ./1 / I--' 0'\o Figure 17.All point locatlona and complete known home range for brown bear 293. (lnclud ••locatlona only through 9/1/8 H J I .!I I .'J I J .;1 I I ]---]J I ])1 1 1 J 1 j 1 J j I-' 0'1 I-'A JE Den .I~e.19ao A Jan~ary -June,19aO +JUly -Decel1'lbe.,1880 X January -June,19a1 ~July -December.1881 sca'e:1 cm-8250 meter. Figure 18.All point •aca t ions and c omplet e know n h om-.range for brow n bear 294. Un~ludes locations only through 9/1181) ~ JE Den .....1880 A January -June,1980 +July -D.•c.,nb.r.1880 X January -June,19111. ~July -Dec.mbar.1881 8<:ala:1 em ..8250 meter • ...... 0'1 '" Figure 19.All point locations and complete known home range for brown bear 299. (Includes location.only through 8/1/81) J I ••J .1 J J J I .J J J J J ].1 J )1 J -]-j ]]j i 1 ] ~pen aUe.1880 A January -June.1980 +July -December.1810 X January -June.1981 ~July -December .1911 ac a Ie:1 em.6250 met era I.J I-' 0"1 W Figure 20.All point locations and complete known home range for brown bear 308b. (Includes location a only through 8/1181) .IE Den aite.1880 •January -Jun ••1880 +July -Deaambar.1880 )(January -JURe.1881 ~July -OaC8 ...1I.,.18i 1 acala:1 c ....8250 metera r I--' 0'1 .J::>, figure 21.~II point locatlona and comp.lete known home range for brown bear 312. (includes ·Iocatlons only through 8/1181) J )J I ,J J ))I I J 1 j J J I 1 J 1 )j J )1 J I )IE Den lite,1880 A JanulUY -June,1880 +July -December,1880 )<January -Jun",1881 <!>July -December,1981 acale:1 em-6250 metera If 1-'- 0'\ U1 Figure 22.All point locatlona and complete known home range for brown bear 313. (Includes locations only through 8/1/81) .......m 0"\ .,.D...aU ••1880 .4 ".nua ..y -June.1880 +.lull -O.c.mb ....1Q80 )(January -June.1881 ~July -D.c.mb ....18el acale:1 em-8250 mel·.r. v r---.. Figure 23.All point location a and campi ...known hom.rang.for brown bear 331. (Include.locations only through 8/1/81) J J I J J )J •»I J ,)j .1 •j 1 J I J 1 1 ]I I 1 ]]J ))1 j if Den elte.1880 A January -June.1880 +July'-Oeee.-ber.18aO X January -June.1081 ~JUly -December.1881 aC8le:1 em-8250 I-' 0"\ -J Figure 24.All point locatlona and complete known home range for br9wn baar 334. (lnclud 88 loca tlon a onl y through 8/1/81) .l /-~,/~ JE nen alte,1880 A January -June,1 ••0 +July -December,11.0 X January -June,1111 ~JUly -necember.1881 acale:1 em-8250 metar. I-' 0'1 CD Flgur.26.All point location.and complete known home range for brown bear 336. (Includes locations only through 8/1/81) J J t J .J I J J ..J I J I .J I ).]J ]J J ))1 J j 1 1 lIE Den .lte,1980 A January -June,1980 +July -December,1980 X January'-June,1981 ~July -D'E/cember,1981 8cale:1 cm m 6250 meters ~ ~ .~ I-' 0'1 1.0 Figure 26.All point locations and complete known home range for brown bear 337. (includes locations only through 9/1181) ( /' r---...J' ...--- / ~ •Den lite.1880 A January -June.1880 +July -December.1980 X January -Jun ••1881 ~July -O.c ....b.r.1881 scale:1 cm-6250 meter. /" I-' -....Jo Figure 27.All point locatlona and complete known home range for brown bear 340. (Includes locatlonl only through 9/1/81) J J J ,J )J ,I ~m !.1 i J I ]j 1 1 i J J I ( )IE Den lite.1880 A J.nuary -June~1880 +July -~·.c.lRber.1880 X January -June.1881 <!>July -December.1881 scale:1 em-82150 meters /J I-' -.-J I-' Figure 28.All point locatlona and comple"·known home range for brown bear 341. (Includes locatlona only through 9/1/81) r-' -....J I\) •Den elte,1980 A January -June,1880 +July -Dece.b.r,HI80 X January -June,1881 ~July -December,1881 acale:1 em-7260 met.,. f Figure 29.All point locations and complete known home range for brown bear 342a. (Include.locations only through 9/1/80 m )1 .~J !J J j )I J .1 ,cJ, J J J J 1 I J "I J 1 J 1 » ...... -...)w ~Den lilte.1880 ~January -June.1880 +July"December.1880 X January -June.1881 ~J~ly "':'December.1881 scale:1 em""8260 mete,• Figure 30.All point locations and complete known home range for brown bear 344. (Includes locations only through 8/1/81) .-' ,.,.. APPENDIX 2.BLACK BEAR DISTRIBUTION MAPS 174 \- """I 175 -CD ~ G).. G) e o 10 CD 10 IIe u .... G) III U•- .... CD at.... I o CD at.... CD G) CD C III ~ G) eo ~ =ou· Io 'a II ~ =II-o G).. •o Q,e o () I-' -.,J 0) ~January -June.1980 +Jul,-Oece",b.r.1880 X Januar,...June.1881 ~.lui,-O.cembn•.1881 aoal.:1 em ..5850 -me ••,. ~ Figure 32.Locatlona of all unmarked black beara obaerved during radio-tracking effor'a.1980 ...1981. ,t I ),I ~I .B I I ) JE Den alta.188'0 <!)Den alte.1881 A January -June,1980 +July -December,1980 X January -June.1981 ~July -December.1981 Beale:1 em.&8&0 mete,. I-' -,.J 00 Figure 34.All point locatlona and complete known home range for black bear 288. J ~J J t j I ,I ,I ))I I J ) ]j ]1 1 1 1 ,l 1 l--' -...J \.0 •Den alte,1880 (!)Oen.e ..e,1881 A January -June,1980 +July -December,1980 X'January -June,1981 ¢>July -Oecemb.."1981 Icale:1 em.5850 mete,e ~. Figure 36.All.point locations and complete known home range for black bear 289. .......coo Figure 38.All poln'location a al':ld compl ••e ~nGlwn home nnge fOr black bear 280. ¥Den a"e.1180 (!)De ..a"'e.1881 AI.January -June.1980 +July -December.1980 X January -June.1881 ~July -Decemb.,.1881 acale:1 em.5850 meter. J J J •j J I ;.I - 'PO ~0 (f) -~•CD Q .II: U• Q.. 0-•CI "'""C•~ CD E 01:,- c•0 .~ C .II: •-G) ""'"Q, E 0 u ~,wIiS. c• I)1 .. 0 .....c 0 CIQ 'PO CIQ G)0j-CD CD CD CD __ •-CD 'P'CD ...•i •-.-.e·u.....0•.CD 0•CD ~0 -C 4 C .a 10 -.,lICl ::I E :I E 10 C0CD,CD -,CD II)0......U u n Q,.CD .--.e-CD •>-Cl ->0-Cl u =--....<••_.r •-::I->-::I >-.C C C -C CD CDCD••:I •:I (f) Cl Cl ,.,,,CD CD )IE E:J <EI+X ~0 ~•::I CI u.182 1 )J 1 )J ).-J ~l lE D~n eUe,1180 (!)Den eUe,1181 A January _.June,1980BIII....July -December,1980 X J,nuary -June,1881 ~July -December,1981 ecale:1 cm.&880 meters Flgur.39.All point locations and complete known home range for blap,k be.r 302. ..... - - - •uo c •ell C•.. ~o- -- •Eo ~ c•o C .Ie •-•-Go Eo g ~ C \\I •co-- -c.-o Go .o...•• ~. :II ell I&. ..••.a.. u•-.a po •0 ~ 0 CI po CI •-CD C»CI C»-at po C».po •po po .-E. ~.~.•0••0 po •.a II) CD CD c .a c CD:I E :I ECD.at .,•.,•II)po ...u u •..••E••=--Q =--Q g----~~I•••I •:I =--:II =--C C C -C -•••:I •:IIQQ.,.,.,., ~)I e "E1 +X~ 184 1 -J 1 }1 1 1 J J ] I-'., 00 U1 *Den lite.1880 (!)Den lite.1881 A January -June.1880 +July -December.1880 X January -June •.1881 ~July -December.1081 Icale:1 em.alSOmttler. Figure 41.All point locations and complete known home range for black bear 304. •Oen.lte,1880 (!)Den .lte,1881 A .Januar,-June,1880 ~~I +Jul,-December,1880 X Januar,-June,1881 <!>July -Oeeembe;,1881 aeale:1 em-6810 ....t.r. Figure 42.All point locations and compl.te known home rlnge for black bear 306. J )J I I I 1 I }J •J "J 1 )J 1 ;. ;K 0 en alt e.1 980 (!),Den alte.1881' A JanLiary -June.1980 +Jul'y'-Oeeember.1980 X January -'June.1881 ~JuIY -December 1881 aeale:1 em-5850 mete,. ...... 00 -J Figure 43.AI~point locatiOna and complete known home un.e tor black be.,'317. .......coco *Den alte,1980 (!)Den al.te,1981 A January -June,1'10 +July -December.1880 X January -June,1981 <!>July -December,1981 .cale:1 cm:r.8850 ."ete,. Figure 44.All pol'nt locatlona and complete known home range 'or black bear 318. L~I ,.~~~1 J I J J ,.I J I 1 J J ]~l 1 ~1 1 -)~~J j JE Den alte.1980 (!)Den aUe.1981 It.January -June.1980 ffi r I (\)J ~II +July -December.1880 X January -June.1881 ~JUly -December.1981 aca'e:1 cm=5850 mete,. Flgllre 45.All point location a and complete known home range 'or black be.,$19. j. I I-' ~o •D.n an •.1180 (!)Den elte.1181 A January -June.1880 +July -December.1880 X January -June.1881 <)July-December.1881 ~cale:1 em-8850 mete,. Figure 46.AU point locations and complete known home range for black bear 32'1.- t J J J I ]J I I I;':IV 1 ]J I 1 J ~-B 1 -j )]-~l 'I J i ;tE D'en alte.1880 (!)Den alte.1881 A January -June,1980 ~I'll +July -December,1880 X January -'June.1881 '¢>Jpl,-D'ecember 1881 acale:1 cm-5850 meter a Figure 47.All point location a and complete known home range for black be ar 322. - 0 .-"..0 CD 0-CD •CD CD to Q)-c ...CD ..Gl.-..-.E......••CD CD 00...C .D C ..D II) CD CD :::I E :::I E CD Q)GIl ..,•..,CD II)...t-O 0 II..I CJ CJ E••~Q >-c u--....--I••••~~~>-c c·c -c:-•••:::I •:::IClIQ......,., )E €I <f3+X~ . t') w t').. "•.a.. u "-4,.. 0.. •0c•.. •e 0 ~ c•0c ""•-•-Q, E 0 U 'U C ""c 0--•u 0-c-0 Q,--C. CD..•.. -~ 0-~ 192 - - - - -s J )I 1 ))J } ....... \.0 W Figure 49.All point locations and complete known home ,ange for black bear 924. •Den alte,1980 (!)Den alte,1981 A January -June,1980 +July -December,1880 X January -June,1981 ~July -December.1981 acale:1 cm:5850 metera c .. C tD ..II» tD at •CD .0'..0 .........~.~ c ..•••• tD •C Il C Il •CD ~E ~E.......,•..,• I 0 I 0.••••Q Q......>->---..~•••I • C C ~>-~>-••c -c - I:l .Q •2 •~...,.,..,.,.e ~+X(> 194 •..•-•E c II).. CD II)•E u.. ••0• . to (\I (II) ..o-.. CI C•.. •Eo ~ c l'o C .¥ •-•-Q, Eo U 't:I C co •c o-...•u o...c '0 Q,-- . C to •.. ::I Q-"" ..... c tI CI C \Ill ~ = .. \Ill•.&:II .:Jt:o \Ill .&:II -c oa. ... lD •~ :. CI ~ tI Eo .c c t-o c: .:Jt: •..•-Co Eoo "CI C \Ill \Ill Co..•uo ..o- - ~ •0 ....~fi~ ·0 G:)...10 •III III ..Cl ••O·...at ... "E..........,....~-0..••~ O'...•I:l •.&:II ID CD .,c E c E CD,~:.lDaIII.,tI .,•......0 0 •..tI •E.-.•tI >-Q >-Q 0.... ~~---,.•,...\Ill \Ill •~>-~>-c:c:c:-c -•tI ••':.•:I -Q C .,.,.,.,• ()0)I.E)<CJ +X • 195 J ]]1 1 )·--~1 )1 J *Den alte.1880 (!)Den elte.1881 I-'rII A January -June.1180~+July -December.1880 X January -June.1111 ~July -December.1881 acal.:1 em-SISO metera figure 63.All point locatlone and complete known home "range for black bear 328. ,1E Den IUe.1980 (!)Den aUe.1981 111 A January -June.1980~II +Jut'y -December.1880 X i.rluary -'June.1881· <!>July -December 1881 aca_e:1 em-58io mete,. Figure 54.All point locallons and complete known home .range 'or black bear 330. .:- J )J J I J )J .J J •J J _J ,~ 0 p.•~ 0 ID p ••ID CD •CIt -CD p CIt .p •p p E...~.~ 0 p ••••0 •ID 1:..til C .til lD CIt CIt ~e :I E • p p ..,•..,•lD U a •..••E••Q Q--..=--u-~,..••••, p I:C :::I »-~>-I:I:·.••- -• Q Q •~•:::I -.,.,..,.,• *E).,+X~g• 199 ..••J:I .lI.o•-.til..o-•CIt I:•~ •Eo ~ I:•o I: .lI. •-• Q, Eo g 'V C••I:o--•g o-c o Q,_.-c. 10 10•.. ~ CI-... r ./ ...... *Den alte,1880 (!)Den alte.1981 A Januar t -June,1810 +July -December,1880 X January -June,1881 ~July -December,1981 acale:1 em ..3700 me'er • .. tv.:>o Figure 66.All point locations and complete known home range for black be.r 343. J!~.J ,;~J I j !J ,...1 ....J 1 "..., .c•to).. III•.a ~ u III .a.. 0-•tlI C III.. •E 0 s: c I: o.,~ c ~ • II 0.' E 0 U '1:'c III f) f)c0..-..00lID..-CO,•-CD Gl CO CD ,-•~....~.-•0..........E 0....,..••••0 --0 ....c .a c .a to cCDto::l E ::l E CDatat.,.•.,•to 0........0 u II 0...I ••E =• • »a »C u <--....-I'.f)••I .....:t '»:t »....c c c -c .-•to•••..:t III :t -.-c c .,.,.,.,III "U ..)IE E)~+X~•:t Q-LI.. 201 tv::> tv )IE Den a"e.1880 (!)Den .ite.1881 A January -Jun ••1980 +July -December,1980 X January -June.1981 ~July -December.1881. Icale:1 em ..3700 me'er$ \. Figure 68._All point locations and comple'e known home range for black bear 348. J ••J - _c J J J J I ))J J J .1 ]I ."'""CD ~ t')..••,Q JC U•~~ ,Q.. 0-•t:Ic:•.. •E 0 .I: c: ,~•0c: JC •~~..•-Do E 0 U!~ ~c:••0 .....•~0 •...CD •c: CD ClD «I "..0 ClD ...CD ...•.- E ...........•.....0 u.•••00...•.0 .a IG CD CD c:c:E CD••:lI E :lI lD .....•..,•c:.......U ·u •0I...••e Do~••..CI >-CI u......=-..I I••••...C:lI >-:lI >-c:c:c:c:••••:lI •::I CD ~CI CI ..,~..,..,ell It) ~E)~+x $u ••.. :lI \..,t:I &I.203 XI I I.APPENDIX 3 DENSITY AND BIOMASS ESTIMATES FOR AN INTERIOR ALASKAN BROWN BEAR POPULATION Sterling Miller 1 and Warren B.Ballard2 lAlaska Dept.of Fish and Game,333 "Raspberry Rd.,Anchorage,AK 99502 2Alaska Dept.of Fish and Game,P.O.Box 47,Glennallen,AK 99588 Miller,Sterling and Warren B.Ballard.1982.Density and bio- mass estimates-of an interior Alaskan brown bear population. Canadian Field-Naturalist 97 (): Abstract:Intensive capture efforts for an interior Brown Bear (Ursus arctos)population in southcentral Alaska permitted cal- culation of a minimum density estimate of 1 bear/6lkm2 based on the total number of captured and observed bears.Petersen tech- nique (mark-recapture)estimates on the same data,corrected for biases,yielded an estimate considered more accurate of 1 .bear/41 km2 .Females with newborn cubs were identified as having lower probabilities of capture than other bears.Brown bear bio- mass in the study area was estimated at 262 kg/100 km2 . Keywords:Brown Bear,Grizzly Bear,Ursus arctos,density,bio- mass,Petersen technique. 204 Accurate bear density estimates have been difficult for wildlife managers and researchers to obtain.Direct counts are seldom possible because of low observabili ty and generally low den~ si ties;indirect estimates based on scats or tracks are seldom attempted because of the infrequent and highly variable distri~ bution of these signs in both time and space.Reliable density estimates have been derived primarily from intensive marking and radio-tracking studies wherein essentially all bears in a well- defined area have been captured and monitored over a period of years.Except for such studies,most reported bear densities represent little more than a guess on a number of bears divided by the area of some unit of management significance.Al though such estimates have value in some circumstances,lack of definite procedures make replicate studies difficult and density compari- sons between areas questionable. The purpose of this paper is to report a Brown Bear density esti- mate in a portion of interior Alaska where no previous density estimates have been made.The opportunity to investigate Brown Bear population densities in this region arose as a result of an effort by the Alaska Department of Fish and Game (ADF&G)to experimentally reduce Brown Bear numbers,by transplant,in order to evaluate the response of Moose (Alces alces)calves to relief from Brown Bear predation (Ballard et al.1980).These studies were conducted in an area where Brown Bear home ranges and move- ments had been previously documented (Ballard et al.in press). The design of these studies permitted a bear density estimate through use of a standard population estimation technique (the Petersen estimate). Potential sources of bias and assumptions implicit in Petersen estimates have been widely reported (e.g.Seber 1973).Although all of the potential sources of bias could not be adequately tested or adjusted,we feel that the procedures reported in this study provide a bear density estimate that is based on objective 205 ~I - - .,.,. - numerical procedures,is replicable in other areas or at other times to provide directly cdmparable estimates,and,at least in relatively open areas with moderate to high bear densities,may prove to be quicker and less expensive than intensive,long-term, radio-tracking studies designed to provide density estimates.We further believe that the density estimate that resulted from these studies is realistic. STUDY AREA AND METHODS The bear removal area encompassed 3,436 km 2 centered on the headwaters of the Susi tna River in southcentral Alaska.The study area was bordered on the north by the Alaska Range,on the :-east by the Clearwater Mountains and on the southwest by the Talkeetna Mountains.Between these mountains is a broad,flat plateau known as Monahan Flats (823 meters elevation)crossed in several places by the braided glacial tributaries of the upper Susi tna River. The vegetation in the.study area was predominently shrubs com- posed of dwarf birch (Betula nana)and willow (Salix spp.). Local areas of spruce (Picea glauca and P.mariana)are found along river courses and areas of poor drainage.Vegetation at higher elevations is open tussock grasslands . .... - Bears were located by 2 fixed-wing aircraft (Piper Super Cub PA-18)each with a pilot and observer.Once located,bears were darted from a helicopter (Bel.l 206B)and removed from the area as described by Miller and Ballard (in press).Fates of transplant- ed bears were described elsewhere (op.cit.). Ages of adult bears were based on sections of the first premolar similar to the methods described by Mundy and Fuller (1964);ages of cubs and yearlings were based on size and tooth replacement. Ages of the spring-captured bears were standardized as years plus 206 (0.5).Weights were obtained using a hand-held spring scale with a capacity of 91 kg or a spring scale with a capacity of 680 kg mounted on a boom affixed to the front of a pickup truck. Forty-seven bears were captured from 22 May to 7 June 1979. Additional efforts on 21-22 June resulted in the capture of one addi tiona1 bear and the recapture of one returning bear.All observed bears were captured,except for OIJ.e unmarked individual. Search efforts were not uniform throughout the experimental area, but rather were concentrated in its central portion.Some bears were located at moose kill sites,including kills of radio- collared moose calves equipped with mortality-sensor radio collars (Ballard et a1.1980).Of the bears captured the pre- ceding year (1978),only two retained functioning radio collars; both of these animals were radio-tracked and recaptured on the first day of the removal effort. Twelve Brown Bears marked in 1978 were in the experimental area, these served as the basis for adjusted Petersen estimates of population size.In this estimate it was assumed that all 12 of the marked bears were still alive and present in the experimental area in 1979.Mark-recapture calculations were made separately for each sex and included all bears older than 3 y in 1979.This age restriction was utilized because no yearlings were marked in 1978,so no marked 2.5 y-old bears could have been present in 1979.The probability of capture of 2.5 y-old bears in 1978 was assumed equivalent to that of 3.5 y-old bears in 1979,therefore no need to correct for recruitment into the 1979 sample of bears 3.0 Y or older was necessary. The Chi square test statistic was utilized to compare subpopu1a- tions on the basis of sex ratio.The equation utilized in Peter- sen estimate calculations was (Ricker 1975): N =(00+1 )(C+1) (R+1) 207 - - .- In this equation:M =number marked in 1978,C =number captured in 1979 andR =number of recaptured bears in 1979. RESULTS AND DISCUSSION The number of captures/day ranged from 0 to 8 (0-4 for adult bears).Daily capture rates for the 17-day continuous removal effort were highest in the first 6 days (4.5 bears/day),lowest in the middle 5 days (0.8 bears/day),and intermediate in the last 6 days (2.7 bears/day).This pattern of capture probably resulted from normal seasonal movements of Brown Bears from high elevation den sites on the periphery of the study area to the flat central portion where search efforts were concentrated. The possibility that this pattern of capture resulted from immi- gration into the study area was rejected on the basis of analyses of sex and age composition as related to time or location of capture.For this purpose a periphery zone was defined as the area wi thin one average home range radius inside of the search area,15.7 kIn for males and 11.5 kIn for females (Miller and Ballard in press). Sex ratios of captured bears were not significantly different in any of three different groupings of consecutive time periods (six 3-day intervals,three 6-day intervals,and two 9-day intervals) (P©0.30).The sex ratio in the center of the area throughout the capture period was skewed in favor of males (8:7);this was not significantly different from.the sex ratio in peripheral areas during the last half of the removal period (3:2 in favor of males)(P©0.2). A similar lack of evidence for immigration existed in age ratio data.The seven males captured in the last half of the capture period were younger (x=5.8 y)than the 12 males captured in the 11t='..L first half (x=7.6 y),however,excluding one exceptionally old 1#91 208 bear (21.5 y)no differences in male ages were apparent (5.8 y and 6.2 y,respectively).No differences were apparent in the average ~ge of eight females captured early (x=7.1 y)relative to seven captured later (x=7.6 y). These analyses provide no reason to rej ect the assumption that the bear population in the study area was "closed"(Seber 1973) with respect to immigration or emigration.Rigorous examination of this assumption would be less necessary under experimental designs where captured bears were not being removed from the population. Minimum Population Estimate The number of bears actually captured was 48.In addition,eight bears were known to have been missed in the removal effort (2 of unknown sex which were observed in June and July,2 others obser- ved in August,and 4 from 1978 which were not recaptured in 1979, 2 males and 2 females).These bears were individually identified on the basis of pelage,size and the absence of ear flags or other marks.Therefore,the study area population contained a minimum of 56 bears.This number appeared to be a reasonable minimum estimate as some bears which were missed in the capture effort were doubtless also missed during subsequent monitoring flights.Furthermore,the rate at which bears were being cap- tured in the last days of the removal effort clearly indicated that not all bears had been captured. Mark-Recapture Population.Estimates Seven male bears were captured and marked in the study area in spring 1978 (Ballard et al.in press).Of these,all were recap- tured in spring 1979 except for two,both 3.5 y in 1978.Both of these bears were doubtless in the study area in 1979,as each was verified in or near the experimental area in 1980.One of these bears had a functioning radio collar in 1978 and was relocated 15 209 - - _._-,.-_..__.-_.__.._._----...,-"--..----....._---------~-------._--_......_._-_.__.__.. times in the center of the removal area that year.On this basis it was concluded that both of the previously marked males not found in 1979 were present.One of the 1978 captured males still had a functioning radio collar in 1979.This bear was,corres- pondingly,easily tracked and captured in 1979 and therefore was excluded from Petersen estimate calculations. r r- I I Five female bears were captured and marked in the study area in spring 1978 (Ballard et ale in press).Three of these were re- captured in spring 1979.One of the recaptured females still had a functioning radio collar and was,correspondingly,excluded from Petersen estimate calculations as trap-prone.The two fe- males not recaptured in 1979 were 10.5 and 4.5 y-old in 19,78, both were in estrus when captured in 1978 and therefore likely had newborn cubs in 1979.The older bear was observed mating in 1978,and the younger bear was observed in the company of another,presumably male,bear in 1978.Both of these females had functioning radio collars in 1978 and were well-documented experimental area residents.Both females were assumed present during the 1979 intensive capture effort. Excluding the trap-prone bears described above,adjusted ,mark- recapture calculations (Ricker 1975)were made for each sex using the total number of bears 3.0 years or older captured in 1979 (16 males and 14 females)and the recaptures of bears marked in 1978 (4 of 6 males and 2 of 4 females).This process yielded popu- lation estimates of 24 males and 25 females older than 3.0 years (Table 1).By lumping sexes,Petersen calculations independently provided an estimate of 49 bears older than 3.0 years (Table 1). Because of the low numbers of marked individuals,the numerical confidence intervals (Ricker 1975)for these estimates were large (Table 1). 210 Corrections to Mark-Recapture Estimates The mark-recapture estimates were based on the assumption that the probabilities·of capture were equal and remained constant through both 1978 and 1979 capture efforts.This assumption may be incorrect for females as there were indications that females with newborn cubs had lower capture probabilities.Only two fe- males with newborn cubs were located during capture.efforts con- ducted during 1978,1979,and 1980 in the study area and adjacent areas.One of these females was trap prone because of her func- tioning radio collar applied the previous year.The other,from a nearby study area,was captured with three newborn cubs in 1978.The following evidence indicates trap shyness by females with newborn cubs relative to the capture techniques utilized in this study: 1.In both 1978 and 1979 only one female with newborn cubs was encountered although females with yearlings were relatively numerous in 1978 (1 with cubs:5 with yearlings),1979 (1:7), and 1980 (0:2).This suggests that the low capture rates of females with newborn cubs were not likely due to low repro- ducti ve rates. - 2.The two females marked in the study area in 1978 that were not recaptured in the 1979 removal effort,both likely had cubs in 1979.Both were in estrus in 1978 and were seen either copulating with or in the company of another bear in 1978. Females with newborn cubs have been reported to remain in the vicini ty of their den sites longer than other bears (Glenn and Miller 1980i Craighead and Craighead 1972).On the Alaska Penin- sula,females with newborn cubs were seldom captured in the spring because they tended to remain in mountainous terrain and near protective cover (Glenn and Miller 1980).Observations in 1978 of a female accompanied by three newborn cubs,indicated 211 I~' that she tended to remain in thickly forested habitats and,con- sequently,was less frequently observed than other radio-collared bears (Ballard ~t al.in press). In recognition of this apparent capture bias,the above capture- recapture estimate was adjusted upwards for the female segment to correct for "trap shyness"of females with newborn cubs.A con- servative adjustment was derived by assuming that the number of females with newborn cubs was equal to the number of captured females with yearlings (7).This adjustment increased the female segment estimate to 33 bears older than 3.0 y (Table 2).This is still probably conservative because it is unlikely that all fe- males with yearlings were captured.However,it should be noted that probable females with newborn cubs were used both in the Petersen "estimate and in the correction to thi s estimate. Sex ratio of captured bears (older than 3.0 y)was 113 males:100 females.In an exploited population where hunters tend to selec- tively harvest males (because males range greater distances,fe- males accompanied by offsprin9 are legally protected,and hunters tend to select large bears),a population with a sex ratio skewed towards females would be expected (Bunnell and Tait 1978).Un- published harvest data from Alaska I s Game Management Uni t 13, which includes the study area,reveal that from 1970 to 1979 males represented 52%of the harvest of bears older than 3.0 y. The "corrected"mark-recapture estimate has a sex ratio (bears older than 3.0 y)of 73 males:100 females;this sex ratio more closely corresponds with the model proposed by Bunnell and Tait (1978)than does the observed sex ratio of captured bears. The number of newborn cubs also required adjustment in a similar manner as the number of females with cubs.Seven females accomp- anied by 12 yearlings were captured in 1979 yielding an average litter size of 1.7 yearlings/female with yearlings.The assump- tion that there were at least as many newborn cubs present as yearlings captured,yielded a conservative correction for newborn. 212 cubs (Table 2).This was conservative because a high rate of cub mortality likely occurs (Glenn et ale 1976)and because all fe- males wi th yearlings were probably not captured. Wi th these adjustments to the female and cub classes,the "cor- rected"Petersen population estimate was 83 bears,of these 57 were bears 3.0 y or older (Table 1). Population Density Estimates To arrive at density estimates using the above populationesti- mates,the area occupied by the removed bears must be determined. Some of the bears captured had portions of their 1978 home ranges outside of the search area,suggesting the total area from which bears were removed was larger than the area searched.However, it appeared reasonable to assume that for each such bear cap- tured,another bear which was only partially resident in the search area was not captured.Assuming that bears with home ranges that are not completely included wi thin the search area have a probability (P)of being captured (where [P]is equivalent to the proportion of their home ranges which is within the search area)and a probability of being missed of (l-P),it is reason- able to use just the search area in making density estimates. Making this assumption and utilizing the search area (3,436 km 2 ) combined with the above estimates of bear populations yielded bear density estimates (Table 1)for each of the above population estimates. The accuracy of the "corrected"mark-recapture density estimate was supported by 1978 home-range data in the study area (Ballard et al.in press).The total area occupied by seven bears (older than 3.0 years)was 1,560 km 2 (overlaps counted only once). A simple proportional extrapolation to the experimental area yielded an estimate of 15 bears aged 3.0 y or older.This figure must be corrected for the presence of unmarked bears.Of the 32 adult bears caught in 1979,only eight (25%)were marked. 213 ~, ,..- I I I r I - r I If it is assumed that the above estimate of 15 bears represents the same proportion of the total population,than the population of bears older than 3.0 y would be 60 bears.This figure is only slightly larger than the "corrected"Petersen estimate (Table 1) and adds credence to this estimate. The "corrected"Petersen density estimate was compared to Brown Bear density estimates elsewhere in North America (Table 2).The estimated density fell about where subjectively expected,lower than in portions of Alaska where Brown Bears have access to salmon or,than in more southern areas of good habitat,but higher than in the Alaskan Brooks Range (Table 2). Biomass Estimation Densi ty estimates provide a measure of comparison between dif- ferent geographic areas within species'range.A more meaningful comparison in terms of relative habitat capacities is biomass which combines density estimates with information on the size of individuals in the population.This parameter has,been infre- quently reported in the literature although,commonly,data are available to calculate biomass. Measured weights were available from 88 Brown Bears captured from 1978 through 1980 in the study area and adjacent areas (Table 3). All bears were captured in the spring (April-June).For each sex,the density estimate lumped bears 3.0 Y or older.There- fore,it was necessary to calculate average weights in the same age categories (Table 3).Similarily,sexes were lumped in cal- culation of average weights of cubs,yearlings,and 2 y-old bears (Table 3). Combining these weights with the "corrected"mark-recapture den- sity estimate (Table 2)yielded a Brown Bear biomass estimate of 262 kg/100 km 2 (1,493 lbs/100 mi 2 ). 214 ACKNOWLEDGEMENTS Financial support for this study was provided by the Game Divi- sion,Alaska Department of Fish and Game (ADF&G).Comparison data reported for 1980 studies were collected during Susitna Darn impact assessment studies financed by the Alaska Power Authori ty. We gratefully acknowledge the assistance of many employees of the Game Division (ADF&G)in capturing and transplanting the Brown Bears~data reduction and tooth sectioning.K.Schneider,D. McKnight,C.Schwartz and C.Gardner (all ADF&G)and D.E.N. Tait reviewed earlier drafts of the manuscript and offered con- structive comments. We especially acknowledge the participation of T.Spraker (ADF&G) who assisted in the bear transplant,and provided technical assistance and advice throughout the project. Much of the success of the bear capturing phase of this project was due to the skills and cooperative attitudes of our spotter plane pilots:Ken Bunch,Al Lee,and Rick Halford,and to the skill and cooperative attitude of our helicopter pilot,Vern Lofstedt. LITERATURE CITED Ballard,W.B.,A.L.Franzmann,T.Spraker,C.Schwartz,and R.o.Peterson.1979.Comparison of techniques utilized to assess moose calf mortality in Alaska.Proceeqings 15th North American Moose Conference,Kenai,Alaska,15:362-387. *Ballard,W.B.,S.Miller,and T.Spraker.1980.Moose Calf Mortality Study,Game Management Unit 13.Alaska Department of Fish and Game.Federal Aid in Wildlife Restoration Project Final Report W-17-9.Juneau.122pp. 215 - .... - ""'"' Ballard,w. range, Bears 95: B.,S.Miller,and T.Spraker. daily movements and reproductive in southcentral Alaska.Canadian In Press.Home biology of Brown Field Naturalist, Bunnell,F.L.,and D.E.N.Tait.1978.Population dynamics of bears and their implicatons.In Population Dynamics of Large Mammals by C.W.Fowler and T.D.Smith (eds.).John Wiley and Sons,New York.(In Press). Craighead,F.C.,Jr.,and J.Craighead.1972.Data on grizzly bear denning acti vi ties and behaviour obtained by using wildlife telemetry.In Bears--Their Biology and Management by S.Herrero red.).IUCN New Series Publication 23:84-106. Glenn,L.P.,J ..W.Lentfer,J.B.Faro,and L.H.Miller.1976. Reproductive biology of female Brown Bears (U rsus arctos), McNeil River ,Alaska.In Bears--Their Biology and Manage- ment (00.R.Pelton,J.W.Lentfer,and G.E.Folk eds.). IUCN New Series Publication 40:381-390. Glenn,L.P.,and L.Miller.1980.Seasonal movements of an Alaska Peninsula brown bear population.In Bears--Their Biology and Management by C.Martinka and K.McArthur (eds.).Bear Biology Association Conference Series No.3:307-312. Martinka, bears C. in J.1974. Glacier Population characteristics National Park,Montana.J. of grizzly Mammalogy 55:21-29. Miller,S.D.,and W.B.Ballard.In press.Homing of trans- planted Alaskan Brown Bears.J.Wildlife Management. 216 Mundy,K.R.D.,and D.R.Flook.1973.Background for managing grizzly bears in the National Parks of Canada.Canadian Wildlife Service Report Series No.22,Ottawa.35pp. Pearson,A.M.1975.The northern Interior Grizzly Bear Ursus arctos L.Canadian Wildlife Service Report Series No.34. 86pp. *Reynolds,H.V.1976.North slope grizzly bear studies. Alaska Fed.Aid in Wildlife Restoration Project W-17-6 and W-17-7.14pp. *Reynolds,H.V.1980.North Slope Grizzly Bear studies. Alaska Federal Aid in Wildlife Restoration Project W-17-11, Job 4.14R.and 4.15R.65pp. Ricker,W.E.1975.Computation and Interpretation of Biologi- cal Statistics of Fish Populations.Bulletin 191 Department of the Environment Fisheries and Marine Service.Ottawa. 382pp. Seber,G.A.F.1973.Estimation of Animal Abundance.Hafner Publishing Company,New York,NY.506pp. .... Troyer,W.A.,R. of a Kodiak 28:769-772. J.Hensel.1964.·Structure and distribution bear population.J.Wildlife Management *Available from Alaska Department of Fish and Game,Division of Game,Subport Building,Juneau,Alaska 99801. 217 - .- 1 J 1 ··--1 1 Table 1.Summary of Brown Bear population and density estimates,upper Susitna River,Alaska. No.of Captures Captured Plus Known Missed bears Uncorrected Petersen Estimate (95%CI) "Corrected ". Petersen Estimate l\J I-'-'co BEAR POPULATION Males (3.0 y+) Females (3.0 y+) 'Both Sexes (3.0 y+) Offspring (0.5-2.5 y) All Bears BEAR DENSITY (km 2 /bear) Both Sexes (3.0 y+) All Bears 17*21** 15*19** 32 40 16 16 48 56 107 86 72 61 24 (9-96) 25 (8-280) 49 (23-136) 70 24 33 57 26 83 60 41 * ** Includes one trap-prone bear that was excluded from mark-recapture calculations. The four adult bears of unknown sex not captured were assigned as two males and two females. 'rable 2.Reported brown bear densities in North America. - 2 Locationkm/bear Source 1.6 Kodiak Island,AK Troyer and Hensel 1964 16 Alaska Peninsula,AK Unpublished data (Glenn, pers.comm.)* 21 Glacier Nat.Park,Montana Martinka 1974 28**Glacier Nat.Park,B.C.Mundy and Flook 1973 23-27 SW Yukon Territory Pearson 1975 tv 41 Upper Susitna R.,Thl.s studyI-'AK I.D 288(42-780)***Western Brooks Range,AK Reynolds 1980 148-260****Eastern Brooks Range,AK Reynolds 1976 *Data refer to a 1800 mi~intensively studied area of the central Alaska Peninsula. **Estimated density,minimum was 1/18 km 2 • ***1/288 km 2 is mean density for the whole ot the Nat.Pet.Reserve,Ak,the range represents values for different habitat types in this reserve where the highest density occurred in an intensively studied experimental area (Reynolds,pers.corom.). ****Highest density (1/148 km 2 )was in an intensively-stud~ed area of relatively high quality habitat,region-wide density was estimated at 1/260 km • ,I I .....J !cJ !cl J ,..."J ~...]j J ]j J 1 J 1 J ,..., XIII.APPENDIX 4 Ballard,W.B.,S.D.Miller,and T.H.Spraker.Horne range, daily movements,and reproductive biology of Brown Bear in southcentral Alaska.Canadian Field -Naturalist 95{):000-000. Abstract:Twe~ty-three radio-collared .adult Brown/Grizzly Bears (Ursus arctos)were studied in the Nelchina Basin of southcentral Alaska during 1978 and 1979.Radio-collared bears were seen on 85.4%of 644 radio locations.Horne ranges ,of adult females aver- aged 408 km 2 ,while those of adult males averaged 769 krn 2 •Daily movement of males averaged 7.7 krn/d.while females averaged 7.0 krn/d.Most bears entered dens in late October and emerged be- tween 9 April and 12 May and therefore were active for half of the year. Most females became reproductively mature at 4.5 y;in three cases females·successfully bred at 3.5 y.A reproductive in- terval Qf 1 Y was reported in one case following loss of a year- ling.offspring.Typical breeding intervals were 3 y.Average size of 17 cub and yearling litters was 1.9:high rates of cub loss were observed.Breeding activity was concentrated in May and June. Relative to most other North American Brown Bear populations, Brown Bears in Interior Alaska had larger home ranges,females reached sexual maturity at younger ages,and weaning of litters occurred earlier. 221 XI I I.APPENDIX 5 Den Si te Characteristics of Prince William Sound Black Bears. by Sterling Miller,Charles Schwartz and Dennis McAllister Black bear dens utilized in winter 1980/81 by bears radio- collared in connection with population identity studies in Prince Wi lliam Sound (Modafferi,in prep.)were located,marked and measured in 1981.Den sites for these same bears in 1981/82 were approximately located by fixed-wing aircraft in January 1982. The purpose of this work was to provide baseline data on charac- teristics of Prince Wi lliam Sound black bear den sites.Such data are valuable in light of increased developmental activities anticipated in the area,especially logging.These observations also provide comparison data to that being collected on the Kenai Peninsula (Schwartz and Franzmann 1981)and along the upper Susitna River (Miller and McAllister in prep). All radio-collared bears were in dens when bears were located by fixed-wing aircraft on 15 April 1981.However,2 bears,both males,had left their dens by 23 April 1981 when dens were marked;only approximate locations and elevations are available for the dens of these 2 males (as well as for all 1981/82 dens). Nine bears,all females,were still in dens on 23 April 1981 and these dens were marked with radio-collars,flagging and/or evi- dent topographic features.1981/82 dens will be similarly marked if time and available funds permi t. Marked dens were visited in summer 1981 and their characteristics were noted and dens were measured.The measurements followed those outlined by Schwartz and Franzmann (1981)with the addition of a subjective characterization of relative quality on a scale from 1 (poor)to 5 (excellent).These data are presented in Table 1 and Fig.1. 222 Of the 9 measured dens,5 were in mature hemlock (Tsuga spp.) forests,a forest type likely to be heavily exploited by in- creased logging efforts.Hollow trees were used as dens by 3 bears denning in hemlock forests (Table 1).In 1981/82 all 10 dens tentatively located were in hemlock forests or hemlock asso- ciations (Table 2). Interestingly,8 of the 9 dens examined in 1981 were in natural cavities (3 in trees,3 in rock caves,and 2 under large boulders on talus slopes (Table l)j only 1 den was excavated by a radio- collared black bear. In 7 cases a determination or reasonable guess could be made on whether an examined den had been previously used by a black bear. In 4 of these previous use by black bears was evident or sus- pected (Table 1). Frequency of reuse of the same den by the same individual ap- peared low,although individual bears tended to den in the same general vicinity in successive years.None of the dens visited in 1981 was reused by radio-collared bears in 1982,although one bear (144)denned close enough to its previous den (0.25 miles) to be wi thin the range of radio-tracking and plotting errors (Table 2).Den site locations prior to 1980/81 are available for only a few individuals (Modafferi ,pers.commun.).Female 101 apparently used the same den in 1977/78 when she entered the den with a single cub as she did in 1980/81 when she entered with 3 cubsj she probably used the same den in 1979/80 but denned else- where in 1980/81,and apparently,in 1976/77.No den location was recorded for this bear in 1978/79.Two bears with radio- tracking histories (106 and 143)used different dens,1-6 miles distant,in earlier years when den sites were approximately located (1977/78 and 1979/80 for 106 and 1977/78 for 143).The mean distance between dens for 10 individuals in 1980/81 and 1981/82 was 0.9 miles (0.25-1.88)(Table 2). 223 - .-, - ..... ,~ The time bears spent in 1980/81 dens could not be determined as the last flight in 1980 was on 29 September at which time all bears were still out.Emergence from dens seemed concentrated in the first 2 weeks of May for females and the last two weeks of April for the 2 males (Table 3). 224 REFERENCES CITED Miller,S.and D.McAllister.In prep.Brown and Black Bear Studies.Annual Report,Subtask 7.11 (Wildlife Ecology Studies),ADF&G Susitna Hydroelectric Project Impact Assess- ment. Schwartz,C.and A.Franzmann.1981.Black Bear Predation on r- Moose.Project Progress Report,Federal Aid in Wildlife Restoration Project W-17-2,Job 17.3R.43 pp. - 225 ""'"' - Figure 1. N ----.dug cavity --natural cavity Aspect of 1980/81 black bear dens In Prince William Sound.Alaska. 226 -----------------------------------'-..,..,--- Table 1.Characteristics of Black Bear Dlins in l'rince William Sound.1980-81. Eleva-Entrance Chamber Total Prevo Den Bear Age @ tion Slope Aspect Ve etation %canopy Ht.Width Ln.Widtb Ht.length Used?"Quality"Location No.No.exit ft.(degree)(True N)g tree cover (cm)(em) (cm)(cm)(cm)_(~)""&type NATURAL CAVITIES Female w/offspring (at exit) w/3 yearlings 101 9 375 10,352 Alpine tundra 0 38 47 216 160 96 800 yes....3 Blsckstone Bay ~Rock talus Females wlo offspring 2 106 19 450 14 27 Hemlock 30 65 55 71 '80 90 94 No?4 Blackstone Bay Hollow tree 3 143 7 500 45 327 Hemlock 60 46 26 88 71 74 198 No?2 C~chrane Bsy Hollow tree 5 144 7 600 40 123 Hemlock 30 37 48 67 62 -89 -7-4 Cochrsne Bay Hollow tree 6 169 14 300 26 330 Hemlock 20 55 104 175 126 67 308 Yes 3 Cochrane Bay Rock cave 7 148 3 400 SO 187 AlderlSalmon-0 34 71 73 134 65 122 -1-3 Cui rose Passage berry Rock cave 8 147 17 900 55 122 Hemlock 80 178 42 128 114 118 980 Yea 3 .Culrose Passage N Rock talu8 N 10 149 11 1250 60 187 Alpine tundra 0 43 59 86 86 53 268 Yes?3 Cochrane Bay -.J Rock cave Hales 11 165 7 250 - - Spruce slight --------Cochrane Bay (den not msrked approx as besr out by 23 April) 12 146 9 350 --Alder(?)0 --------King8 Bay (den not marked a8 bear out by 23 April) approx DUG CAVITIES. Females wlo offspring 9 142 12 1300 52 185 Alder 0 36 52 70 129 92 80 No 3 Cochrane Bay "Same bear used the den in 77/78 (w/l ylg.).and probably in 79/80;not in 8arne den in 76/77,unknown den location in 78/79. ""Subjective characteristic8 of quality,I-poor and 5-excellent. I I J J )_I _I r Table 2.Characteristics of black bear dens in Prince William Sound,1981/82.(Based on locations from fixed wing aircraft on 4 Jan.1982). Distance from 80/81 Approximate den (Table 1)Elevation BEAR ID (Miles)(ft.)Aspect Slope Habitat 101 0.81 450 NW Steep Hemlock-alder- rock 106 0.94 10 Flat Flat Alder-hemlock 143 0.53 80 NW Moderate Hemlock 144 0.25 750 SE Steep Hemlock-alder 169 1.88 400 NW Steep Hemlock-alder- rock 148 0.44 400 SW Moderate Hemlock-alder 147 1.19 650 S Moderate Hemlock 142 1.75 500 1?E Steep Hemlock-alder 149 0.81 850 N Steep Hemlock 146 0.60 300 SE Moderate Hemlock 165 Not located in 1982. Mean 0.92 439 S.D.0.54 269 .Range 0.25-1.88 10-850 228 rable 3.Den entrance and emergence dates of radio-collared Black Bears in Prince William Sound,winter of 1980/81. 229 - .- I XI I I.APPENDIX 6 Preliminary results testing technique to chemically differentiate between scats of black and brown bear. Enid Goodwin and Sterling Miller Alaska Department of Fish and Game A technique for identification of field collected carnivore scats by recovery of bile acids through thin-layer chromatography (TLC) has recently been developed (Major et al.1980).This method was applied to known samples of brown bear and black bear feces,two types of scats which cannot be distinguished visually.Samples from two brown bears and three black bears were used in the preliminary experiment.Samples were prepared for TLC according to Major et al.(1980)and the plates were examined under long- wave (366 nm)and short-wave (254 nm)ultraviolet light as well as visually under white light.Because of the lack of bile acid standards,along with other limitations due to the preliminary testing aspect of the experiment,resul tsobtained were neces- sarily tentative.Nevertheless,results indicate possible dif- ferences between the two scat types.Further experimentation to fully delineate the nature of bile acid differentiation between brown and black bear fecal samples is recommended . Three compounds with Rf values (ratio of the distance the solute moved to the distance traveled by the solvent front)comparable tC)Rf values of known bile acids (Major et al.1980)were found on the test TLC plates.These were lithocholic acid (Rf =0.75), chenodeoxycholic acid (Rf =0.47)and cholic acid (Rf =0.15). Two other unidentified compounds located on the bear scat test plates had Rf's compa.rable to unidentified compounds listed by Major et al.(1980):Rf =0.87 (brown and black bear)and Rf =0.72 (brown bear).In addition,all samples tested showed a 230 compound with an Rf value of 0.06,and both brown bear samples showed a compound wi th an Rf of 0.97. Of the components corresponding in Rf value to those of known bile acids,the black bear samples showed lithocholic acidi brown bear samples showed chenodeoxycholic acid,and both types showed cholic acid.Further testing is needed to determine what,if any,variation exists wi thin species,and also to determine if the above indications are independent of diet.Tentative results indicate that the presence of chenodeoxycholic acid in brown bears and the presence of lithocholic acid in black bears may be a key to identification. Brown bear samples showed a component (Rf =0.97)which did not appear in the black bear samples.While Major et al.(1980) stated'that compounds traveling above lithocholic acid (Rf =0.75)were probably not bile acids,this component may still provide an identification key if found to be cons"tant wi thin the species and absent wi thin black bears. The differences between the two scat types are presented in Table 1.The most striking aspects between brown and black bear samples tentatively appear to be the presence of chenodeoxycholic acid (Rf =0.47)and two unidentified compounds (Rf =0.72 and 0.97,respectively)in brown bears with a corresponding absence in black beari and the presence of lithocholic acid (Rf =0.75) in black bears wi th a corresponding absence in brown bear scats. 231 - - - - .-,Summary of TLC results on bi le':"acid and unidentified steroid recovery I brown and black bear fecal samples. - Rf Brown Bear Black Bear Unidentified 0.06 X X Cholic Acid 0.15 X X Chenodeoxycholic Acid 0.47 X Unidentified 0.72 X Lithocholic Acid 0.75 X Unidentfied 0.87 X X Unidentified 0.90 X X Unidentified 0.97 X 232 r .• LITERATURE CITED.. Major,M.,M.K.Johnson,W.S.Davis,and To F.Kellogg. 1980.Identifying Scats by Recovery of Bile Acids. J.Wi ldl.Manage.44 (1):290-293. 233 - - '~