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ALASKA POWER AUTHORITY
SUSITNA HYDROELECTRIC PROJECT
ENVIRONMENTAL STUDIES ANNUAL REPORT
Subtask 7.11 -Big Game
July 1981
by
TERRESTRIAL ENVIRONMENTAL SPECIALISTS,Inc.
Phoenix,New York 13135
for
.-ACRES AMERICAN,INCORPORATED
Liberty Bank Building,Main at Court
Buffalo,New York 14202
ARLIS
Alaska Resources
Library &InJormation Services
.Anchorage,Alaska
.....
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SUMMARY
This report embodies the initial findings with respect to the
populations of big game --bears~hoofed mammals,wolf and wolverine
in the Susitna basin,and the potential impacts on these populations by
the proposed Susitna Hydroelectric Project.It will be augmented by
the work of another year before the final report of Phase I is
prepared.
Biometrics and Data Processing
Field investigations of big game are being facilitated by the use of
radio-collars.Relocations involve both repeated habitat descriptions
and repeated physical locations,a body of data requiring initial
standardization and periodic computer-aided analysis.Technical and
conceptual problems associated with those requirements are outlined and
proposed solutions presented.Computer resource requirements are
identified and the progress to date in acquiring those resources and
developing a production system is reported.
Brown and Black Bear
Both black bear (Ursus americanus)and brown bear (Q.arctos)
populations in the vicinity of the proposed Susitna hydroelectric dams
appear to be healthy and productive.Brown bears occur throughout the
study area while black bears appear largely confined to the finger of
forested habitat along the Susitna River.This finger becomes
progressivl~ly narrower proceeding upstream.In 1980,27 brown bears
and 27 black bears were captured,utilizing helicopter darting
techniques.Adults were marked and radio-collared and periodically
relocated.A total of 143 point locations were obtained for brown
bears in 1980,120 of these from 15 radio-collared individuals.A
total of 2:29 poi nt locations were obtai ned for bl ack bears 1lRttS181
of these from 23 radio-collared individuals.A1
aska Resources .
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Winter denning sites (1980-81)of nine radio-collared brown bears are
we 11 abovE~the proposed impoundment 1eve 1.Brown bear uses of areas
di rectly "impacted by proposed impoundments appeared greatest in the
early spr'ing following emergence from dens.We speculate that brown
bears may have been attracted to these areas in the spririg by the early
availability of both vegetable and animal foods.Important vegetable
foods may include berries from the previous year,tubers,fresh
grasses,iind sedges which may be available earlier in .these areas
because of earlier snow melt.Animal foods utilized in these areas may
be winter··killed or weakened moose and,somewhat later,moose calves.
The proposed impoundments wi 11 presumably reduce thi s spring habitat.
The most interior run of salmon known in the study area occurs at
Prairie Creek,a feeder stream running from Stephan Lake to the
Talkeetna River.Four of 11 radio-collared brown bears moved to
Prairie Creek during the summer salmon run.No fewer than 30 brown
bears fished here in 1980.Brown bear movements to or from Prairie
Creek may be inhibited by impoundments or access routes,thereby
reducing the availability of this salmon resource to an appreciable
proportion of the bears in the study area.
Studies in the headwaters of the Susitna River conducted in 1979
estimated a brown bear density of 1 bear/41-62 km 2 .We conjecture
that brown bear density in the impoundment area is roughly comparable
to that in the area of the 1979 study.If so,the impoundment study
area of 3,500 km 2 contains approximately 70 brown bears.
Capture and relocation records for black bears suggested that black
bear distribution in 1980 was largely confined to or near the spruce
forests found in the vicinity of the Susitna River and its major
tributaries.These are the habitats which will be maximally impacted
by the proposed impoundments;the restricted nature of black bear
distribution in the study area suggests that these populations may be
highly vulnerable to habitat losses by inundation as well as by
disturbances associated with construction and improved access.
-Black bear use within the spruce habitats was most prevalent in the
early spring.In late summer 1980 many black bears moved to the more
open shrublands adjacent to the spruce forests.This movement appeared
motivated by the prevalence of berries (Vaccinium)in these open
areas.
Black bears crossed the Susitna River more frequently than brown bears.
This result probably reflects the relative proximity of black bear home
ranges to the river.The motivation or importance of these river
crossings for black bears is not known,nor is it yet known whether the
proposed impoundments would represent a si gnifi cant barri er to such
crossings.
All five of the radio-collared black bears with 1980 dens in the
vicinity of the Watana impoundment denned below 2,200 feet elevation,
the approximate proposed high water mark of the Watana impoundment.
Two of nine black bears denning in the vicinity of the Devil Canyon
impoundment denned below the approximate proposed high watermark
(1,450 feet);the average elevation of nine of these dens was 1,935
feet (1,300-2,750 feet).Nine of 14 black bear den sites were in
spruce habitats and five were "in shrubland habitats adjacent to spruce
habitats.Thus it seems clear that many den sites utilized by black
bear in 1980 would be inundated·by the proposed impoundments.The
impact of this den inundation on black bear populations is as yet
unknown.In 1981 these den sites will be visited and their
characteristics described.
Bl ack bear-density appeared vari able throughout the study area.A very
rough estimate of 1 bear/4.1 km 2 was offered for one area of
r~latively high density.
Bear studies in the remainder of Phase I will concentrate on collection
of additional evidence on bear distribution and movements in the study
area.Efforts wi 11 be made to increase the proport i on of marked
animals in the population throughout Phase I and Phase II.Among other
things this will ultimately permit a more accurate estimate of bear
populations in the impact area.
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Caribou
The Nelchina caribou herd which occupies a range of about 20,000 mi 2
in southcentral Alaska has been important to hunters because of its
size and proximity to population centers.The proposed Susitna
impoundments would inundate a very small portion of apparently low
quality caribou habitat.However,concern has been expressed that the
impoundments and associated development might serve as barriers to
caribou movement,increase mortality,decrease use of nearby areas and
tend to isolate "subherds".Overall objectives of the current study
are to evaluate potential impacts of the proposed hydroelectric project
on Nelchina caribou and to suggest possible mitigating measures.
Because of the changeable nature of caribou movement patterns,short-
term studies of distribution and movements must be tempered with
historical perspective.Fortunately the Nelchina herd has been studied
continuously since about 1948 and records previous to that time have
been reviewed.The primary methodology for this study is the
repetitive relocation of radio-collared caribou.Population estimates
are made with a modified version of the aerial photo-direct count-
extrapolation census procedure.
Late winter distribution of caribou in 1980 was in the Chistochina-
Gakona River drainages,the western foothills of the Alphabet Hills and
the Lake Louise Flat.The two main routes to the traditional calving
grounds in the northern foothills of the Talkeetna Mountains were
across the Lake Louise Flat into the calving area via the lower Oshetna
River and across the Susitna River in the area from Deadman Creek to
the bi g be!nd of the Sus itna.Cal vi ng occurred between the Oshetna
River and Kosina Creek from 3,000 to 4,500 feet elevation.The main
summering concentration of Nelchina caribou occurred ifF the northern
and eastern slopes of the Talkeetna Mountains between Tsisi Creek and
Crooked Creek,primarily between 4,000 and 6,000 feet.Most caribou
were located on the Lake Louise Flat during the rut.During early
winter the!herd was split in two groups;one in the Slide Mountain-
Little Nelchina River area and the other was spread from the
Chistochina River west to the Gakona River through the Alphabet Hills
to the Maclaren River.
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It appeared (based on only 8 months data)that at least two small
subherds w'ith separate calving areas existed,one in the upper
Talkeetna River and one in the upper Nenana-Susitna drainages.
-Insufficient data were available to evaluate the status of the Chunilna
Hills group.
The Nelchina caribou herd was estimated to contain 18,558 animals in
October 1980.Herd composition was estimated at 49.0 percent cows,
30.3 percent bulls and 20.7 percent calves.
It was apparent from historical records (and to a lesser degree from
movements of radio-collared animals)that the proposed Watana
impoundment would intersect a major migratory route.It seems possible
that the impoundment could be a barrier to movement and a potential
source of mortality,particularly during spring migration when females
are in relatively poor condition and various combinations of ice
shelving,ice sheets,overflow,ice floes and wind-blown glare ice
could occulr.The impoundment could tend to isolate the northwestern
corner of the Nelchina range,an area which has been heavily used by
caribou in the past.Access routes,roads,railroads,and air fields,
could affect caribou movements depending on locations and amount of
use.The proximity of the calving grounds to theWatana impoundment is
of concern because of the traditional fidelity to this calving ground
and the possibility that increased human access and activity could
result in reduced use.
The Devil Canyon dam site and impoundment appears to have virtually no
potential to impact Nelchina caribou.Conversely the Watana site would
almost certainly have negative impacts although the extent cannot yet
be predi ctled.
Dall Sheep
No sheep were radio-collared,but an aerial survey of known or
suspected Dall sheep habitat in the vicinity of the proposed Susitna
Hydroelectric Project was conducted in July 1980 to delineate sheep
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distribution.Three discrete areas of habitat were identified.Sheep
in all three areas may be subject to disturbance from construction
activities,helicopter traffic or access routes,although disturbance
may be reduced or e1imi nated through routi ng or scheduli ng of human
activities.
Sheep occupying the Watana Creek Hills were observed in lowland
habitats that might be inundated by the proposed Watana impoundment.
Little is known about the importance of this habitat to the population
but it is possible that some attractant such as a mineral lick occurs
there.If so,assessment of the impact of the Sus itna Project on thi s
sheep population will be more complex than anticipated and an expansion
of the scope of the study will be necessary.
Wolverine
During April and May 1980,five adult wolverine were captured and four
(3 males,1 female)were radio-collared.Eighty-six radio locations
were obtained during 1980.
Yearly horne range sizes for two males were 399 km 2 and 272 km 2 .
The summer home range for a lactating female was 86 km 2 .Summer
movement patterns of the three male wolverine seemed to be influenced
by the.Susitna River.Only three occurrences of river crossings were
documented during the studi period.Within their home ranges,all
radio-collared wolverine showed a fidelity toward upland shrub (willow-
birch)habitats and toward southerly and westerly slopes.
All three male wolverine displayed a seasonal change in their home _
range usage.Preferences are presumably related to the wolverine
breeding season and timing of ground squirrel emergence and caribou
calving.Ground tracking during May and December,1980 indicated
wolverine dependence on small mammals for food.
Potential impacts on wolverine by the Susitna Hydroelectric Project
include the following:loss of habitat due to inundation and
construction (including roads and transmission lines),a probable
reduction in prey densities,increased competition with other
scavengers and predators,and a readjustment of home range size and
seasonal movements.
There is evidence that wolverine are intolerant of human disturbance.
Impacts from disturbance might be influenced by timing and placement of
construction activities.For example,activities on southerly and
westerly slopes are more likely to affect wolverines than are those on
northerly or easterly slopes.
Downstream Moose
Moose populations in the Susitna Valley were relatively small in the
early 1900's.Since then,man has altered the habitat thro~gh fires,
1oggi ng,and farmi ng,and the moose have increased.The lower Sus itna
River moose population does not appear to mix with the Matanuska Valley
or Peters-Dutch Hills populations,but more study of movements is
necessary.
Deep snow in winter has been documented as a cause of migration from
rut and post rut areas in the Talkeetna Mountain foothills to the
Susitna River and vicinity,but no studies have determined the relative
use by moose of the Susitna River floodplain versus upland habitats
near the river.The present study focusses on the seasonal
distribution of moose populations using the lower Susitna,the relative
magnitude of s~asona1 moose use of the Susitna floodplain and the
relative use of associated habitats.
In April 1980,10 moose were immobil i zed and equipped with radi 0
collars.Various biological specimens were taken from the moose at the
capture site.Periodic relocation flights were conducted to determine
each moose's location and activity,and association with other moose
and with habitat type.
The small sample of marked moose,and the difficulty of spotting
unmarked moose in the timber,made determination of major seasonal
patterns of population distribution impracticable,although a variety
of individual patterns was noted.More work on seasonal movement and
distribution is needed.
A preliminary survey of browse distribution and use along the river
showed a mean of 1.4 browse plants per square meter.Willow,most
prevalent in early successional stages,was consistently well browsed.
Birch,near the river,was also a preferred forage.Cottonwood,rose,
and highbush cranberry were less used,and alder was largely unused.
Potential for managing downstram plant communities for increased
production of moose forage,if this proves a desirable avenue of
mitigation,appears excellent.
Upstream Moose
Compared to caribou,most moose make relatively short seasonal
movements.Thus far,both resident and mi gratory sub-popul at ions have
been identified.Presumably these both require the same general sort
of winter range.Since the Watana and Devil Canyon impoundments will
cover the lowest portion of the landscape,some present moose winter
range will be inundated.
The size of spring-fall home ranges of cows with calves was found to be
relatively large (16.8 km 2)compared to findings el~ewhere (2.2 -
16.9 km 2 , 7 studies).Although fidelity to seasonal ranges by
marked individuals was high,some changed seasonal ranges,especially
in winter.Seasonal use of plant communities corresponded to
elevational distribution of plant communities and indicate seasonal
elevational preferences of migratory moose.
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Wolves
Intensive wolf·studies have provided a good understanding of population
densities,and use of prey.Population densities in Game Management
Unit 13 have!varied over recent years from 97 to 315 km 2/wo"lf.
There has been some decline in wolf populations lately,presumably due
to a heavy take by humans ,but a strong tendency toward hi gh
reproductive gain following a spring of low wolf population indicates
that the wolf population has marked recuperative powers.
Foods taken by wolves include moose (the major prey),caribou,beaver,
snowshoe hare,and smaller mammals.Moose and caribou winter
vulnerability to wolf predation is greater when snow is deeper.On the
average,a wolf pack takes prey in winter at the rate of about 5-7
kg/day/wolf .
TABLE OF CONTENTS
SUMMARY
1
1
2
1.4
1.5
1.6
1.7
1.8
1 -INTRODUCTION -
1.1 ..Big Game Biometrics and Data Processing - - - - ---
1.2 ..Brown and Bl ack Bear Studi es - - - - - - - - -
1.3 -Caribou Herd Identity,Migration Patterns and
Habitat Use - - - - - - - - - - - - - - -5
-Dall Sheep - - - - - - - - - - - - - - --- - - - - 7
-Wolverine - - - - - - - - - - - - - - - - - - - - - - 8
-Downstream Moose - - - - - - - - - - - - - - - - - - 9
-Upstream Moose - - - - - - - - - - - - - - -12
-Wolf Studies - - - - - - - - -- - - - -13
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2 -METHODOLOGY - - - - - - - - - - - - - - - - - - - - - -15
2.1 -Data Processing - - - - - - - - - - - - --- --- -15
2.1.1 -Animal Distribution Analyses - - - - - - - - - - -15
2.1.2 -Habitat Selectivity Analyses - - - - - - - - - - -15
2.1.3 -Species Interaction Analyses - - - - - - - -16
2.1.4 -Basic Data Processing and Analysis - - - --- - -16
2.2 -Area of Study - - - - - - - - - - - - - - - - - - - -16
2.2.1 -Black and Brown Bears - - - - - - - - - - - - - - -17
2.2.2 -Caribou - - - - - - - - - - - - - - - - - - - - - -18
2.2.3 -Ball Sheep - - - - - - - - - - - - - - - - - - - -18
2.2.4 -Wolverine - - - - - - - - - - - - - - - - - - - --18
2.2.5 -Downstream Moose ---- - - - - - - - - - - -- -19
2.2.6 -Upstream Moose - - - - ----- -- - - - - - - -19
2.2.7 -Wolves - - - - - - - - - - - - - - - - - - - - - -19
2.3 -Radio-telemetry - - - - - - - - - - --- - - - - --20
2~3.1 -Black and Brown Bears - - - - - - - - - - - - - - -20
2.3.2 -Caribou - - - - - - - - - - - - - ----- - - - -22
2.3.3 -Dall Sheep - - - - - - - - - - - - - - - - - ---23
2.3.4 -Wolverine --- - - - - - - - - - - - - - - - - - -23
2.3.5 -Downstream Moose - - - - - - - - - - - - - - - - -25
2.3.6 -Upstream Moose - - - - - - - - - - - - - - - - - -26
2.3.7 -Wolves - - - - - - - - - - - - - - - - - - ----27
2.4 -Population Studies - - - - - - - - - - - - - - - - -27
2.4.1 -B1 ack and Brown Bears - - - - - - - - - - -----27
2.4.2 -Caribou - - - - - - - - - - - - - - - - - - - - - -28
2.4.3 -Da11 Sheep - - - - - - - - - - - - - - - - - - - -29
2.4.4 -Wolverine - - - - - - - - - - - - - - - - - - - - -30
2.4.5 -Downstream Moose - - - - - - - - - - - - - - - - -30
2.4.6 -Upstream Moose - - - - - - - - - - - - - - - - - -30
2.4.7 -Wolves - - - - - - - - - - - - - - - - - - - - - -31
2.5-Food Availabil ity and Use - - - - - - - - - - ----31
2.5.1 -Downstream Moose - - - - - - - - - - - - - - - - -32
3 -RESULTS AND DISCUSSION - - - - - - - - - - - - - - - - - - -34
3.1 -Data Processing - - - - - - - - - - - - - - - - - - -34
3.1.1 -Data Entry of Radio Telemetry Observations - - - -34
3.1.2 -Data Analysis of Location Information - - - - - - -35
3.1.3 -Habitat Selectivity Analyses - - - - - - - - - - -37
3.1.4 -Species Interaction Analyses - - - - - - - - - - -40
TABLE OF CONTENTS - 2
3.2 -
3.2.1
.3.2.2
3.2.3
3.2.4
3.2.5
3.2.6
3.3 -
3.3.1
3.3.2
3.3.3
3.3.4
3.3.5
3.4 -
3.4.1
3.4.2
3.4.3
3.4.4
3.5 -
3.5.1
3.5.2
3.5.3
3.6 -
3.6.1
3.6.2
3.6.3
3.7 -
3.7.1
3.7.2
3.7.3
3.8 -
3.8.1
3.8.2
3.8.3
Black and Brown Bears-- - - - - -...- - - - - - - -40
-Sex and Age Composition of Captured Animals - - - -40
-Brown Bear Seasonal Distribution and Movements - -43
-Brown Bear Density - - - - - - - - - - - - - - - -51
-Black Bear Seasonal Distribution and Movements - -53
-Black Bear Density - - - - - - - - - - - -61
...Needs for Further Study - - - - - - - - - - - -63
Caribou - - - - - - - - - - - - -64
-Distribution and Movements - - - - - - - - - -64
-Subherds - - - - - - - - - - - - - - - - - - -67
-Population Size and Composition - - - - - - - -69
-Habitat Selection - - - -...- - - - - -...- - -72
-Planned Activities for Remainder of Phase I - - - -73
DallSheep ---- - - - - - -- - - -...- - -74
-Watana Hills - - - - - - - - - - - - - - - -74
-Mount Watana - - - - - - - - - - - - - - - -76
-Portage-Tsusena Creek - - - - - - - - - - - - - - -76
-Hunter Use - - - - - - - - - - - - - - - - -76
Wo 1veri ne - - - - - - - - - - - - - - - - - - -77
-Movements and Habitat Selection - - - - - - - - - -77
-Ground Tracking - - - - - - - - - - - - - - - - - -84
-Carcass Collection and Analysis - - - - - - -84
Downstream Moose - - - - - -- - - - - -84
-Population Distribution - -- - - - - -85
-Use of Riverine Habitats -87
-Browse Utilization - - - -88
Upstream Moose - - - - - - - - - - - - - -89
-Home Range - - - - --...- - -89
-Plant Community Use - - - - - - - - -91
-Popu 1at i on I dent ity ...- - - - - - - - - - - - -91
Wolves - - - - - - - - - - - - - - - - - - - - -94
-Packs and Pack Attributes - - - - - - - - - - -94
-RelationstoPrey---------94
-Population Studies - - - - -96
4 -IMPACT ASSESSMENT - - - - - -
4.1 -Construction Impacts - - - -
4.1.1 -Watana Dam and Reservoir - - - - - - - - - - -
4.1.2 -Devil Canyon Dam and Reservoir - - - - - - - - - -
4.1.3 -Access Road - - - - - - -.--- - - - - - - -
4.1.4 ~Transmission Facilities - - - - - - - - - - - -
4.2 -Operation Impacts - - - - - - - -- - - -
4.2.1 -Watana Dam and Reservoir - - -
4.2.2 -Devil Canyon Dam and Reservoir
4.2.3 -Access Road - - - - - - -
4.2.4 -Transmission Facilities -
4.2.5 -Downstream Flow Regime - - - - -
101
101
101
102
104
104
104
104
110
110
111
111
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TABLE OF CONTENTS - 3
5 -MITIGATION - - - - - - - - - - - -
5.1 -Cantralof Human Activity -
5.2 -Siting ----- - - - - -
5.3 -Plant Community Management
6 -REFERENCES - - - - - -
7 -AUTHORITIES CONTACTED
112
112
112
112
114
130
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LIST OF TABLES
56 -
58
59
78
70
71
75
97
44
46
47
80
62
81
90
92
-79
98
100
- - - -49
- - - - -52
54
8
1 -Brown Bears Captured in the Spring of 1980 - - - - - -41
2 -Black Bears Captured in the Spring of 1980 - - - - - - - - -42
3 -Sex and Age Composition of Marked Brown Bears
Remaining in the Study Area in October 1980 - - - -
4 -Sex and Age Composition of Marked Black Bears
Remaining in the Study Area in October 1980 - - - - - - -45
5 -Average Spring Ages,in Years,of Susitna Area
Brown Bear Sub-populations 3 Years or Older
6 -Brown Bear Relocation Records for 1980 -
7 -Capture and Qen Site Locations for Brown Bears
Captured in 1980 - - - - - ---- - -
Reported Brown Bear Population Densities in
North America - - - - - - - - - - - -
9 -Black Bear Relocation Records for 1980 - - - - - -
10 -Monthly Occurrence in Spruce Habitats for 23 Radio-
collared Black Bears in the Susitna Study Area - - -
11 -Black Bear Capture Sites,1980 - - - - --- - - - - -
12 -Black Bear Den Sites,1980 - - - - - - - - - - - -
13 -Black Bear Population Densities in Various North
American Localities - - - ----- - - - - - -
14 -Nelchina Caribou Post-Calving and Age Composition
Data - - - - - - - - - - - - - - - - - - - - - -
15 -Nelchina Caribou Fall Sex and Age Composition Data - -
16 -Compilation of Highest Yearly Counts Completed in
Watana Hills Sheep Trend Count Data - - - - - -
17 -Tagging Location and Physical Measurements of
Wolverine Captured in Susitna River Basin 1980 -
18 -Drug Type,Dosage,and Subsequent Induction Time for
Wolverine Captured inSusitna River Basin,1980
19 -Summary of Home Range Size for Four Radio-collared
Wolverine in Susitna River Basin,1980 - - - - -
20 -Comparison of Annual Wolverine Harvests from
1962-63 through 1979-80 in Game Management Unit 13
21 -Reported Home Range Size,Cows with Calves - - - - - -
22 -Percentage Utilization of Plant Communities by Month -
23 -Summary of Predation Statistics Derived from
Intensive Radio-monitoring of the Susitna and
Tyone Wolf Packs - - - - - - - - - ---- - - -
24,-Estimated Number of Prey Individuals Consumed by
Game Management Unit 13 Wolves - - - - - - - - - - - -
25 -Summary of Reported Wolf Densities for North America -
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1 -INTRODUCTION
Moose,caribou,brown and black bears,Da11 sheep,wolves and wolverine
constitute the big game animals of the Susitna basin and the subject of
this report.These species have long been of concern to the Alaska
Department ofFish and Game,whose bi~logists have pursued their study
within,among other places,the Susitna basin,which constitutes part
of Game Management Unit 13.Because of this experience,and the
expertise that it has engendered,the AFD&G biologists were the logical
choice to carry out the more intensive field investigations
necessitated by the proposal to establish a hydropower complex on the
Susitna River.Their program of investigation,carried out under the
supervision of Karl Schneider,is impressive in concept and execution.
This document is largely a compilation by Or.Richard Taber of the 1980
reports produced by ADF&G.
1.1 -~Game Biometrics and Data Processing:SuzAnne Miller and
Danny Anctil
The objective of the biometrics and data processing project is to
provide technical assistance in the quantitative and information-
management aspects of the big game studies.The time constraints,
volumes of data,and reporting requirements associated with the Susitna
Hydroelectric Project Impact Assessment Studies mandate the development
of efficient and accurate means of recording,analyzing,displaying and
reporting the data collected.This can only be done by means of
electronic data management systems.
Four major aspects of the big game studies have been identified as
requiring support from the biometrics and data processing project:
(a)Animal distribution analysis.
(b)Habitat selectivity analysis.
(c)Species interaction analysis.
(d)Basic data processing and analysis.
1.2 -Brown and Black Bear Studies:Sterling Miller and Dennis
McA 11 i ster.
Black bear (Ursus americanus)and brown bear (!!.arctos)are widely
distributed and abundant in Alaska.Black bear distribution in Alaska
cO'incides closely with the distribution of forests~with the most
abundant populations occurring in "open"forests rather than heavy
timber;extensive open areas are usually avoided.Brown bears seem
best adapted to open areas of tundra or grasslands although~like black
bears,they inhabit a variety of different habitats in Alaska.
Taxonomically there is only one species of brown-grizzly bear.In
common usage the term brown bear is ut il ized to refer to southern and
coastal populations of this species and grizzly bear refers to northern
and interior'populations.Typically "brown·!bears are larger and
darker than lI gr izzlyJ'bears.The brown-grizzly bears along the Susitna
River described in this report are,most appropriately~referred to as
brown bears.
Black bears in Alaska tend to be smaller than in ~any areas of the
contiguous United States~most commonly they weigh 100-200 lbs.
Several color phases of black bears are known~the Susitna population
includes individuals that are black,cinnamon~and dark brown.
In Alaska,both species of bears spend the winter in dens.Black bears
use a variety of den sites and structures ranging from substantial
excavations on hillsides or under logs and trees to~less commonly~
simple and relatively shelterless sites.Brown bears most commonly den
in well excavated holes on high mountain slopes.The denning period
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for both species typically runs from October through April or May but
annual,geographic,and individual variations are common.In the
Susitna arecl a 1imited number of observati ons suggest that bl ack bears
enter dens E~ar 1i er and emerge 1ater th an brown bears (Mi 11 er
unpublished data).
Brown bears are more aggressive and dangerous to man than black bears.
This may be the result of evolution in a more open environment without
trees to serve as escape habitat and the correspond i ng 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 associated 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 incompatible
with increasing human presence except in a few parks where bears are
given a legal priority over human development activities.
Both species of bears are omnivorous,eating a wide variety of grasses,
sedges,other herbaceous plants,roots and berries as well as animal
protei n when avail ab le.Popul at ions with access to salmon may heavily
uti~ize this resource during portions of the year.Brown bears have
recently been shown to be significant predators on moose calves in the
upper Susitna-Nelchina basin area (Ballard et al.1980).
Brown bear research has been undertaken since 1978 in the Nelchina and
Susitna River basins.This research has concentrated on the magnitude
and effects of brown bear predation on moose but considerable life
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history
1981).
1948 to
levels.
data were al so collected (Ball ard et al.1980,Spraker et al.
In this region federal predator control programs conducted from
1953 are suspected to have reduced bear populations to low
In the last 20 years brown bear populations have increased and the
current population appears to be abundant,young and productive.Fall
harvests in the period 1970-1979 averaged 61 bears/year (30-84 bears/
year)i n Al aska IS Game Management Unit (GMU)13.·This level of harvest
is suspected to be less than the maximum sustainable yield of this
population.In 1980 a May 10th thru 25th bear season was held;the
same season will be held in 1981.
Unt il the present study,bl ack bear research has not been conducted in
the Susitna or Nelchina River basins.The abundance of black bears and
relatively light hunting pressure in these areas permits a year-long
open hunt i ng season and an annual bag 1imit of three bears.An annual
average of 63 black bears have been taken in GMU 13 from 1973-1979
(58-70 bears/year).Rel ative to brown bears,black bears are highly
productive and numerous and this population could sustain higher levels
of harvest.
The overall objectives of bl ack bear and brown bear studies mandated by
proposed hydroelectric development on the Susitna River are:
liTo determine the distribution and abundance of black and
brown bears in the vicinity of proposed impoundment areas;
seasonal ranges,including denning areas,and movement
patterns of bears;and seasonal habitat use of black and
brown bears.1I
In Phase I of these studies,emphasis has been placed on determination
of relative abundance and seasonal distribution of the two species in
the vicinity of proposed impoundments,and on collection of baseline
information on basic biology of impact-area bears in order to compare
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Susitna-area populations with populations elsewhere.With these kinds
of data available by completion of Phase I,Phase II efforts can
concentrate on quantification of the levels of potential impacts and on
the reasons for them.
The objectives of the first year of effort were primari ly procedural
rather than analytical:to radio collar a sample of both black and
brown bears,to periodically locate these bears and pinpoint their
locations,to locate den sites of radio-collared bears,to begin
development of techniques which would permit an analysis of habitat
selectivity by bears,and to begin the collection of baseline
biological data by which to characterize impact-area bear populations.
1;3 -Caribou Herd Identity,Migration Patterns and Habitat Use:
Kenneth Pitcher
The Nelchina caribou (Rangifer tarandus)herd,one of 22 herds in
Alaska (Davis 1978),has been important to sport and subsistence
hunters because of its size and proximity to population centers in
southcentral Alaska.Between 1954 and 1980 over 100,000 caribou were
killed by hunters (Skoog 1968;unpublished data Alaska Department of
Fi sh and Game).
Because of its importance and accessibility,the Nelchina herd has been
the most intensively studied caribou herd in Alaska (Doerr 1978).The
U.S.Fish and Wildlife Service initiated research in 1948 and continued
through 1959 under the direction of Chatelain,Scott and Skoog (Skoog
1968).The Alaska Department of Fish and Game has been continually
involved with the Nelchina herd since statehood including intensive
research on population,harvest,distribution,disease and range
monitoring (Skoog 1968,Lentfer 1965,McGowan 1966,Glenn 1967,Hemming
and Glenn 1968,1969,Pegau and Hemming 1972,Neiland 1972,Pegau and
Bos 1972,Pegau et al.1973,Bos 1973,1974,Alaska Department of Fish
5
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and Game SU1~vey and Inventory Reports 1970-1980).Skoog IS (1968)
doctoral dissertation,a major work on caribou biology,deals largely
with the Nelchina herd.
There is currently under study a proposal to construct a large
hydroelectric project on the Susitna River in the western portion of
the Nelchina.caribou range.Impacts of the development,which may
include two dams and impoundments,access roads and electrical
transmission lines,on the Nelchina herd are unclear.Habitat loss due
to inundation does not appear to be a serious conside~ation as <1%of
the total Nelchina range would be involved.Skoog (1968)concluded
that caribou usage of this area was largely limited to transient
animals,although they occasionally spend time in the area in spring
using snow free areas.The proposed Watana impoundment could serve as
a barrier to migrating caribou.The area along the Susitna River
between Deadman Creek and Jay Creek has served as a traditional
migration route both during spring migration and the post-calving shift
(Hemming 1971).Ice shelving along the edges of the reservoir has been
suggested as a potential source of mortality to migrating caribou
(Hanscom and Osterkamp 1980).Roads,railroads and electrical
transmission lines have all been reported to disrupt caribou movements
(Klein 1971,Vilmo 1975,Cameron et al.1979).Disturbance associated
with construction and maintenance of the hydroelectric facilities could
result in a reduction of caribou use of nearby areas as shown for the
Prudhoe Bay oil fields (Cameron et al.1978).Proximity of the
traditional calving grounds to the Watana impoundment is of some
concern because of the importance of the area to the Nelchina herd and
increased human activity in the area implicit to development.
Suspected II su bherds"in the general area of the proposed impoundment
could become more isolated by development of the Susitna Hydroelectric
Project depending on their movement patterns and routes and their
reactions to the impoundments and related developments.
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Overall objectives of this project are to evaluate the potential
impacts of proposed Susitna hydroelectric development on the Nelchina
caribou herd and to suggest~ossible mitigating actions.Spe~ific
objectives jinclude:(1)determination of movement patterns,migration
routes and timing of major movements with emphasis on activities
occurring in the vicinity of proposed development;(2)delineation of
subherds (based on separate calving areas);(3)estimation of numbers
and sex and age of the main Nelchina herd and suspected subherds;and
(4)determination of habitat utilization of Nelchina caribou.
Complicating the interpretation of data gathered during short-term
studies of caribou migratory routes is the well recognized tendency for
changes in use of winter and surrmer ranges (Skoog 1968).The analysis
of data resulting from this study will have to rely heavily on
historical information.It is fortunate that results of intensive
research by Skoog.(1968)and others on the Nelchina caribou herd are
available and they will be used extensively in the analysis.
1.4 -Dall Sheep:Robert Tobey
Dall sheep (avis dall i)are known to occupy all portions of the upper
Susitna River basin which contain extensive areas of habitat above 4000
feet elevation (Alaska Dept.of Fish and Game 1973).Three such areas
1 ie close enough to proposed Susitna Hydroelectric Project impoundment
areas that sheep using these areas may be impacted by the project.
These areas are the Portage-Tsusena Creek drainages,the Watana Creek
Hills (east of Watana Creek)and Mount Watana including the hills to
the-southwest.
Because Dall sheep usually are found at elevations above 3000 feet,the
most likely adverse impact of the Susitna Hydroelectric Project
appeared to be disturbance from construction activities and access
roads.As a result the scope of this study was limited to a
determination of the seasonal distribution and abundance of sheep
adjacent to the proposed impoundments.
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The study area includes all drainages flowing into the Susitna River
from Gold Creek to Kosina Creek on the south and to the Denali Highway
on the north.Survey efforts were confi ned to the three areas of known
or suspected Dall sheep habitat within this area.
1.5 -Wolverine:Craig Gardner,Warren Ballard,and Donald Cornelius
The only information available on wolverine in the Susitna River basin
comes from work conducted by Rausch and Pearson (1972)and ADF&G
harvest records.Both sources provide a gross indication of population
status.The!se studies do not,however,provide the types of
information needed to determine the probable impacts of the proposed
Susitna Hydroelectric Project on wolverine populations.The current
study was initiated in April 1980 to:
(a)Determine distribution and abundance of the wolverine population
utilizing the study area.
(b)Determine wolverine seasonal habitat requirements and movement
patterns.
(c)Obtain an estimate of the population's age structure and sex ratio
to determine population trends.
(d)Determine the wolverine's dependency on the area which will be
inundated by the proposed dam system or deve loped through road or
transmission line construction.
This report addresses preliminary findings of wolverine movements and
home range size,habitat use,and distribution within the "impact area.
The report period only extends from 10 April through December 1980 due
to the late arrival of radio telemetry equipment.
8
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1.6 -Downstream Moose:Paul Arneson
The moose below the proposed impoundment and those above are
distinguished by the designations downstream and upstream and treated
separately in this study because the project would affect them in quite
different wclyS.
In the early 1950's,the Susitna valley was termed Ilprobably the most
productive moose habitat in the (Alaska)TerritoryJl (Chatel ai n 1951).
It was not until man-caused fires and clearing of land during and after
railroad construction created prime moose habitat that the moose
population rapidly increased.Prior to 1930 few moose were found in
the valley (Spencer and Chatel ain 1953).At that time moose 1ikely
utilized riparian habitats and what few browse species were available
in the mature spruce-hardwood forest.With the creation of new
habitat,the moose population expanded and presently remains at
relatively high levels.
The identities of moose populations that may use the Susitna River
during some stage of their life cycle have not been determined.Moose
in peripheral areas have been studied and do not appear to mix with
populations that are found in the Susitna valley from the Deskha River
on the south to Portage Creek on the north.An extensive collaring
project in the Matanuska valley in the 1ate 1960's revealed that most
moose remained in the valley.Only three were known to emigrate out of
the tagging area;one toMt.Yenlo and two to Mt.Susitna (Rausch
1971).However,only visual collars were used,and observations
normally occurred only on the wintering grounds.A radio and visual
collaring project was conducted in 1975~1977 in the Peters-Dutch Hills
area northwest of the Susitna River (Didrickson and Taylor 1978).No
marked moose were known to have moved eastward to the Susitna River.
9
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Therefore,the moose herd north of Willow to the proposed Devil Canyon
dam site is likely a discrete population although various
subpopu1ations likely exist within the overall population.The
greatest number of animals spend the rutting period on the western
foothills of the Talkeetna Mountains.Many remain in that vicinity
until deep snow covers their forage,and they must migrate to lower
elevations where riparian and disrupted habitats provide suitable
winter forage.
Because no surveys have been conducted in the past to determine winter
moose use of riparian habitats of the Susitna River,the only data we
can use as a indicator of moose presence on or near the ri ver are
records of rail road and highway ki 11 ed moose and document at ion of dead
moose on the river's islands during the severe winter of 1970-71.When
deep snows persist in the Willow to Talkeetna areas,the incidence of
railroad and highway-killed moose increases substantially.The most
recent example of this is in the winter of 1978-79 when at least 171
railroad-killed moose were documented after a moderately heavy snow
year.The fo 11 owi ng wi nter 1979-80 when much 1ess snow fe 11,far fewer
moose were recorded as railroad mortalities.During surveys in April
1971 following the severe winter of 1970-71,155 winter-killed moose
were tallied on the Susitna River and its tributaries.As stated by
LeResche et al.(1974),"During harsh winters,river 'bottoms l become
yarding areas for high densities of moose.When deep snow persists,
overbrowsing may occur,and these areas have been the scenes of the
most spectacular moose die-offs recorded in Alaska ...riparian
communities are the habitat of last resort for wintering moose."
Winter range is widely considered a limiting factor in the welfare of
moose and other ungulate populations.Because moose are dependent upon
secondary successional stages of vegetation for their winter forage,
their winter range must be periodically disrupted by fire,land
clearing,beaver activity or flooding in order to create the necessary
transitory stage of vegetation (Chatelain 1951).
10
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No research has been conducted to determine moose use of the important
riparian winter range along the Susitna River t and only a few studies
and quantitative records are available for that moose population in
general.Chatelain (1951 and 1952)and Spencer and Chatelain (1953)
reported on the early hi story and habitat use of moose in the Sus itna
valley.Rausch's (1959)research dealt with various parameters of
population dynamics of the moose herd in the Matanuska and Susitna
valleys.Bratlie (1968)furthersurrmarizes the status of the lower
Sus itna and Matanuska moose herds through 1967.LeResche (1974)
briefly summarized the status of the Susitna moose.Since that timet
the only information gathered concerning the welfare of the lower
Susitnamoose population has been the sex and age composition counts
conducted most every fall t harvest data and some age data from
railroad-killed moose.'
When planning began for downstream moose studies on the proposed
Susitna Hydr'oelectric Project t it was known that a paucity of
quantitative data was available for the area of greatest impact and
importance on the lower river.Therefore t basic research had to be
initiated to meet the most obvious objectives.As the project
continued t these objectives were periodically changed to meet changing
conditions such as weather t logistics and other factors.The primary
objectives of the study are:
(a)To determine the identity of moose subpopulations using the lower
Sus Hna .
(b)To determine seasonal distribution and movement patterns of these
moose subpopulations.
(c)To determine the relative magnitude of moose use of the lower
Sus itna.
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(d)To determine the relative use by moose of various habitats along
the lower Susitna and nearby areas.
(e)To summarize historic data as it pertains to the above
objectives.
Secondary objectives are:
(a)To determine food habits of moose using the lower Susitna versus
those using nearby areas.
(b)To determine the relative condition and productivity of the moose
herd of the lower Susitna and vicinity.
During the first year of study,4 of the 5 primary objectives have been
partially fulfilled.Primary objective (a)will be accomplished in
late winter if conditions permit.
1.7 -Upstream Moose:Warren Ballard,Donald Cornelius,and Craig
Gardner
Prior to statehood,management of Alaska's moose involved little more
than establishing liberal seasons,conducting sex and age composition
counts,monitoring harvests and controlling predators when necessary.
·Within the past two decades,however,Alaska1s human population has
grown significantly (Yankee 1974)and moose populations have been
declining.Consequently,management has become more intensive,
req-uiring detailed knowledge of various population and habitat
parameters which were not necessary when moose numbers were increasing
between 1940 and 1960 (Bishop and Rausch 1974).
Between 1963 and 1974,over 88,000 moose were harvested in Alaska
(ADF&G unpublished files).Of that number,18 percent were from the
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Nelchina basin (GMU-13).Moose numbers began to decline in the
Nelchina basin after the winter of 1961-62 (Bishop and Rausch 1974).
Deep snows were thought to be preventing the population from
recovering.McIlroy (1974)suggested that low bull :cow ratios had
influenced conception rates while Bishop and Rausch (1974)considered
habitat deficiencies to be at least partially responsible for these
dec 1ines.
Because of its depressed moose population and the importance of GMU-13
to the statewide harvest,a series of interrelated studies was
initiated in 1975 in an effort to identify problems and possible
solutions to aid in the population's recovery.These studies initially
focussed on moose-wolf relationships,to test the hypothesis that wolf
predation was responsible for low calf survival.A later study
involved removing wolves from a portion of GMU-13,then measuring
moose-calf survival in subsequent years.In order to evaluate the
effects of wolf removal on study moose herds,it was necessary to
accomplish the following:identify discrete moose populations and
calving areas,and determine pregnancy rates,age structure,and
physical condition of moose in these populations.During the early
phases of this study renewed interest in developing hydroelectric power
on the Susitna River prompted expansion of these moose studies to
include a preliminary assessment of the potential impacts of Susitna
River hydroelectr'ic development on moose.
1.8 -Wolf Studies:Warren Ballard,Robert Stephenson,and Ted
Spraker
Rausch (1969),Bishop and Rausch (1974)and McIlroy (1974)have
described the history of the GMU-13 moose population.All pointed to
an apparent inverse relationship between numbers of predators and
numbers of ungulates.Moose apparently began declining after the
severe winter of 1961-62.This decline continued and was hastened by
severe winters occurring in 1965-66,1970-71,and 1971-72.Fall calf:
cow ratios declined sharply and reached a record low for the basin in
13
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1975.Although wolf pred at i on was not suggested as the mai n reason for
the population decline,it was thought to have at least amplified the
decline and,more importantly,prevented recovery during mild winters
(Rausch et al.1975).This concern coupled with the findings of
Stephenson and Johnson (1972,1973),which revealed a high percentage
of calf moose in wolf scats,suggested that wolf predation on calves
was preventing the moose population from increasing.Consequently a
series of studies was initiated to obtain information on wolves,and on
wolf-moose relationships in the Nelchina basin (Stephenson 1978,
Ballard and Spraker 1979).The current study consists of a
continuation of these,with the additional objective of assessing the
probable impact of the proposed Susitna hydropower complex on wolves
and their prey.
14
2 -METHODOLOGY
Since the basic task for 1980,for each of the large mammals found in
the Susitna basin,has been to make estimates of distribution and
habitat selectivity,there is much in common among them with regard to
data records and analysis.Before field work is undertaken it is well
to have a plan for the systematic quantification and coding of data,
with the ultimate purposes of data processing in mind.Therefore,in
this,and each subsequent section,data processing shall come first.
In addition to the topics of distribution and habitat selectivity,data
processing includes species interaction analysis and basic data
processing and analysis,both included here.
2.1 -Data Processing
2.1.1 -Animal Distribution Analyses
Radio-telemetry techniques are being used by all the principal
investigators.The large numbers of animals fitted with radio
collars and the numbers of observations per animal dictate that
automated means be used for data analysis and display.The
cartographic nature of radio telemetry data creates speci al
problems in data processing which require use of specialized
computer resources.
2.1.2 -Habitat Selectivity Analyses
An important component in evaluation of the potential impacts of
dam construction is understanding how the various species utilize
the landscape available to them.The radio telemetry data are
used to identify where animals are located and,in some cases,
the activities in which the animals are engaged at that spot.
However,in order to identify those elements of the landscape
15
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which influence animal distributions and movements,it is
necessary to relate those observations to the total landscape
available to each animal.Several conceptual and technical
prob 1ems are assoc i ated with such anal yses.
2.1.3 -Species Interaction Analyses
The direct impacts of the proposed hydroelectric project will
undoubtedly vary among the big game species.However,close
ecological relationships between species (e.g.predator-prey
interactions)can result in indirect impacts which may not be
immediately apparent with single-species analyses.The
complexities of such analyses require the use of systems analysis
techniques and specialized computer resources.
2.1.4 -Basic Data Processing and Analysis
Direct assistance to principal investigators in data processing
and analysis is provided in the form of sampling designs,data
collection and analysis techniques,statistical analyses and
computer software.
2.2 -Area of Study
Because of differences in species distribution and range of movement,
and because of a project distinction between the impoundment region and
the downstream region,there are differences among the different
species with respect to the specific part of the landscape within which
its study took place.These differences are described by study,
below.
16
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2.2.1 -Black and Brown Bears
Captured bears were located along the Susitna River and its
tributaries between Devil Creek (T32N/R8W,Talkeetna Mts.Quad)
and the Vee site or gaging station (T30N/RI0E,Talkeetna Mts.
Quad).
The most di stant bear captured south of the Sus itna River was
G293 (upper Tsisi Creek),25 km south of the Susitna River.The
most distant bear captured north of the Susitna River was G312
(T21S/R4W,Healy Quad),about 30 km north of the Susitna River.
All black bears and half of the brown bears were captured within
5 kill of the Susitna River.
Based on movements of radio-collared bears,the study area was
expanded to include upper Chunilna Creek,the whole of Prairie
Creek,the height of land separating upper Susitna drainages 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.The total area encompassed by
movements of radio-collared brown bears included approximately
3,500 km 2 .Because of the difficulty of radio-monitoring
this large area,most monitoring efforts were concentrated on a
core area within 15 km either side of the main Susitna River,
encompassing an area of only 800 km 2 .Bears ranging outside
of this core area were radio-located less frequently than bears
with a greater portion of their home ranges within the core area.
Within 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 (T32N/R4-5W).The
most upstream radio-collared black bear was in the vicinity of
the Vee gaging station.
17
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2.2.2 -Caribou
The Nelchina herd occupies an area of approximately 20,000
mi 2 bounded by four mountain ranges:the Al aska Range to the
north,the Wrangell Mountains on the east,the Chugach Mountains
to the south and the Talkeetna Mountains to the west (Hemming
1971).
The Nelchina Range contains a diverse variety of habitats ranging
from spruce-covered lowlands to steep,barren mountains.Human
development is largely limited to the peripheries of the Nelchina
range and consists primarily of the Alaska Railroad,Parks
Highway,Denali Highway,Richardson Highway,Trans-Alaskan
Pipeline and Glenn Highway.
2.2.3 -Dall Sheep
Dall sheep occupy three areas within the study region which
contain extensive areas of habitat above 4,000 feet in elevation:
thePortage-Tsusena Creek drainages;the Watana Creek Hills (east
of Watana Creek);and MountWatana,inclUding the hills tcr the
southwest.
2.2.4 -Wolverine
The study area boundary follows the Susitna basin boundary in the
west to its intersection with the Denali Highway on the north,
the Denali Highway to its intersection with the Susitna River on .
the east,down the Susitna River to its confluence with the Tyone
River to Tyone Lake,then a southwest line to the confluence of
the Little Oshetna River with the Oshetna River and along the
Oshetna River to its intersection with the basin boundary on the
south.
18
2.2.5 -Downstream Moose
In the broadest sense,the study area was defined as the
floodplain of the Susitna River below the proposed Devil Canyon
dam,and those areas incl uded in the home range of moose
radio-collared on the Susitna River.In a practical,sense,the
study area was reduced to that portion of the Susitna River from
approximately Portage Creek south to the Delta Islands.This
portion of river was further subdivided into three physiographic
sections:'I)From Portage Creek to the confluence of the Susitna
and Chulitna rivers near Talkeetna,2)From Talkeetna to the
mouth of Montana Creek,and 3)From the mouth of Montana Creek to
the southern end of Delta Islands.In addition,a specific study
site consisting of several islands was selected near the mouth of
Goose Creek and the north end of Sheep Creek Slough.
2.2.6 -Upstream Moose
Moose movements and habitat use were studied in the upper Susitna
River basin upstream from Devil Mountain.Studies in relation to
hydroelectric development focused on the immediate hillsides
north of the river between Devil Mountain and the mouth of the
Mac 1aren River.
2.2.7 -Wolves
Wolves were studied most intensively in the Susitna River study
area,which has the following boundaries:the area is bordered
on the north by the Denali Highway and extends from the Maclaren
River at the Denal i Highway south to Tyone Lake and Lake Louise,
then to the Glenn Highway.The western boundary is generally
defined as northwest from the Little Nelchina River along the
upper elevations of the Talkeetna Mountains to near the mouth of
Portage Creek and then northeast to the Denali Highway.
19
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2.3 -Radio-telemetry
2.3.1 -Black and Brown Bears
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 by darts fired from a helicopter (Bell 206B).
.Drugs utilized included phencyclidine hydrochloride (Sernylan),
etorphine (M99)and its antagonist diprenorphine (M50-50),
ketamine hydrochloride (Vetelar),and xylazine (Rompun).
Standard morphological measurements were taken of immobil fzed
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 all bears
included:lip tattoos,ear tags,and ear flags.Individual bear
numbers referred to in the report represent tattoo numbers with a
uGu for brown bear and a uB u 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.Ten bears were fitted with double transmitter collars
designed so that one transmitter transmitted data on ambient
temperature.
Because of the late arrival of new bear collars,some individuals
were fitted with radio-collars designed for other species or used
bear radios from other projects.Except for the double-
transmitter bear radios,all new bear radios were designed with
mortality sensors which halve the pulse rate when the collar is
stationary for 2 hours,a change recognizable when a collar has
been shed or the bear is dead;it also prolongs battery life by
reduced electrical draw when bears are in dens.
20
"..,,,
Bears were captured on 10-22 April,1-7 May and 18-19 August,
1980.In the first effort only brown bears were seen.Beginning
on May 1 black bears were abundant,hav i ng emerged from thei r
dens apparently between 22 April and 1 May.The August tagging
effort was designed to capture black bears in mid-summer
habitats,away from their 1979-80 dens.These summer captures
avoided den-site selectivity biases which may have resulted had
only spring-captured bears been followed to their 1980-81 dens.
Attempts to locate radio-collared animals were made on
approximate 10 day intervals in 1980.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 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 9,18,and 27 October.Additional radio-locations
were made in conjunction with flights to locate other species in
the Susitna 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,
associations,topography,etc.were recorded.
Data collected on monitoring flights were transferred to
individual-specific data forms and maps which will be the basis
for keypunching and digitizing.
Habitat-type information recorded during monitoring flights was
restricted to the following broad categories identifiable from
the ai r:
21
......
I.Sparse tall spruce 10.Riparian willow
2.Mod.ta11 spruce II.Up 1and wi 11 ow
3.Dense tall spruce (riparian)12.Wi 11 ow bi rch
4.Sparse med.spruce 13.Aspen
5.Mod.med.spruce 14.Riparian hardwood
6.Dense med.spruce 15.Marsh
7.Sparse low spruce 16.Alder
8.Mod.low spruce 17.Rock/ice
9.Dense low spruce
The nine habitat types which include spruce were broken down into
categories reflecting relative densities and heights of the
spruce component.Procedures to determine habitat selectivity
from these data and/or data from vegetational mapping subtasks
are under development.
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 Stoneburg and Jonkel (1966)
and Johnson and Lucier (1975).Feces collected during capture
are stored for food habits studies (anticipated for Phase II).
Captured bears were photographed.
2.3.2 -Caribou
Data on movement patterns,migration routes,timing of major
movements,subherd status and habitat use were collected by
periodic relocations of radio-collared animals.Caribou were
captured by use of immobilizing drugs [etorphine (M-99)and
xylazine (Rompun)]administered with projectile syringes
(Cap-Chur equipment)shot from a helicopter.Radio-collars in
the 152.0-153.0 MHz range,purchased from Telonics Inc.,were
used.Radio-collared caribou were relocated from a fixed-wing
aircraft (Cessna 180 or PA-18-150)equipped with two Vagi
22
antennas,one attached to wing struts on each side of the
aircraft.Antenna leads were attached to a right/left switch box
coupled to a radio-tracing receiver/scanner.Animals were
located by balancing the transmitter signal between the two
antennas through use of the left/right switch and orientation of
the aircraft and following the signal.Forty-one caribou were
radio-collared.However,as of 10 December,12 collars had
either been shed or the animals had died leaving 29 functioning
transmitters on four males and 25 females.These included three
animals in the upper Susitna area,two in the Talkeetna River
area,and 24 in the main Nelchina herd.
2.3.3 -Dall Sheep
Dall sheep have not been subject to radio-telemetry to date,
because their principal habitat is well removed from the
impoundment area.
2.3.4 -Wolverine
Capture efforts were conducted during April and May 1980,using
helicopter capture techniques (Ballard and Spraker 1979).A
combination of 0.25 cc Sernylan (Bioceutic Lab.,Inc.)and 0.20
cc Rompun (Barrett Division of Cutter Laboratories,Inc.)was
used for immobilizing two wolverine.Because Sernylan is no
longer commercially available,a combination of 0.4 cc etorphine
(1 -mg/cc M-99,D-MPharmaceuticals,Inc.)and 0.5 cc Rompun was
used to capture the last three wolverine.Each captured
wolverine was aged,sexed,weighed,measured,ear tagged and
radio-collared.·Data from each wolverine were recorded on a
tagging form.After processing,wolverine immobilized with M-99
were injected with an equivalent cc dosage of the antagonist
dipremorphine (2 mg/ml M 50-50,D-M Pharmaceuticals,Inc.).Each
captured or necropsied wolverine is referred to by the last three
digits of its assigned accession number.
23
Radio collars (Telonics,Mesa,AZ)were constructed of butyl
rubber and had an inner circumference ranging from 29 to 39 cm.
Each collar was equipped with a whip antenna which extended 26 cm
from the collar.The entire unit weighed 232 g.
Radio locations were made approximately twice per week during
April and once per week thereafter,similar to methods described
by Mech (1974).Radio locations were recorded on a 1:63,360
U.S.G.S.map and activity,number of associates,and general
habitat were described on a standard field form.
Aerial habitat classification followed a system described by
Ballard and Taylor (1980).This system was specially designed to
describe habitat from fixed-wing aircraft.For this reason and
because we were more famil ar with it,it was used in 1i eu of
Viereck's and DyrnessJsclassification system (1980).We believe
that most of our cl assifications can be transformed to Viereck's
and Dyrness's level 3 classification,which is probably as
accurate as can be obtained from the air.
Wo 1ver i ne tracks were followed on the ground duri ng May and
December 1980 in an effort to gather information pertaining to
food habits and activity patterns.Tracks were initially found
by aircraft.Tracks were then followed on snowshoes for 1 to 2
days.
Wol veri ne carcasses were purchased from hunters and trappers in
Game Management Unit (GMU)13 by offering $10.00 per carcass.
Each carcass was necropsied in an effort to quantify age
structure of the harvest,reproductive status,and morphometric·
measurements.
Wolverine observation forms were distributed to pilots,
biologists and other investigators in the study area in an
attempt to gather more data on wolverine distribution.Sightings
24
.-
of both wolverine and wolverine tracks,general description of
habitat and act ivity were soli cited.Harvest records from
seal ing forms and bounty records from 1962 to present were
examined.
2.3.5 -Downstream Moose
The study began in April 1980 when 10 moose were captured:three
in the upper section (1 bull,2 cows)north of Curry,three in
the middle section (2 bulls,1 cow)plus one cow was collared at
the middle-lower section boundary,and three in the lower section
(1 bull,2 cows)near the mouth of Sheep Creek.All were darted
from a helicopter using 9 cc M-99 and 1 cc Rompun.Besides
placing a radio/visual collar on each moose,orange ear-flagging
and metal tags were placed in both ears.Blood,hair,a tooth
and feces were collected from each moose,various morphometric
measurements were made and each cow was palpated to determine
pregnancy status.When given the antagonist M50-50 each moose
recovered in a normal amount of time,and no mortal ities occurred
in the tagging operation.
Re 1ocat i on fl i ghts of the radi o-co 11 aredmoose began 29 April
1980.Aircraft for these flights were:Cessna 172 and 180 and
PA 18~150.Flights were conducted at approximately 10-day
interva 1s duri ng summer and fall and at 15-or-more-day i nterva 1s
in winter when moose were not making long movements between
relocations.At each radio-relocation of a collared moose the
following parameters were recorded:date,time,location,visual
relocation,antlers present,activity,number of young,
association with other moose with a sex and age breakdown,
habitat type,elevation,slope,aspect,weather conditions
including snow cover and whether a photograph was taken.
25
After each flight the animal locations were plotted on 1·:63,360
USGS quad maps,and the data were organized on keypunch forms.
Later,location data will be digitized on a geoproces.sor to
facilitate analysis.Other data from each observation of
radio-collared moose will be computeri zed at a later date.
2.3.6 -Upstream Moose
Adult moose were captured with the aid ofa helicopter by darting
with lO-cc al um"j num darts fi red from a CAP-CHUR gun with
appropriate dosages of M~99 and Rompun.Helicopter capture
methods were identical to those used previously on other Alaskan
moose movement studi es (Ni el son and Shaw 1967).No attempt was
made to capture yearling moose.
Captured moose were marked either with a radio collar,a colored,
numbered visual collar,or both,permitting individual
recogni ti on from fixed-wing ai rcraft.One-half of the radi 0-
collars were color-coded with canvas tape wrapped around the
machine belting.Visual collars were similar to those described
by Franzmann et al.(1974).Radio collars were constructed of
machine belting 1.3 cm thick by 5.4 cm wide.Collars had an
inner adjustable circumference ranging from 101 cm to 111 cm.
The belting surrounded the radio components which were encased in
dental acrylic,theoretically making the unit waterproof.The
entire unit weighed 1,113 grams.Radio frequencies were in the
150.0 MHz range.Radio collars were purchased from A.V.M.
Instrument Company (810 Denni son Dri ve,Champai gn,Ill.)and
visual collars were obtained from Denver Tent and Awning Co.
(Denver,Co 1o.).
Each moose was also ear-tagged with a numbered Monel metal tag,
fixed to the base of the ear.Most metal tags were accompanied
by a 5 cm x 13 cm piece of colored plastic.
26
."'"
Radio signals were received ~ith a 4-band,48-channel portable
receiver purchased from A.V.M.Instrument Co.Radio-collared
moose were relocated from a Piper PA-18 Super Cub and STOL Cessna
180 fixed-wing aircraft.Tracking methods and equipment used
were similar to those described by Mech (1974).
2.3.7 -Wolves
Wolves were captured for radio-telemetry studies with a CAP-CHUR
gun and dart fired from a Jet Ranger 206B helicopter using
methods similar to those described by Baer et al.(1978).Our
capture technique differed from theirs in that we darted in all
types of vegetative cover and while the animal was moving.
Captured wolves were equipped initially with an adjustable
machine belt radio collar manufactured by AVM Instrument Co.,and
later with an adjustable collar made of fiberglass and urethane
manufactured by Telonics (Mesa,Ariz.).
Wolves were relocated with a portable radio-telemetry receiver
manufactured by AVM Instrument Co.The receiver contained four
bands with 12 channels per band and covered frequencies in the
150.0 to 152.0 MHz range.
2.4 -Population Studies
2.4.1 -Black and Brown Bears
Determination of the number of bears in the Susitna study area
was defined as a major objective of the impact assessment study.
Bear population estimates are exceptionally difficult and
expensive to obtain and it is unlikely that an accurate estimate
wi 11 be achi eved with the funds avail ab 1e for Phase I bear
studies.An imprecise estimate may be obtainable from radio-
27
-
tracking determinations of home range size coupled with an
estimate of the proportion of the population 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 Susitna
study area and because of the large home range sizes of Nelchina
brown bears (average=57o km 2 ,range=191-1,38o km 2 ,Miller
and Ballard 1980),it will be expensive to obtain a precise
estimate.
2.4.2 -Caribou
A modified version of the aerial photo-direct count-extrapolation
census procedure (Hemming and Glenn 1969,Davis et al.1979,
Doerr 1979)was used to estimate the size of the Nelchina herd.
This technique is composed of three separate procedures:(1)a
complete count of all animals in the post-calving aggregation;
(2)a compos iti on count of these same animal s to determine the
proportion of adult females;and (3)representative fall
composition sampling of the entire herd to determine the
proportions of females,males and calves (Doerr 1979).
Acceptance of four assumptions is necessary for the APDCE
technique:(1)all females in the herd are present in the
post-calving aggregatioris;(2)adult females are randomly
distributed throughout the post-calving aggregations;(3)the sex
and age cohorts are randomly distributed throughout the herd
during fall;and (4)mortality of adult females from the time of
post-calving aggregation to the fall composition counts is zero
(Davis et al.1979).An evaluation of these assumptions by Davis
et al.(1979)indicated that all but assumption #3 were valid and
that the collection of representative fall composition data was
the most difficult procedure.
28
,''''''
The fall population estimate is calculated from the following
equation (Doerr 1979).
FP =Na x Pf x Sf x(1 +R)
where:
FP =estimated fall population;
Na =number of animals in the post-calving aggregation;
Pf =proportion of females in post-calving agregation;
Sf =survival of females from the time of post-calving
counts until the fall;and
R =ratio of caribou other than females to females in the
fall.
Reconnaissance fl ights were made in a C-180 to determine when
caribou were suitably aggregated to census.PA-18-150 Super Cubs
are used to survey the aggregations and the caribou herds were
either photographed or directly counted.Hand-held,motor
driven,35 mm cameras were used to photograph caribou groups.
The 35 mm color slides of caribou groups were projected on a
paper screen and caribou images marked.The number of images
were then counted.
A helicopter (Bell 206B)was used to sample the post-calving
aggregations and the herd during the breeding season to estimate
proportions of females,males,and calves.Groups of caribou
were approached from the rear until the sex of each animal older
than calves could be determined from the external genitalia
(presence or absence of the vulva).
2.4.3 -Dall Sheep
Sheep observations were solicited from all Susitna study
participan~s.Date,location,number,sex and age of all sheep
29
,....
observed and subsequently reported were recorded on 1 :63,360 USGS
topographic maps.Winter and spring observations were especially
requested because they show seasonal distribution and.,in some
instances,habitat use.
An aerial survey was conducted with a PA-18 Super Cub on 22 and
23 July 1980 in an effort to determine sex-age composition and
summer distribution.Sixteen hours were spent surveying sheep.
All observed sheep were identified as to number,sex~and age
class.Locations were plotted on 1:63,360 USGS maps.Methods
used during the survey were typical of those used to survey sheep
elsewhere in Alaska (McKnight and Hinman 1980).
2.4.4 -Wolverine
Data obtained during this study period are not sufficient for
population analysis,but it is anticipated that preliminary
popu 1at ion est i mat es wi 11 be avail ab 1e after anoth er year of
study.
2.4.5 -Downstream Moose
Data obtained during this study period were not sufficient for
population analysis,but it is anticipated that preliminary
population estimates will be available after another year of
study.
2.4.6 -Upstream Moose
From 25 May through 13 June 1980,eight flights were made to
determine the birth rate and calving area of radio-collared moose
in the study area.
30
-Teeth obtained from radio-collared moose were aged during the
report period;in addition,teeth from wolf-killed moose in the
study area were aged and bone marrow samples were analyzed to
determine relative condition of moose preyed upon by wolves.
Duri ng August,1980,33 snow depth markers were install ed along
eight transects in moose habitat throughout the study area.
These markers were read throughout the winter to determine the
relationship between moose movements and snow depth.The markers
were placed in areas used by moose during the March 1980 winter
distribution survey and preliminary Susitna studies.Specific
site selection was done in collaboration with Jeff Kaufman from
R&M Consultants and George Calgett of the U.S Soil Conservation
Service.Random stratified moose census counts were designed
with the assistance of Dr.Wm.Gasaway,and Carried out in late
October and early November,1980.
2.4.7 -Wolves
Through radiolocation and aerial observation wolf packs were
identified and their seasonal ranges and composition determined.
2.5 -Food Availability and Use
This aspect of the study focussed on the food of moose particularly.
Moose make much winter use of successional riparian shrubs and these
shrubs would tend to be flooded by an impoundment or affected by
changes in the seasonal magnitude of downstream flow.
31
2.5.1 -Downstream Moose
Techniques to be used in spring pellet group counts and browse
utilization/density studies were researched and several experts
in the field were contacted.Several designs were discussed,but
it was decided that each project is unique,and methods of this
type need to be "tailor-made"for the project.Therefore,
several methods were tried during spring 1980 to determine which
was best suited for the habitats involved and which were best
suited for the degree of moose use in the area.Areas determined
to have the greatest variance in 1980 will be sampled with
greater intensity in spring 1981.
In the initial survey of the river,transect lines were randomly
selected in the upper,mid and lower portions of each of the
three sections.Transects followed existing section lines.On
these transects the number of br'ows~plants available to moose
(or hare and beaver)were recorded on a strip 1 meter wide along
the entire transect,but the transect was divided into 10-meter
sections.Pellet groups were counted in a 2-meter width in each
of the 10-meter sect ions.The habitat type in each 10-meter
section was also recorded.Only the first 100-meters of upland
habitat on opposite banks of the river were surveyed at each
transect.
For the second portion of the study,one study site was selected
near the mouth of Sheep Creek.Ten transects were randomly
selected on the study area.Along each transect a 2 X 2 meter
plot was used every 20 meters to record the browse
availability/utilization.At the same location a 2-meter r,adius
circle was used for pellet groups.The smaller plot size was
chosen to better fit within given habitat types.
32
Five browse species were considered:willow (Salix sp),
cottonwood (Populus balsamifera),paper birch (Betula
papyrifera),highbush cranberry (Viburnum edule)and rose (Rosa
acicularis).They were considered "browsable Jl if they were over
40 cm tall (i.e.available above or near the snowline in winter)
and if their circumference at breast height was 13 cm or less
(this circumference has been determined to be the maximum that
can be broken over by moose while foraging).To be counted asa
separate stem from a cl uster of stems,the pl ant must have been
surrounded by soi 1 or if it was a "sucker"on a cut-off stump or
mature tree it must have been at an angle of 45 degrees or less
from the main stem of the plant.If it was between 45 degrees
and perpendicular (90 degrees)to the trunk,it was classified as
a branch and not a browse stem.
Only pellet groups containing 12 or more moose droppings and with
their approximate geometric center within the transect were
counted.
The habitat classification followed Viereck and Dyrness (1980)as
closely as possible.Additionally,the density and height of
plants were recorded.Four density categories were used:1)
Open (10%or less crown canopy cover),2)Sparse (10-25%),3)
Medium (25-60%)and 4)Closed (60-100%).Four height categories
were also used:1)Low (1.5 m or less),2)Medium (1.5-6.0 m
[considered prime moose browse]),3)Tall (6.0-9.0 tall,5.0-13
cm dbh)and 4)Climax (9.0 m or more high,13 cm or more dbh).
33
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I'"''
3 -RESULTS AND DISCUSSION
3.1 -Data Processing
In the first year of Phase I studies the biometrics and data processing
efforts have concentrated on development of techniques and procedures
designed to meet the objectives outlined previously.Delays in
obtaining personnel and access to needed computer resources have
resulted in little actual analysis being accomplished in the first
year,but substantial progress has been made in development,and many
kinds of analyses appear ready to begin early in the second year of
Phase I studies.The following is a brief discussion of these
techniques and procedures.
3.1.1 -Data Entry of Radio Telemetry Observations
Each time a marked animal is relocated the observer pinpoints the
location on a map and records pertinent descriptive information
(identity,behavior,associations,habitat,environmental
factors,etc.)on a fi e 1d form.
The types of descriptive information recorded vary among species.
In order to facilitate analysis,the cartographic information
about the location of the animal must be associated with the
descriptive information.This process required handling the two
types of information separately for data entry and conversion,
and subsequently merging them for data analysis.
Descriptive data are transcribed onto standardized forms by the
investigators.These data are subsequently key-punched and
entered on the IBM computer at the Department of Administration,
Division of Data Processing,Anchorage.A magnetic tape of these
data is created and the information transferred to the Department
of Natural Resource's geoprocessing center for analysis.
34
-
/'..,
-
Cartographic information is converted to digital,x-y coordinates
through the process of digitization.This involves placing a map
on a digitizing table which,with the use of an electronic
tracing tool known as a cursor,records the two-dimensional
coordinates of a given location relative to known reference
points.Defining the reference points requires registration of
each map each time it is placed on the digitizing table.To
avoid having to register the same map for every individual animal
with sightings on that map,points of sightings are transferred
from maps used in the field to mylar overlays,one for each
animal for every ~ase map on which it has been sighted.
Digitization is done from these mylar overlays at the Department
of Natural Resource's geoprocessing center,with registration of
each base map required only once for each corresponding set of
overlays.
The cartographic information from digitization is then combined
with the descriptive information in a master file.This master
file is continually updated as new information is gathered.A
back up copy of the master file is created after each update.
3.1.2 -Data Analysis of Location Information
The Department of Natural Resources'geoprocessor was especially
designed for automated analysis and display of geographic-based
information.The geoprocessor is a mini computer with an array
of associated peripheral devices such as a tape drive,disk unit,
digitizer,lineprinter,computer terminals and an x-y drum
plotter for drawing high quality color graphic displays on paper
or mylar.The system includes a versatile set of computer
programs (software)for performing functions on map-based
information.These functions include calculating polygon-line
interactions,polygon-polygon intersections,unions and relative
differences,scale conversions,directions and distances between
35
:~
-.~
points and areas.Additional programs are available to perform
functions on descriptive data such as sorting,selecting subsets,
report writing,and mathematical calculations.User~specific
software can also be written and integrated into the system.
Before committing the big game studies to utilization of the
geoprocessor for data analysis,a pilot project was undertaken.
This was intended to provide project personnel with the
opportunity to gain a better understanding of its capabilities
and limitations,and to iron out potential technical difficulties
prior to actual use on real information.The pilot project
consisted of creating a IId ummy llset of animal sightings and going
through the process of data entry and analysis.Three individual
animals,two moose and one wolf were created with 25 sightings
each.Descriptive data forms for each animal were created and
observation points mapped on two USGS 1:63,360 scale maps.In
developing the pilot project,several new computer programs had
to be developed to perform the task of.merging the cartographic
and descriptive files.These programs have been tested and the
system is now ready for the data entry process as previously
outlined.
Several major problems have yet to be solved,for example,means
of lumping observations in a meaningful fashion in order to
define home ranges or areas of use.In the pilot project,home
range polygons were defined by connecting the outermost points
with straight lines.The area of each polygon and the areas of
overlap can be determined by the geoprocessor.Other methods of
describing areas of use may ultimately prove to be more
meaningful,for example,ellipses encompassing a certain
percentage of point locations.
36
I'"''''
3.1.3.-Habitat Selectivity Analyses
The radio telemetry observations provide information on where
selected animals are at specific times~In order to utilize this
information to analyze habitat selectivity by the various species
several assumptions about these observations must be made,and
information about areas where animals are not located is
required.
The necessary assumptions are:
(a)The individuals which have been radio-collared represent a
random sample from the population.This assumption may be
violated if,during the capture process,certain individuals
or groups of individuals have different probabilities of
bei ng captured.Femal es with young,for example,may be
more secretive and less prone to capture in some species.
(b)The observations of an individual radio-collared animal
represent a random sample from the distribution of that
individual.All radio telemetry observations are made with
the use of aircraft.The locations of individuals during
times when the use of aircraft is not possible (e.g.
inclement weather,hours of darkness)may differ
substantially.
With these assumptions it is possible to compare areas which are
utilized with those areas which are not utilized.However,
several difficulties still remain.These include:
(a)Determining the total area available to an individual.This
is an obvious requirement for the basis of the comparison.
It makes little sense to compare areas which are not
available to be selected.
37
.-
(b)Accurately describing the landscape f~atures.The
particular components of the habitat which motivate
selection may not be obvious or easily quantifiable.They
may also vary with temporal conditions.
Two techniques for analyzing habitat selectivity are being
considered.The first involves expanding the use of the
geoprocessor to include landscape features.This would require
that the landscape attributes be spatially defined and entered
into the system via digitization.The level of resolution
required and the complexity of the attributes would determine the
level of effort necessary to accomplish this task.For example,
topographic features could be digitized from standard USGS maps.
However,capturing all the detail present in these maps would
require an excessive effort and create data processing problems
because of volume.Also,not all landscape features lend
themselves to precise spatial definitions.Vegetation,for
example,often occurs along continua.Aerial photos are being
used by the Agricultural Experimental Station to create
vegetation maps,but the vegetation types designated on the maps
are based on overstory vegetation.
While the geoprocessor is an effective tool to overlay animal
locations on landscape features,the degree of accuracy required
to provide meaningful results is often beyond the level of the
original maps.Extensive editing and integration of various maps
may be required.For example,when vegetation maps made from
aerial photos are electronically overlayed onto topographic maps,
boundaries around water bodies and other dominant features rarely
match up initially.Similarly,the ability of the observer
tracking radio-collared animals to accurately pinpoint the
location on a map can greatly influence the results.Likewise,
the description of the habitat recorded by the observer at the
time of sighting ~ay not coincide with that entered from
vegetation maps from aerial photos.Considering the problems
38
-
,~
,....,
associated with this technique for habitat selectivity analysis,
it was decided that this technique would be appl ied on a trial
basis only.Using the vegetation maps by the Agricultural
Experimental Station,landscape features for the area of
impoundment will be digitized.This technique will then be
evaluated before expanding into areas outside impoundments.
The second technique for habitat selectivity analyses arose from
consideration of the difficulties associated with the first
technique.The basic premise of the second technique is that the
most accurate information on the landscape features utilized by
the various species is obtained from the observer recording the
sighting.The process of transferring this information to maps
introduces additional error.The second technique avoids this
error by comparing landscape features at randomly selected points
with those where animals were observed.
The experimental design for the second technique is as follows.
The study area will be divided into sampling units based on
ecological factors.Sample units will vary in size and shape and
will be constructed such that it is reasonable to assume that the
entire sample unit is avail able to any individual animal located
in it.Once an animal observation has been made in a sample
unit,random points will be selected within the sample unit.
Observers will drop a marker from the aircraft at each random
location and record the same landscape information as is recorded
for animal sightings.The number of random locations selected
will depend on the homogeneity of the sample unit and required
accuracy.Standard statistical techniques will be used to
compare the random locations with the animal observations.
39
,0"'"
-
.-
3.1.4 -Species Interaction Analyses
Computer simulation modelling is an effective technique for
analyzing species interactions.The most cumbersome aspect of
simulation modelling is the computer program development.
Specialized computer software for simulation modelling is
commercially available.These software packages provide the user
with program flexibility,enhanced output capability in the form
of graphics,and streamlined input procedures which greatly
reduce the effort required for program development.However,the
majority of the commercial packages are aimed at economic and
business applications.It is,therefore,necessary to develop
our own simulation software package.Specifications for the
software are presently being developed.Several months of
program development and testing will be required to produce an
operational system.Once this system is in place,simulation
modelling of species interactions can proceed rapidly and
efficiently.
3.2 -Black and Brown Bears
3.2.1 -Sex and Age Composition of Captured Animals
Fifty-four bears were captured and marked in 1980,27 brown bears
(Table 1)and 27 black bears (Table 2).One black bear (B303)
was captured twice bringing the total number of black bear
captures to 28.One bear of each species died during capture
operations (B296 and G278).
Radio collars were placed on 15 brown bears and 11 of these
remain active.Four brown bears shed their collars (G279,G214,
G295,and G309),all of these were large males (average age =9.2
years,range 4-12).One non-radioed bear (G311)was shot by a
hunter.The total number of marked and radio-collared brown
40
-Table
Brown bears captured in the spring of 1980.
#Capture
Tattoo Sex Age Wt.Date Frequency Ear flags Comments
2.5:284 &285
101/2 ylgst not marked
Capture mortality
Collar shed by 6/12
Recollar next spring
Recaptured '78 bear-
collar shed 9/9
Not turgid
Turgid
101/2 @
101/283
101/283
Collar shed by 5/4
101/2 ylgs,turgid
101/299
101/299
Turgid
blue
orange
orange
orange
orange
orange
white
orange
orange
green
green
green
white
white
orange
orange
white
orange
orange
white
white
orange
.green
148.004
152.840
148.950
150.041/.103
150.142/.092
(150.061/.102)
150.041/.112
(150.368)
149.508
(151.512)
152.830
153.810
(150.650 )
152.860
4/10
4/19
4/20
4/20
4/22
4/22
4/22
4/22
4/22
4/22
5/1
5/2
5/2
5/2
5/3
5/4
5/4
5/4
5/4
5/6
5/6
5/6
5/7
5/7
Turgid(?)
Collar shed by 5/14
101/311
101/312,killed by
hunter 9/16
5/7 152.820 orange 101/314 @ 2.5
5/7 orange 101/313
5/7 green alone
250*
325*
280*
180*
91)*
180*
225;~
375*
400*
300*
300*
286
154
264
174
277
607
589
285
65
65
163
480
240
600
319
227
F 9.5
F 2.5
F 1.5
F 10.5
Ii 9.5
Ii 9.5
Ii 5.5
M 4.5
F 3.5
Ii 4.5
F 12.5
Ii 2.5
Ii 2.5
Ii 3.5
F 3.5
Ii 4.5
Ii 10.5
Ii 12.5
F 13.5
Ii 1.5
Ii 1.5
F 3.5
Ii 6.5
F 5.5
Ii 12.5
F 10.5
Ii (2.5)
313
314
315
281
282
283
284
285
286
292
293
294
(295)
299
297
298
306
308A
308B
(309)
312
(311)
277
(278)
(279)
280
(214)
-
....
.-
-
*Weight estimated ()Indicates shed collar or dead bear
___~__.-l
~
Table 2
1l1ack bears captured in the spring and summer of 1980 ..
Capture
""...-Tattoo Sex Age Wt.Date Frequency Ear flags Comments
fI'o1~287 M 10.5 225*5/1 150.111/.082 white
(288)F 10.5 125*5/1 (150.032/.122)white w/2 ylgs,turgid,
collar shed by 8/27/80
289 F 9.5 130*5/2 150.092/.062 white w/2 ylgs,turgid
290 F 8.5 103 5/2 150.022/.142 blue w/2 ylgs,turgid
(291)M (3.5)73 5/2 (150;030)orange Post-capture mortality
(296).M (l0.5)227 5/3 (--)Capture mortality
(300)M (7.5 )274 5/4 (150.023/.121)orange Post-capture mortality
301 F 7.5 .115 5/4-153.850 green w/1 ylg,turgid
,Iffl-(302)M 8.5 287 5/4 (I50.189)blue collar shed by 8/4/80
303 M 7.5 217 5/4.153.870.green
304 M 10.5 235 5/4 150.031/.080 orange
(305)M (9.5)217 5/5 (151.350)green Shot by hunter 8/30/80
307 M 2.5 105 5/5 .orange
310 M 2.5 .85 5/6 ~-blue/green
(316)F (12.5)150*5/7 (148.912)blue w/1 newborn,1 ylg.
shot by hunter 8/28/80
317 F 7.8 133 8/18 152.703 white
~318 F 5.8 126 8/18 152.690 -white w/1 cub
319 M 3.8 174 8/18 152.682 orange
(320)M (4.8)200*8/18 (152.663)orange Shot by hunter 9/9/80
321 .F 10.8 175*8/18 152.673 white
322 M 4.8 154 8/19 152.643 orange w/324-323 M 2';8 122 8/18 152.612 orange
324 M 5.8 190 8/19 152.624 orange w/322
325 F 11.8 164 8/18 152.632 white
(326)F (5.8)125 8/19 (152.560)white w/2 cubs,shot by
I""'"hunter on 8/28/80
327 .F 5.8 118 8/19 152.653 white w/2 cubs
-328 F 6.8 150 8/19 152.573 white w/303
303 M 7.8 260 8/19 152.870 orange recapture
*Weight estimated ( )Shed collar or dead bear
-
-
....,
bears remaining in the Susitna study area (October 1980)by sex
and age categories is shown in Table 3.
The sex and age composition of current radio-collared bears is
shown in Tables 3 and 4.The sex ratio of adult brown bears
captured for Susitna hydro studies is comparable to that in an
earlier study nearby and in the 10 year harvest statistics for
Unit 13 (Table 5).The age structure of hydro-project bears was
younger than in these other subpopulations (Table 5),most likely
the result of small sample size for hydro-project bears but
possibly indicating locally heavy harvest levels.
Larger numbers of radio-collared individuals would be helpful for
both species.This is especially the case for brown bears which
will be subject to heavy hunting pressures in spring 1981 if
weather conditions are good during the season.Given equivalent
hunting losses of radio-collared black bears in 1981,by the end
of Phase I studies active black bear radios will have been
reduced to minimally acceptable numbers.
3.2.2 -Brown Bear Seasonal Distribution and Movements
Relocations in 1980 for 15 radio-collared brown bears (excluding
I
offspring and sequenti al relocations at the same den site)total
120 points (Table 6).For the 11 bears with active radios in
winter 1980/81,107 relocations were obtained (3-14 per
individual)(Table 6).Dens were tentatively located for 10 of
these 11 bears.Sightings of unmarked brown bears totaled 23,
yielding a total of 143 point-locations for brown bears in 1980.
These point-locations are in the process of being digitized.The
digitization process is designed to facilitate mapping and
analysis of the point-location data;detailed analysis of these
data will be delayed until digitization is complete and until
43
Table 3.-
Sex and age composition of marked brown bears remalnlng in the
study area in October 1980.Number with radio-collars is given
in parentheses.
_.1980 Age Males Females
0-1 0 0....1-2 2 1
2-3 2**·1
3-4 1 3 (1 )
4-5 3 (1 )0
5-6 1 (1)1 (1)
6-7 1 (1 )0
7-8 0 0"..,
8-9 0 0
9-10 1 1 (1)
10-11 1 (1)*2 (2 )
#ill;l'il'o,11-12 0 0
12-13 2 1 (1)
13-14 0 1 (1)
fl'§9O:;
Totals 14 (4)11 (7)
***
One capture-related mortality not included (G214).
One bear shot by hunter not included (G311).
---------------------------_.._--_._.__.-
Table 4
Sex and age composition of marked
Susitna study area,October 1980.
given in parentheses.
black bears remalnlng in the
Number with radio-collars is
"'..
.-
1980 Age Males Females
O-~0 0
1-2 0 0
2-3 3 (1 )0
3-4 1 (1)*0
4-5 1 (1)**0
5-6 ~(1)2 (2)**
6-7 0 1 (1)
7-8 ~(~)*2 (2 )
8-9 1 1 (1)
9-10 0 **1 (1)
10-1I.2 (2)***2 (~)
11-12 0 1 .(1)
12-13 0 0 **
Totals 10 (7)10 (9)
*One post-capture mortality not included (B291,B300).
**One bear shot by hunter not included (B30S,B320,B326,B316).
***One capture-related mortality not included (B296).
Table 5
Average spring ages~in years~of Susitna area brown bear sub-'
populations~3.0 years or older.
......
"".,
Subpopulation
A*
B**
c***
A*
B**
c***
Average
Spring Age
in Years
~1a 1es
8.0
7.4
6.0
Females
7.7
7.4
6.6
{Range}
{3.5-23.5}
(3.5-21.5)
(3.5-12.5)
(3.5-28.5)
{3.5-16.5}
{3.5-13.5}
n
208
17
11
191
15
9
-
*Game Management Unit 13 fall harvests~1970-1980
**1979 Upper Susitna studies (Miller and Ballard 1980)
***1980 Susitna Hydro studies
Table 6
Brown bear relocation records for 1980.
1980
Brown age at Capture Date-Number of No.River 80/81 Den
fIIIll'llll Dear II Sex capture Last Location Relocations Crossings Located
277*F 10.5 4/10/80 -8/27/80 5 0 yes
(278)H 9.5 4/19/80 -0
(279)*M 9.-5 4/20/80 -<6/12/80 1 0
280*H 5.5 4/20/80 -10/13/80 9 2 yes
(214 )*M 4.5 4/22/80 -<9/980 10 0
281*F 3.5 4/22/80 -10/13/80 13 1 yes
282 11 4.5 4/22/80 -
283*F 12.5 4/22/80 -10/9/80 10 0 yes·
284**M 2.5 4/22/80 -.....285**11 2.5 4/22/80
286 H 3.5 5/1/80 --
292 F 3.5 5//280 -
293*M 4.5 5/2/80 -10/13/80 . 6 2 no
"294*H iO.5 5/2/80 -10/13/80 13 i yes?(295~*M 12.5 5/3/80 -<5/4/80 1 1
e"""i3.5 5/4/80.-10/13/80299F 10 2 yes
297**M 1.5 5/4/80 -
298**H 1.5 5/4/80 -,.....306 F :3.5 5/4/80 -0
30BA*M 6.5 5/6/80 -7/2/80 3 0
308B*F 5.5 5/6/80 -10/13/80 14 5 yes?
(309)*11.12.5 5/6/80 -<5/14/80 1 0
312 M 10.5 5/7/80 -9/29/80 11 0 yes
(311)**M 2.5 5/7/80 -
313*F 9.5 5/7/80 -10/13/80 13 0 yes
",...
314 **F 1.5 5/7/80 -
315 F 1.5 5/7/80 -
*Rad i a-co 11 a red
( )Indicates shed collar or dead bear.
**bears which are offspring of previously listed adults
.....
sufficient data to draw preliminary conclusions are available.
Only general hypotheses,based on the preliminary point-location
data,will be presented .
Brown bear use of the area in the immediate vicinity of the
Susitna River and proposed impoundments appeared to be greatest
in the early spring,4-6 weeks following emergence from dens.
Eleven of the 21 bears (offspring excluded)captured irt the
spring of 1980 were within about 5 km of the Susitna River and
most of these were on south-facing slopes from which the snow had
melted.Inspection of feces collected from these bears suggests
that many were feeding on berries (Vaccinium spp.)remaining from
the previous year's crop.At least two of these bears were
feedi ng on a moose carcass found on the bank of the Sus itna
River,this moose probably was a winter kill rather than a bear
kill.It is a reasonable speculation that bear scavenging early
in the spring would be concentrated in the moose winter range
along the river,the area where most carcasses would be found.
The steep south-facing slopes along the Susitna River are also
the first areas to become clear of snow and many offer the
earliest opportunity to forage for vegetable material (previous
year's berries,spring sedges and other new growth,tubers,
etc.).
Preliminary data suggest that many brown bears move to lowland
areas soon after emergence from dens.The 1980 capture locations
for seven of the nine bears followed to 1980/81 dens was lower
than the elevations of the 1980/81 dens.The average elevation
difference for these seven bears was 1,266 ft.(275-2,370 ft.)
(Tab 1e 7).
The importance of these spring foraging areas will be documented
early in the spring of 1981 by following bears as they,emerge
from their dens.If the same bears that were captured along the
48
.",,,,
Table 7
Capture and den site locations for brown bears captured in 1980.
Bear'USGS Coordinates-Number Quadrangle Township Range tieridan Elevation (feet)
Capture Sites
309 Talkeetna tits.31N 3&Seward 2350
30BB Talkeetna Mts.32N 3&Seward 3350
315 Talkeetna Mts.31N 3&Seward 3250
~~286 Talkeetna Mts.31N 4E Seward 1450
294 Talkeetna Mts.31N 4E Seward 1395
283 Talkeetna Mts.33N 4E Seward 3875
313 Talkeetna Mts.33N 4E Seward 3650
308A Talkeetna Mts.30N 5&Seward 3300
281 Talkeetna Mts.32N 5&Seward 2150
282 Talkeetna tits.32N 5E Seward 2100
279 Talkeetna Mts..32N 5&Seward 1900
312 Healy 21S 5W Fairbanks 3350
293 Talkeetna Mts.29N 6E Seward 3550
292 Talkeetna Mts.30N 6E Seward 3600
299 Talkeetna Mts.31N 6E Seward 3040
295 Talkeetna Mts.32N 6E Seward 1575
278 Talkeetna Mts.28N 7&Seward 3575
277 Talkeetna tits.30N 7&Seward 3050
280 Talkeetna Mts.30N 8E Seward 2775
306 Talkeetna Mts.32N 9E Seward 2750
214 Talkeetna Mts.30N IDE Seward 1950
Den Sites*"'...,.Talkeetna Mts.27N 2E Seward 2700
Talkeetna Mts.31N 2E Seward 2250
Talkeetna Mts.33N 4E Seward 4150
Talkeetna Mts.225 6W Fairbanks 4750
Talkeetna Mts.22S 5W Fairbanks 4500
Talkeetna tits.22S 4W Fairbanks 3350
Talkeetna Mts.29N 6E Seward 4000
~~-Talkeetna Mts.31N 7&Seward 3850
Talkeetna Mts.30N 7E Seward 4850
*Bear numbers for den site locations are not included to avoid
utilization of this information by hunters in spring 1981.
-
,.,...
-
river in spring 1980 return to these sites in spring 1981,the
hypothesis that the impoundment area is selectively
(preferentially)utilized by brown bears early in the spring will
be supported.Such results were found in a Montana study (Singer
1978)where grizzly bears were observed to concentrate during
spring and fallon the floodplain of the north fork of the
Flathead River where they fed on rhizomatous grasses,several key
forbs,roots and tubers.Singer found this use to be especially
marked in years of heavy snowfall.
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 one of the highest
concentrations of spawning king salmon in the Cook Inlet region
(Larry Engle,pers.comm.).In July,four radio-collared brown
bears (of 11 with active collars)moved to Prairie Creek to fish
for salmon.The first of the radio-collared brown bears that
moved to Prairie Creek was G294,a large male.He was in the Fog
Creek area on June 23 but had moved to Prairie Creek by July 2
and remained there until August 22;he was next seen near
Chunilna Creek in October.
Other radio-collared bears that moved to Prairie Creek in July
and August were G308B,G293,and G283.On August 10,past the
king salmon peak,a minimum of 13 brown bears were verified as
using Prairie Creek (4 marked adults,7 unmarked adults and 2
cubs);local residents have reported seeing 20 bears at one time
on Prairie Creek.Our guess is that 30-40 individual brown bears
fished in this area in the summer of 1980.
50
;"'''''
The importance of the Prairie Creek salmon run to study prea
brown bears will be difficult to evaluate.Other studies (Miller
and Ballard 1980)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 nutritionally
stressed (larger individuals)than adjacent populations without
access to a salmon run.
All of the radio-collared bears seen at Prairie Creek had
portions of their home ranges north of the Susitna River and
therefore 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 in 1980 was five (Table 6).
3.2.3 -Brown Bear Density
An imprecise estimate of brown bear density was obtained from
intensive trapping and mark-recapture techniques conducted in the
Susitna River headwaters in 1979 (Miller and Ballard 1980).This
estimate is compared with other North American estimates in Table
8.
Based on this density estimate of 1 bear/41-62 km 2 ,the
Susitna study area of 3,500 km 2 would have a population of
56-85 brown bears.It is our subjective evaluation that brown
bear density in the Susitna study area is more likely to be
higher than that estimated in our earlier study,rather than
lower.However,using the midpoint of this estimate,70 bears,
it can be seen that only approximately 37 percent of the bears
inhabiting the study area have been captured and that only 15
percent are currently radio-collared.An accurate density
determination may be obtainable only when essentially all brown
bears utilizing the study area have been captured and marked.
51
-
Table 8
Reported brown bear population densities in North America.
0.6
6.0
8.2·
11.0
9-11
16-24
88
(l6-300)
100
1.6
15.5
21.2
28.5
23-27
41-62
288
(43-780)
260
Location
Kodiak Island t AK
Alaska Peninsula t AK
Glacier Nat.ParktMontana
Glacier Nat.Park,B.C.
SW Yukon Territory
Upper Susitna R.,AK
Western Brooks Range
Nat.Pet.Res.t AK***
Eastern Brooks Range,AK
Source
Troyer and Hensel 1964*
Unpublished data (Glenn
pers.comm.)**
Martinka 1974*
Mundy and Flook 1973*
Pearson 1975*
Miller and Ballard 1980
Reynolds 1980
Reyno 1ds 1976
,-
*Taken from Pearson 1975.
**Data refer to a 1800 mi 2 intensively studied area of the central Alaska
Peninsula.
***Mean is for the ~hole of the Nat.Pet.Reserve t AK,the range represents
values for different habitat types in this reserve where the highest
density occurred in an intensively studied experimental area.
-I
3.2.4 -Black Bear Seasonal Distribution and Movements
Relocations in 1980 for 23 radio-collared black bears (excluding
offspring and sequential relocations at the same den site)
totaled 181 points (Table 9);For the 16 bears with active
radios prior to October 1980,143 relocations were obtained (4-19
per individual)(Table 9).Dens were located for 14 of these 16
bears.The two black bears without den site locations had not
been found since early September 1980;possibly their radios
failed.Sightings of unmarked black bears totaled 48,yielding a
total of 229 point locations for black bears in 1980.Complete
analysis of this point location data will be delayed until
digitization is completed and more points are available;only
general and preliminary conclusions from these data will be
presented here.
Black bear distribution in the study area primarily was confined
to a finger of habitat along the Susitna River and its major
tributaries.this finger becomes progressively narrower and
supports fewer bears as one proceeds upstream.We did not see
black bears from Kosina Creek to Clarence Creek;however,reports
indicate that their distribution is continuous to the mouth of
the Oshetna River.Small numbers occur upstream at least as far
as the confluence of the Tyone and Susitna rivers.
Within the study area black bear numbers appear to be much higher
on the north side of the Susitna River than on the south side.
In the spring it is reasonable to speculate that this preference
may result from relatively advanced plant phenology on the
south-facing slopes along the north side of the river.However,
the north side of the river apparently was preferred throughout
the rest of the summer as well,reasons for this are unclear.
53
Table 9
Black bear relocation records for 1980.
1980
Brown Age at Ci'ipture Date-Number No.River 80/81,-Bear #Sex Capture Last Location Relocations Crossings Located
*287 M 10.5 5/1/80 -10/13/80 15 0 yes
*(288)F 10.5 5/1/80 -8/27/80 15 0
*289 F 9.5 5/2/80 -10/13/80 13 4 yes
~*290 F 8.5 5/2/80 -10/13/80 19 4 yes
*(291 )M 3.5 5/2/80 -7/20/80 5 0
(296)M 10.5 5/3/80 -
*(300)M 7.5 5/4/80 -
*301 F 7.5 5/4/80 -10/13/80 19 2 yes
*(302)M 8.5 5/4/80 -8/4/80 5 0
*303 t~7.5 5/4/80 -9/9/80 14 2 no
*304 M 10.5 .5/4/80 -9/9/80 14 0 no
*(305)M 9.5 5/5/80 -8/30/80 8 2
307 r>t 2.5 5/5/80 --310 M 2.5 5/6/80 -
-
*(316)F 12.5 5/7/80 -8/28/80 3 0....*317 F 7.8 8/18/80 -10/13/80 5 0 yes
*318 F 5.8 8/18/80 -10/13/80 5 0 yes
~*319 M 3.8 8/18/80 -10/13/80 5 4 yes
(320)M 4.8 8/18/80 -9/9/80 0 1
~~*321 F 10.8 8/18/80 -10/13/80 5 0 yes
*322 M 4.8 8/19/80 -10/13/80 4 0 yes
*323 M 2.8 8/18/80 -10/13/80 5 2 yes
~*324 M 5.8 8/19/80 -10/13/80 5 0 yes
*325 F 11.8 8/18/80 -10/13/80 5 0 yes
.~*(326)F 5.8 8/19/80 -8/28/80 2 0
*327 F 5.8 8/19/80 -10/13/80 5 1 yes
('#'"*328 F 6.8 8/19/80 -10/13/80 5 0 yes
*Radio-collared-( )I.ndicates dead bear or shed collar.
-
......
-
.....
-
Black bears are well known to be primarily restricted to forested
biomes;this may be because trees are needed to avoid predation
on cubs (Herrero 1972).The distribution of black bears in the
study area follows this pattern.Especially in upstream portions
of the study area,spruce-forested habitats are primarily
restricted to the vicinity of the Susitna River and its major
tributaries;black bears were .seldom observed very far from these
spruce habitats.Black bears occur farther from the Susitna
River in downstream portions of the study area,an apparent
correlation with the wider distribution of spruce forests
downstream relative to upstream.
No quantitative data are yet available on the proportion of black
bear range which is forested,therefore,selectivity or
preference for forested areas in the study area cannot yet be
demonstrated.However,a preliminary and superficial analysis of
the number of point locations of radio-collared bears which
occurred in spruce habitats (habitat categories 1-9)and
non-spruce habitats was attempted (Table 10).As can be seen,
black bears were most commonly found in spruce forested habitats
in the spr"j ng (72%of the poi nt locations in May)and least
commonly found in these habitats in September (35%of the point
locations)(Table 10).Throughout the year 55 percent of the
point locations occurred in spruce habitats.These data probably
underrepresent the importance of spruce habitats to black bears
as many observations classified as in non-spruce habitats were in
close enough proximity to spruce habitats that these habitats
were readily available to the bear should they be needed for
escape or other purposes.This situation can be clarified by
using the vegetation maps that have recently become available.
From the perspective of a black bear it is evident that not all
spruce forests in the study area are equal.Some areas are much
more densely populated by black bears than others that appear
55
Table 10
Monthly occurrence in spruce habitats for 23 radio-collared black
bears in the Susitna study area (capture and den sites not included).
I ----'----------------------------
No.Observations
In In
In Spruce Non-Spruce Unspecified %In
Month Habitats Habitats Habitats Total Spruce Habitats
May 23 9 2 34 72
June 17 9 1 27 65
July 11 14 0 25 44
August 28 24·1 53 54
September 9 17 0 26 35
Totals 88 73 4 165 55
-
-
equivalent with respect to the superficial appearance of the
spruce component.An example of this is the apparent preference
of black bears for the north side of the Susitna River,mentioned
above.Detailed analyses of vegetation composition in these
stands as well as food habits studies and perhaps,behavioral
studies will be necessary to identify the habitat components
which govern black bear distribution and abundance.
Data collected to date suggested that black bears are found least
frequently in spruce habitats in late summer (July-September)
(Table 10).At this time black bears increasingly concentrated
on the tablelands between the Susitna River spruce habitats and
the nearby foothills to the north.Observations as well as feces
collected in August 1980 suggest that bears were seeking the
ripening berries (Vaccinium spp.)which appeared much more
abundant on the tablelands than in the spruce forests.
The most important tableland areas identified included the area
around the Watana campsite,between Tsusena Creek and Delusion
Creek,and the uplands between Devi 1 Creek and Tsusena Creek,
especially the eastern portion of this area (T31-32N/R4E)(Table
11).At the time black bears were using these tablelands,brown
bears occurred primarily at hi gher el evat ions.
Black bears do use the south side of the Susitna River.They
were occasionally located on the Fog Lakes Plateau and other
areas,but data collected to date suggest the south side of the
river is not preferred.One unmarked black bear was seen about 1
mile 1rom Prairie Creek on August 4;however,Prairie Creek
salmon do not appear to be an important food source for Susitna
area black bears.Possibly the abundance of brown bears around
Prairie Creek during the salmon run deters black bears.
Residents of Stephan Lake Lodge report that they have not seen
black bears along Prairie Creek during the salmon run.
57
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-
Table 12
Black bear den sites,1980-81.
Bear
Number
USGS
Quadrangle Township Range Meridan Elevation (feet)
Den Sites
B287 Talkeetna Hts.31N 3£Seward 1750
B289 Talkeetna Hts.32N 6£Seward 1950
B290 Talkeetna Hts.31N 3E Seward 1850
B301 Talkeetna Hts.30N lOE Seward 2000
B317 Talkeetna I1ts.32N 4E Seward 1850
B318 Talkeetna Hts.32N 4E Seward 2500
B319 Talkeetna l'1ts.31N 2£Seward 1300
B321 Talkeetna Mts.31N 3E Seward 2750
B322 Talkeetna Hts.32N 5£·Seward 1950
B323 Talkeetna J1ts.32N 5E Seward 1750
B324 Talkeetna J1ts.31N 4E Seward 2190
B325 Talkeetna Ht.s.31N 5E Seward 1500
B327 Talkeetna l1ts.32N 5E Seward 1975
B328 Talkeetna tits.32N 5E Seward 1725
"""'"
..-
-
--
-
--
-
-
Of the black bears with four or more radio-locations,eight
crossed the Susitna River at least once during 1980 and 12 had no
crossings documented (Table 9).Three black bears were
documented to have crossed the river four times (Table 9).Black
bears crossed the river more frequently than brown bears and a
higher proportion of the black bear population crossed the river.
This was not unexpected as all radio-collared black bears were in
the immediate vicinity of the Susitna River while the home ranges
of many brown bears were not adjacent to the river.Reasons for
frequent river crossings by black bears and the importance of
those crossings to the bear population are not known.
Black bear den sites were located only from the air (Table 12).
Den characteristics,including exact elevation,slope,aspect,
habitat type,will be recorded from the ground after the bears
have left.However,our aerial locations indicated that most
black bear dens were below or near the proposed high water mark
of the proposed impoundments (assuming 2,200 feet for the Watana
dam and 1,450 feet for the Devi 1 Canyon dam.Fi ve dens used by
radio-collared black bear were below the impoundment level
(average elevation=1,925 ft,range=1,750-2,000 ft.).Two of the
nine black bears denning in the impact area of the Devil Canyon
impoundment had dens apparently below the impoundment level
(average elevation=1,935 ft.,range=1,300-2,750 ft.).
All of the dens in the vicinity of the proposed Watana
impoundment are in spruce habitats along the river or tributaries
such as Deadman Creek,and four of the nine black bear dens in
the vicinity of the Devil Canyon impoundment are in spruce
habitats along the river or tributaries such as Tsusena Creek.
60
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......
-
-
-
-
.....
Future studies should be directed at identifying habitat
components critical for black bears and assessing the
availability of these components outside of proposed impoundment
areas.Such critical components may vary between years.For
example,a food source used only lightly during years of abundant
berries might be critical in years of berry crop failure.
3.2.5 -Black Bear Densities
No black bear density estimates are available from the study area
or adjacent areas.Our subjective impression is that portions of
the study area were very densely populated by black bears
relative to other Alaskan habitats.The only available data that
permit even a crude density estimate come from sightings of
marked and unmarked black bears during the August tagging
operation.
In 1 1/2 days of spotting effort (August 18-19),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
presence 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 (Richer 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
on ly a small port i on of the study area at a season when bears
might have concentrated in search of a locally abundant food
source.Regardless,the density estimate of 4.1 km 2/bear
falls roughly at the mid-point of reported black bears densities
in North America (Table 13).Our subjective evaluation is that
further studies in the Susitna study area are more likely to
reveal that the above density approximation is too low rather
than too high,at least in the habitats where black bear density
is highest .
61
-
Tab1e 13
Black bear population densities in various North American 1oca1-
ities (adapted from Modafferi 1978).
Source-Location
mi 2
;per Bear
km 2
Per Bear
*(coastal popUlation)McIlroy (1972)Alaska 0.1 0.3
Lindzey and Meslow (1977)Washington (an island population)0.3 0.8
Poelker and Hartwell (1973)Washington (mainland population)0.7-1.0 1.8-2.6
Piekielek and Burton (1975)California 0.8-1.0 2.1-2.6
-
3.2.6 -Needs for Further Study
A larger proportion of bear populations in the study areas must
be radio-collared in order to clearly establish seasonal use
patterns and more accurately estimate density.This process will
continue throughout the remainder of Phase I and into Phase II.
The most cost-effective time to capture black bears is in early
August when black bears appear to be most visible and vulnerable
to capture.At this same time efforts should be made to mark
black bears in portions of the study area where bears appear to
be less dense,notably from Watana Creek upstream to·the gaging
station at the Vee Canyon.This will provide a more complete
perspective of black bear populations and movements in the
vicinity of the whole impoundment-impact area.Brown bear
tagging efforts will be most effective in early spring
(April-May).
An effort is planned for August 1981 to directly and intensively
census areas of high black bear density and thereby to refine
Lincoln Index density estimates.
Black bear and brown bear dens will be visited and marked in the
winter of 1980/81 for subsequent studies of den site
characteristics.Radio collars will be replaced at this time for
some black bears,and some yearling black bears will be collared
with experimental expandable radio collars to document foci of
black bear dispersal.Both species will be intensively monitored
following emergence from dens in order to document suggested
intensive early spring usage of south-facing.slopes along the
river.
Bear feces will be collected whenever encountered,and the
precise location where feces were found recorded.Feces will be
analyzed to evaluate seasonal food habits during Phase II if
funds are available.
63
1"""
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.....
I
The apparent heavy utilization by black bears of riparian
habitats in the imrnedi ate vicinity of the Susitna River strongly
suggests that downstream bear studies may be needed i~Phase II.
Under impoundment regulation procedures which would restrict
periodic flooding and result in corresponding vegetational
changes,the potential for downstream impacts on bears,
especially black bears,cannot be ignored.Seasonal selection
by bears for early successional,riparan habitats has been
reported for brown bears in Montana (Singer 1980),black bears in
Montana (Tisch 1961)and black bears in California (Kelleyhouse
1980).
Continuity of data on the same animal throughout both phases of
the study is highly desirable.Radio collars placed on bears
during 1980 have a maximum life span of 24 months and cannot be
expected to 1ast unt i 1 the start of Ph ase II.Therefore,
recollaring for Phase II studies should be done during 1981.
These collars should be ordered by March 1981.
3.3 -Caribou
3.3.1 -Distribution and Movements
When field operations began in mid-April 1980 the main wintering
concentration of caribou was spread over an area extending west
and south from the Chistochina River to the Gakona River,along
the southern foothills of the Alphabet Hills and throughout the
Lake Louise Flat.Smaller numbers were also present in drainages
of the upper Nenana,Susitna and Talkeetna rivers and the
Chunilna Hills.During spring (20 April -20 May)two routes of
movements were primarily used;animal s moved from the Lake Loui se
Flat into the foothills of the Talkeetna Mountains in the
vicinity of the Oshetna River and caribou crossed the Susitna
River north to south in the area from the big bend of the Susitna
to Deadman Creek.
64
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-
-
,....
....
-
The majority of females (including 21 of 26 radio-collared females)
utilized the traditional calving grounds between the Oshetna River
and Kosina Creek in the northern foothills of the Talkeetna
Mountains.Twelve of the 21 radio-collared females were seen with
calves.The two females collared in the headwaters of Talkeetna
River remained there through calving (and through the study period
to date).One of these females reared a calf.Three of four
fema 1es collared in the upper Sus itna-Nenana drainages remai ned
there through the calving period.Two of these females were known
to produce calves.The calving period appeared to be about the
.same as previously reported,15 May to 10 June (Hemming 1971).
Since 1949,the first year for which records are available,
Nelchina caribou have utilized an area of about 1,000 square miles
in the northern Talkeetna Mountains for calving (Skoog 1968,
Hemming 1971,Bos 1974).While the precise areas utilized have
varied,calving has taken place between Fog Lakes and the Little
Nelchina River between 3,000 and 4,500 feet elevation.The only
deviations have been during years with extremely heavy snow accumu-
lations when some calving took place during the migration to the
traditional calving grounds (Skoog 1968,Lentfer 1965,Bos 1973).
The main summering concentration of Nelchina caribou occurred in
the northern and eastern slopes of the Talkeetna Mountains between
Tsisi Creek and Crooked Creek.The upper Oshetna and Little
Oshetna rivers appeared to be the center of the summer range.The
caribou generally ranged considerably higher in elevation than
during calving,primari ly between 4,000 and 6,000 feet.One
radio-collared animal was found at 6,800 feet.Additional
summering caribou were found in the upper Talkeetna River,the
Chulitna Mountains and the Butte Lake-Brushkana Creek area .
Additionally,groups of summering bulls were found in the Jay
Creek-Coal Creek area,the Clearwater Mountains,the Alphabet
Hills,the Chunilna Hills and the Amphitheater Mountains.Skoog
(1968)referred to additional summer "bull pastures"in the upper
Nenana,Chickaloon and the Talkeetna river drainages.
65
-
-
-
1""'
Historically,the female-calf segment of the Nelchina herd has
primarily summered in two areas:the eastern Talkeetna Mountains
and across the Susitna River in the Brushkana,Butte,Deadman,
Watana,Jay and Coal creeks complex (Skoog 1968,Hemming 1971).
In 1960 and 1961 some females and calves summered in the Alphabet
Hills and Amphitheater Mountains (Skoog 1968).Postcalving and
summer movements of varying proportions of the female-calf
segment (ranging from 0-100%)from the calving grounds and summer
range in the Talkeetna Mountains across the Susitna River
occurred in most years between 1950 and 1973.Timing of major
movements ranged from mid-May through July.Crossings apparently
occurred between Deadman Creek and the big bend of the Susitna.
In mid-to late August a portion of the main summering
concentrations moved out of the Talkeetna Mountains onto the
western portion of the Lake Louise Flat and in some cases into
the Alphabet Hills.The exact routes of movement were not
determined;however,it seemed that while a few anima~s may have
crossed the Susitna River in the area of the proposed Watana
impoundment,most probably moved onto the flat further to the
east.Through September the distribution remained relatively
stable with the main herd divided between the northeastern
Talkeetna Mountains,the Lake Louise Flat and the Alphabet
Hills.
During the rutting pause the II ma in ll Nelchina herd was found
almost exclusively on the Lake Louise Flat.Several hundred
animals were located on Slide Mountain in the southeastern corner
of the flat.The Talkeetna River and upper Susitna-Nenana
radio-collared animals were not relocated during the rut;
however,they were assumed to have remained in their normal
ranges as they were found there both before and after the rut and
were not found with the main Nelchina herd.
66
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....
During early winter (2-5 December 1980,last survey)there were
two main groups:the largest group was spread from the Maclaren
River east through the Alphabet Hills and along the west fork of
the Gulkana River across the Richardson Highway and trans-Alaskan
pipeline to the Chistochina River;the other group was in the
Slide Mountain-Little Nelchina River area.A few additional
cari bou were scattered through the Lake Loui se Fl at.The upper
Susitna-Nenana and Talkeetna river groups remained in their
normal ranges.
Nelchina caribou have utilized numerous winter ranges during the
past 30 years ranging from upper Nenana-Yanert Fork drainages to
the Ta"lkeetna River east to the Mentasta and Wrangell mountains
(Skoog 1968,Hemming 1971).
3.3.2 -Subherds
Eide (1980)suspected that subherds with separate calving areas
existed in several areas of the Nelchina range.He based this
conjecture on reports of sighting of animals,including young
calves,in these locations during all seasons including the
calving period.Locations of these possible subherds were the
Watana Creek Hills (upper Susitna-Nenana drainages),the
Talkeetna River,Chunilna Hills,Alaska Range and Gakona River.
Because of their proximity to the proposed hydroelectric
development and potential for increased isolation,radio collars
were placed on animals in three of the suspected subherds:
Talkeetna River,Chunilna Hills and upper Susitna-Nenana river
drainages.Because of the changeable nature of caribou movements
and the short duration of the study the results are preliminary
and may be interpreted differently when additional data are
avail abl e.
67
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.....
3.3.2.1 -Talkeetna River
Two adult females and one adult male were collared in late April.
All remained in the area throughout the study period.One
collared female raised a calf.Several other females with calves
were seen.The bull surrmered in the Talkeetna Mountains west of
the main river but returned to the headwaters in the fall.The
tentative conclusion is that this is probably a legitimate
resident subherd composed of approximately 400 animals.
3.3.2.2 -Chunilna Hills
One adult bull and one adult female were collared in late April.
The female died within a month after capture.The bull remained
in the ChunilnaHills through the fall.No sighting of females
and young were made during the calving period.Insufficient data
are available to speculate on subherd status.
3.3.2.3 -Upper Susitna-Nenana
Four adult females and one adult male were radio-collared in
early May.One of the females migrated-to the main Nelchina
calving area,summered in the Talkeetna Mountains,migrated back
through the upper Susitna-Nenana area in the fall and rejoined
the main Nelchina herd during the rut and early winter on the
Lake Louise Flat.The other three females remained in the upper
Susitna-Nenana area throughout the study period,two producing
calves.Other females with calves were seen.The bull surrmered
in the Clearwater Mountains then joined the main Nelchina herd
during the rut in the Lake Louise Flat.One of the main Nelchina
radio-collared adult bulls summered in the upper Susitna-Nenana
area before reJolnlng the main Nelchina herd on the Lake Louise
Flat during the rut.It seems likely that a resident subherd
68
.-.
-
,....
i
of approximately 1,000 caribou exists in this area.However,the
situation is confounded by movements of animals from the main
Nelchina herd through the area and by use of the area by
summering bulls and the main Nelchina herd.
3.3.3 -Population Size and Composition
Census activities were conducted from 2-5 July 1980.
Reconnaissance flights showed that the post-calving female:calf
segment of the main Nelchina herd (including 19 of 20
radio-collared females considered to be main Nelchina animals)
was in an area of about 260 square miles in the southeastern
Talkeetna Mountains.The area was subdivided into three areas
based on geographical features and apparent composition of
animals.A total of 17,061 caribou were counted:9,771 in area
A,2,838 in area Band 4,907 in area C.Composition data from
the three areas (Table 14)indicated significant differences
(Chi-square =143.15,P<O.OOl)in the proportions of males,
females and calves.The composition sampling effort was not
proportional to the numbers of caribou in each of the subareas,
therefore the data were weighted (Table 14)to provide the most
precise estimate of composition possible.An additional 244
caribou (including cows and calves)were found in peripheral
areas and were assumed to have the same compos it i on as the
weighted estimate.Therefore the post-calving aggregation
totaled 17,305 caribou with an estimated composition of 2,808
males ~1 year,9,285 females ~1 year and 5,212 calves.
Fall composition data (Table 15)were collected on 14 October
1980 when the main Nelchina herd was distributed on the Lake
Louise Flat during the rut.The ratio of males ~l year to 100
females ~1 year was 61.9,the highest ever recorded for the
Nelchina herd.While collecting the composition data it was
felt that sampling was probably biased towards males.Large
males were conspicuous.Also,concentrations of males usually
occurred as the back of groups where samp 1i ng began.Often the
69
\
Table 14
Nelchina caribou post-calvin~sex and age composition data,
5 July 1980.
Table 15
Nelchina caribou fall sex and age composition data,14 October 1980.
MM per Calves per Calves Cows Bulls
100 ~100 ~N %N %N %
~
61.9 42.3 .170 20.7 402 49.0 249 30.3
.-
.-
i~
.....
.....
-
-
groups fragmented and animals towards the front were not fully
sampled.An indication that the data may have been
representative or that observer bias has been consistent over
time was the nearly perfect fit (r 2=0.99)of this year1s
ratio with the linear increase which has occurred since 1976.
Indeed an increase in the proportion of males would be expected
for a herd which is increasing and previously had a relatively
low proportion of males.
The estimated fall population was calculated as follows:
18,558=17,305 X 0.537 X 0.978 X (1+1.042),
where 17,305 =the number of animals in the post-calving
aggregation,0.537 =proportion of females in the post-calving
aggregation,0.978 =survival of females from the time of
post-calving counts until fall and consists of an estimated
2.2 percent hunter harvest,1.042 =ratio of bulls and calves
to females in the fall.The figure 18,558 is the fall
population estimate.
In recent times the Nelchina herd has increased from 37,000 in
1956 (Watson and Scott 1956)to 71,000+11,867 in 1962 (Siniff
.and Skoog 1964)and then declined to about 8,000 in 1972 (80S
1973,1975).Since that time the herd has appeared to increase
slowly to the present estimate of 18,558.
3.3.4 -Habitat Selection
Analyses of habitat use and selection are dependent on computer
programs and habitat mapping not yet avai 1able when this report
was prepared.Bos (1974)and Skoog (1968)remarked on habitat
characteristics of the Nelchina calving grounds:2,600 to 4,600
feet elevation,gently sloped,shrub birch,meadow,dwarf heath,
relatively low snow pack and early snow loss.Characteristics of
summering habitat include high elevation,wind exposure,
72
.....
......
scattered patches of snow and ice,grass,sedge,willow,dwarf
birch and forbs (Skoog 1968,Hemming 1971).Suitable winter
habitat characteristics include snow depths <60 em,ice crust
<3.8-6.4 cm,irregular terrain,forest and/or shrub cover,
lichens,sedges,and windswept range (Hemming and Pegau 1970,
Skoog 1968).
3.3.5 -Planned Activities for Remainder of Phase I
Distribution and movement studies and habitat selection studies
will continue through Phase I with routine monitoring of radio-
collared caribou.Increased emphasis will be placed on more
frequent monitoring when animals are near the proposed
impoundment sites,i.e.15 April -15 June and 1 August - 1
.October.To more precisely evaluate subherd status at least two
females will be collared in the Chunilna Hills area and monitored
periodically,particularly during the calving period.
Radio-collared caribou in the Talkeetna River and upper
Susitna-Nenana subgroups will be monitored to better evaluate
their subherd status.Population size of the Nelchina'herd will
again be estimated using the aerial photo-direct
count-extrapolation caribou census technique.
During field activities well-worn caribou trails were noted in
the vicinity of the proposed Watana impoundment.LeResche and
Linderman (1975)and Skoog (1968)both remarked on the value of
mapping caribou trail systems to document historical movement
patterns.Plans include mapping the trail systems in the
vicinity of the proposed impoundments to determine traditional
crossing sites.
73
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.-
3.4 -Dall Sheep
3.4.1 -Watana Hills
The Watana Hills were established as a population trend count
area in 1967 by ADF&G and have been counted seven times since
then.The 1980 count of 174 sheep is higher than the 7 year
average of 160 sheep (Table 16).If the low count of 76 sheep in
1974 is eliminated,the 6 year average is 175,suggesting that
population numbers have remained stable.Also,the percentage of
legal rams and lambs were similar.Some yearly variation is
expected in count data because of differences in observers and
counting conditions ~nd minor population fluctuations.
The distribution of sheep observed in the Watana Creek Hills
trend count area on 22 July indicated that sheep were generally
widespread and all were at elevations above 3000 feet.Sheep
distribution is likely to be more restricted during winter when
deep snow and ice make portions of their range inaccessible.We
would expect greater use of lower elevations,south faclng slopes
and windswept areas during winter.A late February or early
March survey is planned to document winter distribution.
Several observations suggest significant use of habitat that may
be directly impacted by the Watana impoundment.Three sheep
observations reported in June 1980 were near the 2200 foot
elevation on Jay Creek.One group consisted of 23 animals or 13
percent of the number of sheep counted in July.Other
observations at the same time of year were near the 3000 foot
level.The significance of these sightings is not known,however
sheep often use mineral licks at that time of year.Some licks
profoundly influence sheep distribution and movements (Heimer
1973).Two other licks have been identified in the area,but
little is known of their use.Therefore,further investigation
of sheep use of Jay Creek is warranted.
74
-
Table 16
Compilation of highest yearly counts completed in Watana Hills sheep trend
count area .
......
I~
Legal
Rams *Lambs Total
%Legal
Rams
%
Lambs
1950 0 Scott
1967 220 Nichols
1968 183 26.6 Nichols Aug.
1973 10 40 176 5.6 22.7 McIlroy Aug.197:
1974 6 18 76 7.9 23.7 Harkness April
1976 4 30 130 3.1 23.0 Eide Aug.
1977 4 33 152 2.6 21.7 Spraker July 11
f"""1978 5 34 189 2.6 .18.0 Eide July 23
1980 9 42 174 5.1 24.1 Tobey July 22
*A legal ram is defined as 'having a 3/4 .curl or greater horn.
-
~.
-
-
-
-
-
.-
3.4.2 -Mount Watana
An intensive search from Mt.Watana to Grebe Mountain resulted in
a total of eight sheep (1 ram,7 unidentified)being observed.
While few historical data from this area exist,past observations
indicate that larger numbers of sheep sometimes occupy this area.
For example in 1977,34 sheep were seen on Mt.Watana.Numerous
observations have been made around Terrace Creek in recent years
and a few sheep have been harvested in that vicinity from this
area.Either sheep moved from the area or they were missed on
the 1980 survey.
The pattern of sheep distribution to the south of the survey area
suggests that sheep using the Mount Watana area may be part of a
larger Talkeetna Mountains population (ADF&G 1973).
3.4.3 -Portage -Tsusena Creek
A total of 72 sheep (6 legal rams,12 lambs and 54 unidentified)
was counted in the Portage Creek and Tsusena Creek drainages.
The only previous ADF&G survey in this area was a 1977 count of
91 sheep (8 legal rams,18 lambs,65 others).The 1977 survey
included the Jack River drainage which was not surveyed in 1980.
The sheep sighted were fairly high in the drainages and
relatively far from proposed impoundments.Sheep may concentrate
closer to the Susitna River in winter and may occupy habitat
close to potential access routes.Therefore a winter
distribution survey of the area will be conducted.
3.4.4 -Hunter Use
The 1980 harvest within the Susitna sheep study area was 13
sheep.Ei ght of these were cons i dered to be trophy quality with
horn lengths greater than 35 inches.Most of the harvest
occurred in the Watana Creek Hills.
76
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-
-.
3.5 -Wolverine
From 10 April to 7 May 1980,five adult wolverine (4 males,1 female)
were captured and outfitted with radio collars.Capture of additional
wolverine was precluded by poor tracking conditions caused by an early
spring breakup.One male (941)died 2 days after capture due to
capture related causes.Contact was lost with both 042 (fate unknown)
and 044 (probably dropped collar)after 16 August and 9 October,
respectively.Tagging locations and physical measurements are given in
Table 17 and data on drug action in Table 18.Since the Sernylan was
outdated,induction times of wolverine immobilized with this drug may
not be indicative of normal induction times.The two successful M-99
immobilizations suggest that M-99 may be an adequate substitute for
Sernylan (which is no longer available commercially).
3.5.1 -Movements and Habitat Selection
From April through December 1980,two wolverine were located on
86 occasions.Wolverines were visually sighted on 33 (38%)of
the 86 locations.Home ranges were determined for all four
wolverine,summer ranges for wolverines 042 and 044,and
spring-fall ranges for 040 and 043 (Table 19).
The spring-fall ranges of 399 and 272 km 2 for two adult males
are well below those for the Brooks Range,Alaska,where I~agoun,
(1979)reported an average male had a home range of 615 km 2 .
Similarly Krott (1959)believed a male wolverine could have a
territory as large as 1,000 to 2,000 km 2 depending on food
supply and competition from other species.In contrast,
Hornocker (in press)reported an average home range of 388
km 2 for males and 100 km 2 for females.Bjarvall (in
prep.)calculated home ranges for three lactating females (during
different years)in Sweden to range from 109-221 km 2 (mean =
170 km 2 ).These reported ranges were somewhat larger than
77
-
Table 17
Tagging location and physical measurements of wolverine captured in the
Susitna River Basin,1980.
.-
Accession
Number Date Location
Est.
Sex Age Weight
Body
Length
Table 18
Drug type,dosage,and subsequent induction .time for
wolverine captured in the Susitna River.Basin,1980.
Induction Recovery
Time TimeAccession
Number Date
wt.
Sex (kg)Age Drug Dosage (min.)(min.)
116040
116041
4/10/80 M
4/19/80 M
14.5
15.5
7-12
2-3
Sernylan
M-99
0.25cc
2mg
36
4
116042 4/19/80 F 9.5 2-3 Sernylan,0.25cc 11 90
Rompun
116043 5/06/80 M 17.7 1-2 M-99 0.4cc 14 7
Rompun 0.5cc
116044 5/07/80 M --M-99 0.4cc 12 2
Rompun O.Scc
-
,-.
-
Table 19
Summary of home range size for four radio-collared wolverine in the
Sus itna Ri ver Bas i n ~1980.
Accession
Number .Sex Est.Age
Home
Range {km2 }
Greatest
Length Across
Horne Range (km)
-..
.....
040 M Adult 399 -spring-fall 35.5
042 F Adult 86_summer 15.2
043 M Adult 272 _spring-fall 19.4
044 M Adult 378 _summer 49.8
Table 20
~omparison of annual wolverine harvests from 1962-63 through 1979-80
in Game Management Unit 13.
Year Harvest Year Harvest
1962-63 37*1972-73 140***
...-1963-64 32*1973-74 121***
1964-65 65*1974-75 96***
1965-66 102*1975-76 105***
1966-67 132*1976-77 85***
1967-68 86*1'977-78 58***-1968-69 No Data**1978-79 69***
1969-70 No Data**1979-80 57***-1970-71 No Data**
1971-72 75***
f*""
*Harvest figures are from bounty records.
**The bounty was discontinued on wolverines during this
period,and no information on the harvest is available.
***Harvest figures are from sealing recor~s.
..,..
......
-
.-
-
the home range of the lactating female 042 in this study,which
was 86km 2 .Differences in observed home range size between
Brooks Range and Susitna basin wolverine may result from
differences in sampling intensity.However,we would expect the
greater diversity and abundance of food items found in the
Susitna basin to permit smaller home ranges .
All four collared wolverine showed a fidelity toward shrub (shrub
willow and dwarf birch)dominated habitats,such habitats
accounted for 54 percent (44 of 81)of the relocations.Using
the vegetation maps,the percent occurrence of each habitat in
the wolverine's home range will be calculated and inferences
about wolverine habitat selection will be determined.Also,it
will be very beneficial to characterize wolverine habitat by
available prey species.Coordination between investigators of
the small mammal,the ungulate,and the predator studies will be
necessary to determine prey distribution.
In relation to topography,the four radio-collared wolverine
appeared to favor southerly and westerly slopes.There was some
evidence that the Susitna River formed a partial barrier to
wolverine movements during the ice free period.No track
sightings were observed on the main Susitna River,although we
did not purposely search for them.There were only three
occurrences of river crossing by radio-collared wolverine during
the entire study period.All crossings (two by 040,one by 044)
occurred during early spring,when the river was open but at
reduced flow.Home ranges of the three male wolverine appeared
to parallel the river as the greatest distance across their home
ranges runs from east to west.Also,only 9 percent (6 of 66)
locations were within 0.5 km of the river.Both Magoun (1979)
and Hornocker (op.cit.)indicated that rivers were not barriers
to wolverine movements.However,in both studies,rivers were
much smaller than the Susitna which can reach flows of 90,000 cfs
82
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during the summer (U.S.Army,Corps of Engineers 1975).The low
number of locations during the winter does not allow any
inferences about usages of the river when it is frozen.It is
known,however,that wolf packs in the study area use it as a
travel corridor (Ballard et al.1980).
Wolverine 043 also exhibited a gradual change in home range
usage.Between 6 May and 27 June 1980,11 of 14 observations
were east of Devil Creek.However,from 27 June to 4 December,
all observations were west of Devil Creek and east of Portage
Creek.Without any knowledge of prey availability or
distribution of females,it is impossible to make any inferences
on the shift of home range preference of 043.Increased
monitoring during the next spring and summer may give an
indication how these different areas fulfill 043 1 s seasonal
requirements.
Wolverine 044 was collared on the Susitna River across from
Stephan Lake on 7 May 1980.By 13 June 1980,044 had moved
approximately 70 km to the vicinity of Kosina and Tsisi creek
drainages.It remained there until 26 August when it began
moving back toward Stephan Lake.On 7 October,044 was located 6
km east of Stephan Lake.Contact was lost after 8 October due to
a probable slipped collar.This extensive movement after
collaring went from a heavily timbered habitat to an upland shrub
and tundra habitat.We suspect that timing of movement may be
correlated with peak emergence of Arctic ground squirrels and
marmots,which are more abundant in these higher,more open
habitats.Ground squirrels and marmots are an important food
species for wolverine in the Brooks Range (Magoun op.cit.)and
northwestern Montana (Hornocker op.cit.).On several occasions
duri ng the summer we observed wol veri ne with ground squi rrel
kills.
83
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-
3.5.2 -Ground Tracking
Ground tracking trips conducted in mid-May and early December
1980 indicated that wolverine were preying on small mammals.On
15 May,a fresh set of tracks of an uncollared wolverine within
043 1 s home range was followed for approximately 5 km.Along this
route many ground squirrels were observed and four squirrel
tunnels had been excavated by the wolverine.There was no sign
of capture.The wolverine was followed predominantly through
alpine tundra and upland willow habitats.
On 1 December,wolverine tracks were followed along the north
side of Watana Creek through a white spruce-Salix habitat which
was interspersed with alder thickets corresponding with small
drainages.The tracks were followed for approximately 5 km.The
wolverine appeared to be hunting red squirrels.While in white
spruce (Picea glauca)habitat,the wolverine appeared to
investigate trees where squirrels had been present.He had
excavated two red squirrel middens.As the wolverine came to an
alder thicket,it crossed the thicket with no deviations,
suggesting lack of preference for this habitat type.No evidence
of a kill was observed.
3.5.3 -Carcass Collection and Analyses
Thirty-three carcasses were purchased from local trappers.
Morphometric measurements,age,sex,and reproductive condition
of the carcasses will be presented in the final report.
3.6 -Downstream Moose
On April 17,1980,during collaring operations only 10 moose of the
scheduled 20 were radio-collared.At that late date and after a
reconnaissance flight revealed few moose on the Susitna River1s flood-
plain,it was assumed that only "res ident ll moose remained.
84
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.-
r--,
LeResche (1974)described three types of moose movement patterns.Type
A were those moose that only moved short distances between seasonal
ranges with little change in elevation.Another name for this type is
"res ident".Type B moose move medium distances between two seasonal
ranges with significant differences in elevation between low winter and
high summer-fall ranges.Moose of the Type C pattern move medium to
long distances between three distinct seasonal ranges and significantly
change altitude between low winter and high summer-fall ranges.
Much of the snow had melted by the April tagging operation,thereby
exposing moose forage at all elevations.Moose activity along the
river had substantially decreased,and it was thought that the Type B
and C moose had left the river for higher elevations.As it turned
out,moose exhibiting all three types of migratory behavior were
collared.However,sample sizes were too small to fully assess
population identities along the lower Susitna River.Future collaring
efforts must have broader distribution on the wintering areas of the
river to ensure that all subpopulations of moose are sampled.
Of the ten moose originally radio-collared,three females have shed
their collars and one bull was killed during the September hunting
season.The collars were put loosely on some moose because of their
young age (mean age of the 10 collared moose was 3.5 years),small size
and anticipated growth.When they shed their winter pelage,the
coll ars were loose enough to sl ip over their heads.In the future,the
co 11 ars wi 11 be fastened tighter and the des i gn mod if i ed to make them
less slippery.
3.6.1 -Population Distribution
The number of collared moose,currently six,and of radio-
locations,131,though small,have been sufficient to show that
the downstream moose population is made up of sUbpopulations
quite different with regard to seasonal movements and habitat
use.Some individuals were virtually sedentary during the nine
85
-
--
months of observation.while others used distinctly different
seasonal ranges.It will remain in future work to establish the
relative proportion of the population in each subpopulation.
From moose wintering on the river below Talkeetna.it was learned
that some calve.summer.rut.and possibly winter in the flats
west of the Susitna;some calve.summer.rut and possibly winter
in the forest between the river and the mountains;while others
spend spring.summer.fall and possibly winter in the western
benches and drainages of the Talkeetna Mountains.No specific
calving areas were recorded.but several rutting areas were
documented.The latter were found deep into the creek and river
drainages of the Talkeetna Mountains and on the benchland near
timberline at the mouths of these canyons.Rutting bulls in the
lowlands aggregated less and were frequently alone or in small
groups of 2-4 moose.
Analysis of home range size,chronology of migration and
distances of migration at this time would not be meaningful
because of small sample sizes of observations.In general.the
home and seasonal range size was quite varied.Because there
were some lI res ident ll (Type A)moose.home ranges were as small as
approximately 25 mi 2 .Seasonal ranges were often smaller.
Type C moose had home ranges as large as 90 mi 2 or more.The
timing and distances of migration were equally as varied.One
cow moved from her summering to rutting area in early August
while another did so in late September.The longest distance
traveled between summering and rutting areas was 40 miles.
Home range size and migration distances were likely intermediate
to those found for moose in other parts of Alaska or North
America.This was a function of physiography where all life
requisites were available between an area just west of the
Susitna River eastward to the Talkeetna Mountain benches.Longer
moose movements were unnecessary.
86
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~I
,'
I,!
.~
3.6.2 -Use of Riverine Habitats
A census of moose on and near the river is planned for later this
winter.Rausch (1958)stated that the period of peak moose
abundance along the railroad between Houston and Talkeetna was
February and that movement from the foothills to the railroad
tracks was a basic seasonal movement and was influenced but not
necessarily caused by deep snow.Therefore,the peak use of
riverine habitat also will be in February or early March,and the
timing of the census should correspond to this moose use.
However,the 'magnitude of moose use of Susitna riparian habitats
may be correl ated with the amount of snow cover.If the open
winter continues as it has in 1980-81,the degree of moose use
along the river may greatly underestimate that of a more "normal"
wi nter snowf a11 .
Attempts to devise methods for determining moose use of the river
at seasons other than winter failed.Only general impresstons
and not quantitative data could be stated.It was obvious from
boat trips up and down the river in late May and June that a fair
(quantity unknown)number of cows calved on islands in the river.
Four cows with newborn calves were observed on the ri ver and
tracks of several others were seen on mud banks of islands.
Islands in other areas were frequently used for calving because
they were relatively predator free (Stringham 1974).
Nothing has yet been done to determine summer use of the river.
The untimely theft of the project boat and motor precluded access
to the river at that time.Flooding of much of the lowland areas
of the river in July likely caused moose to leave the floodplain
for higher ground adjacent to the river.
87
-
",..
In fall it also appeared (from overflights but no quantitative
data)that moose did not remain on the river floodplain.However,
they were observed crossing the river by ADF&G biologists.Hunter
success along the river in September also indicated that moose
were either on or near the river in fall.Analysis of hunter
report data,however,is not feasible because hunters are often
secretive about the exact location of their moose kills.
In summary,moose use of ripari an habitats along the lower
Susitna River is greatest in winter,particularly winters of deep
snow,is at least moderate during calving and during the fall,and
is of an unknown level in summer.
3.6.3 -Browse Utilization
The riparian zone was sampled by means of 12 transects containing
840 plots.On each plot containing woody plants available as
moose food,the amount available and degree of browsing,by
species,was determined.The greatest density of browse plants
(3.3 plants/m2)occurred on abandoned agricultural fields.
The mean for all habitats was 1.4 plants/m 2 .
Willow was of particular interest because of the general belief
that it is an important winter food for moose.Disturbed areas
supported a greater density of willow than most other habitats,
suggesting that natural or artificial disturbances favor this
plant.It was used rather heavily,with a mean rate of use of
36.5 percent of that available.
Comparable mean use of other shrubs was found to be:cottonwood-
16.2 percent;birch -26.9 percent;highbush cranberry -15.9
percent;rose -10.0 percent.This finding draws attention to
birch and suggests that this shrub merits more investigation in
the study regi on.Although it is not an important mOOSe forage
plant on the river floodplain,it is well utilized on upland
sites.
88
-
".."
-
""'"',
""''1i
-
-
Much alder was observed while the browse transects were being
conducted,and at no time was it consistently taken by moose,
although a few individual alders were browsed very heavily.In
most areas it was taken,if at all,only in small quantities.
These preliminary studies have shown that there is a great deal of
variability in the vegetational mosaic on and near the river,both
with regard to species composition and growth form.With further
investigation it should be possible to gain considerable insight
into the ecological processes controlling the dynamics of this
vegetational mosaic and so point the way toward potential
management for increased available moose forage.
3.7 -Upstream Moose
3.7.1.-Home Range
Moose move within a home range and often use different seasonal
home ranges.LeResche (1974)reported that seasonal home ranges
of moose were consistently small regardless of how far a moose
moved between seasons.Home ranges determined in the present
study were consistently larger than the 5-10 km 2 (2-4 mi 2 )
he reported (Table 21).Winter home ranges in the present study
range from 21 to 389 km 2 (8-150 mi 2 ),averaging 103 -
km 2 (39 mi 2 ),while summer home ranges varied from 8-210
km 2 (3-81 mi 2)and averaged 72 km 2 (28 mi 2 ).
Total areas occupied by individual moose (migratory and sedentary)
were quite large,ranging from 44 to 1373 km 2 (17-530 mi 2 )
and averaging 339 km 2 (131 mi 2 ).These latter figures
compare favorably with the total range given by Peterson (1955)
for Ontario moose,but are considerably larger than those reported
for Kenai Peninsula moose (Bailey etal.1978).
89
-
Table 21
Reported home range size,cows with calves (LeResche 1974).
.....
LeResche (1974)summarized studies indicating that cows with calves
have smaller home ranges for a short time following parturition than
do cows alone.This also appeared to be true in the present study.
The moose of the present study have tended to use the same seasonal
ranges from year to year,as others have found (Van Ballenberghe
1978).However,individuals occasionally changed seasonal ranges,
especially in winter.
3.7.2 -Plant Community Use
Plant communities within which moose were located,and the monthly
total of such observations,are given in Table 22.There is a rough
correspondence between the elevational distribution of plant
communities and the seasonal elevational preferences of moose.
3.7.3 -Population Identity
On the basis of movement patterns of radio-collared moose,four
discrete populations of moose were identified,as follows:
3.7.3.1 -Clearwater Mountains Western -Alphabet Hills Population
This population apparently consists of a highly migratory segment
and a resident segment.Cows tagged in the Clearwater Mountains
were extremely migratory.Most occupied the area only during late
summer and fall.During November these animals migrated down the
Maclaren River and Clearwater Creek to the bottomlands along the
lower Maclaren River.Some moose wintered in the lower Maclaren
area where they shared winter range with other moose which resided
in the area year-round.Other Clearwater moose and some from the
Maclaren River continued migrating south.These moose either
followed the Susitna River or travelled through the Alphabet Hills
down Monsoon Lake Creek where they eventually wintered either in old
spruce burns on the south side of the Alphabet Hills or at the
mouths of the Oshetna and Tyone rivers.
91
,~
Table 22
Percentage utilization of plant communiti es by month,
Months
J F M A M J J A S 0 N D
Community
Tall Spruce 6 12 5 27 15 13 6 29 13.19 8 18
Medium Spruce 38 48 49 49 52 36 31 29 31 29 39 23
.....,Low Spruce 38 9 22 4 12 13 13 10 15 10 19 5
Riparian
Will ow 0 15 11 10 8 7
9 3 2 4 17 27
Marsh 0 0 0 0 2 2 4 5 0 0 0 0
Alder 0 0 3 5 0 5 10 8 4 8 0 0
Upland
Will ow 19 15 11 5 10 21 21 16 33 31 17 23
Cottonwood
or Aspen 0 0 0 0 0 2 4 0 2 0 0 5
Sample
Size 16 33 37 41 132 167 67 62 52 52 36 22
""'"I
3.7.3.2 -Upper Susitna River Population
Moose from this population generally were year-round residents of
the east,middle,and west forks of the Susitna River.Most made
relatively short movements,moving from higher elevations in
summer to lower elevations in winter.The mouths of Valdez and
Windy creeks and the junction of the forks of the Susitna River
received heavy moose usage through fall,winter,and early
spring.This population1s movements appear to correspond closely
to the drainage patterns of the upper Susitna River.
3.7.3.3 -Upper Nenana-Brushkana Population
Moose from this population appear to be comprised of animals
residing in the tributary drainages of the upper Nenana.These
moose occupy the upper drainages in fall and summer but winter in
lowland areas where they share winter range with year-round
residents.Evidence suggests that some individuals may make
extensive fall migrations down the Nenana River.There appeared
to be a noticeable distinction between animals from this area and
those utilizing the upper Susitna River drainages.Obviously,
some exchange between these two populations occurs and,in fact,
they may not be separate populations.
3.7.3.4 -Susitna River Population
On the Susitna River from Butte Creek down to Devil Canyon most
of the study animals exhibited relatively short movements and had
small home ranges.Movements were mostly altitudinal in nature
with the exception of those cows tagged in upper Butte Creek.
Those moose migrated down the Susitna River or Butte Creek where
they wintered either at the mouth of Watana Creek or the vicinity
of the Susitna bend.There did not appear to be much interchange
of animals in an east-west direction.Existing evidence
indicates these resident moose share winter range with other
highly migratory populations.
93
3.8 -Wolves
Data on wolf populations reported here is drawn from project reports on
Nelchina Basin Wolf Studies (Ballard and Spraker 1979,Stephenson
1978).Unless otherwise noted,this information pertains to the whole
of Game Management Unit 13.
3.8.1 -Packs and Pack Attributes
Up through 30 June 1980,103 individual wolves had been radio-
collared in the study region.These were associated with
approximately 22 different packs.The radio-collared wolves were
relocated on 3~525 separate occasions;resulting in 6,927 wolf
sightings.Wolf territories were for the most part non-
overlapping,but there appeared to be changes in territory
boundaries from year to year.Territory sizes for 14 intensively
studied packs ranged from 268 to 864 mi 2 •averaging 537
mi 2 .Territory size appeared to increase for larger packs
and for those packs in areas of low moose density.
3.8.2 -Relations to Prey
Radio-collared wolf packs were observed on 360 individual prey
kills.38 (10.6%)of which were also occupied by one or more
brown bear.Moose comprised 72 percent of the observed kills.
Calf and short-yearling moose comprised 20 percent of the total
kill.Wolves were preying upon short and long-yearling age
classes from January through July disproportionately to their
presence in the moose population.Moose calves 0-6 months of age
comprised only 6 percent of the kills.
94
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I""'f
i
Four thousand two hundred and ninety food items were identified
in 3,624 wolf scats collected at den and rendezvous sites during
a five-year period.Overall,calf moose was the most frequently
identified food item (44%).Percent occurrence of various prey
items in wolf scats is generally related to prey abundance.
Occurrence of calf moose in scats was correlated with subsequent
fall calf-cow ratios,suggesting that wolves were preying upon calf
moose in proportion to their abundance.Scat data were converted to
numbers of individual prey eaten which was then extrapolated to GMU
13 spring wolf population estimates.This analysis suggested that
wolves in GMU 13 were preying upon from 434 to 1,013 moose calves
annually from mid-May through mid-July.
One hundred twenty-five moose and 25 caribou kill s were examined
..:!..!!.situ to determine both cause of death and age and physical
condition of prey taken by wolves.One instance of surplus
killing of caribou by wolves was reported.The fat reserves of
calf and short-yearling moose killed by wolves were significantly
higher than those of calves dying from both accidental causes and
winter kill.The conclusion was that the wolves were preying upon
relatively healthy calf and short-yearling moose.
To determine whether age bore any relation to causes of moose
mortality,the mean age of the moose att ime of tagging can be
considered a rough average for the population,and the two main
classes of mortality -wolf and winter -can be compared to it.
Tagged moose averaged about 7 years while wolf-killed moose were
between 14 and 15 years of age.These findings suggest that wolves
kill moose that are past their prime but far from ancient.Analysis
of patterns for mild and severe winters showed that in mild winters
older moose were preyed upon more heavily while during a severe
winter wolves preyed upon adult moose of various ages in proportion
to their presence in the population.A severe winter,then,tips
the moose-wolf relationship in favor of the wolf.
95
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;I
Wolf predation upon caribou appears to be related to snowfall,since
most caribou predation was observed in a winter (1978-79)of heavy
snow.The cari bou taken were of both sexes and a range of ages,and
were generally in good physical condition.So as in the case of
moose,it appears that caribou are rendered more vulnerable to wolf
predat i on by heavy snow.
Quantification of wolf predation on moose,their principal winter
prey,was possible through analysis of detailed records for
representative packs.Table 23 summarizes this information for five
packs ranging in size from two to nine wolves.The pack of two killed
considerably more than they could consume,having over 16 kg (35 lb)
of food available to each of them daily.The other packs were all
quite similar in having 5-7 kg (11-15 lb)of food available per wolf
per day,with one ungulate kill every four or five days.An estimate
of the summer wolf predation on moose in Game Management Unit 13 is
given in Table 24.Assuming a daily consumption rate of 5.8 kg (12.8
lb)per wolf per day,it is calculated that the mid-May through
mid-July kill of adult moose,over a five-year study period,varied
from 37 to 132,while the take of calves varied from 434 to 1013.
During the same period an annual average of 33 adult caribou,191 calf
caribou,168 beaver,361 muskrat~1100 snowshoe hare,208 squirrel,
and 4016 microtine rodents were consumed by the wolves of GMU 13.As
mi ght be expected,there are major differences from year to year and
pack to pack in wolf diet within the Susitna basin.
3.8.3 -Population Studies
Wolf populations are at their annual high in the fall,when the pups
join the pack,and at their annual low in the spring,when the losses
due to mortality and dispersal have been felt.Trapping and shooting
by humans appears to be a significant source of mortality,as
evidenced by population increases in areas closed to these activities.
96
-
Table 23
Summary of predation statistics derived from intensive radio-mo:nitoring
of the Sus itna and Tyone wolf packs duri ng.wi nters 1978-79 -and 1979-80
in Game Management Unit 13 of southcentral Alaska.
-.
Size of
wolf pack
Kgs of available
food/day/pack
Kgs of available
food/day/wolf
Days/ungulate
kill
~.9 60.1 6.7 3.6
8 38.9 4.9 4.9
7 36.9 5.3 4.2
4 22.9 5.7 4.0
2 32.8 16.4 8.3
-
Table 24
Estimated number of prey individuals consumed by Game r~anagement Unit 13
wolves for a 61 day period ranging from approximately mid-May through
mid-July 1975 through 1979 as extrapolated from wolf scat analysis and
wolf population estimates.
Estimated number-Assumed weight of prey consumed by GMU 13 wolves based1/
(kg)of prey upon consumption rate of 5.8 kg/wolf/day-
Prey (from Table 44)1975 1976 1977 1978 1979 Subtotal
Adult moose 427.5 132 90 45 37 42 346
Calf moose 39.0 435 1013 829 490 434 3201
Adul t caribou 145.0 -~7?/59 11 14 49 133
Calf caribou 12.0 246 117 75 329 864
Beaver 12.5 286 160 126 250 19 841
Hllsktat 1.4 59 476 542 520 206 1803
SIlO\~shoe hare 1.8 2494 1163 551 571 722 5501
Squirrel .5 498 190 116 26 830
Hicrotine rodents .1 2490 5710 6420 2570 2890 200BO
Totals 6491 9107 8757 4553 4691 33599
1/Estimated spring GMU 13 wolf population was as follows:1975 -235.,
1976 -269,1977 -165,1978 -121,1979 -136.
~/Adult and calf caribou combined.
"...,
_.
To determine wolf population densities in a biologically sound manner,
it is necessary to identify those portions of the landscape that are
not wolf habitat.In the present study it was established that
glaciers and areas above 4000 ft.(1,219 m)were n6t frequented by
wolves.Estimates for various years,for the study region,vary from
37.6 -121.7 mi 2 per wolf (97-315.2 km 2/wolf),a range that
spans many wolf population density estimates from parts of boreal
North Ameri ca where wolves are subject to shoot i ng andtrapp i ng.The
reported wolf density in Mt.McKinley National Park,where wolves are
protected,24-42 mi 2 per wolf (64-109 km 2Jwolf)(Haber 1968)
suggests that wolf densities would be greater if protected from man.
A relationship between habitat productivity and wolf population
density is suggested by the substantially higher wolf population
density estimates for temperate Minnesota and Ontario (Table 25).
99
Table 25
Summary of reported wolf densities for North America.-
Wolf density Size of study area
mi 2 /wolf 2kIn /wolf .2m1 km 2 Location of study area Source
Artificial situation -four wolves transplanted to Island.
Wolves concentrated on caribou winter range.
Maximum abundan,p on winter range.
60-120 155-311
65-124168-32187-111(10~/)225-287
88 228
120 311
200 518
-1/
2/
'1./
10
10.6
......12.9-55.2
Merriam 1964
Peterson 1976
Kuyt 1972
Mech 1966
Parker 197,3
VanBallenberghe
et al.1975
Pimlott et al.
1969
Olson 1938
Mech 1973
Fritts &Mech
In Press
Stenlund 1955
Haber '1968
Atwell et al.
1963
Peterson 1978
Stephenson 1977
This study
Banfield 1951
Mude 1944
Rausch 1967
Fuller &Keith
1980
Kelsall 1957
Stephenson 1975
Cowan 1947 '
Carbyn 1974
Clark 1971
Parker 1973
Coronation lsI.,Alaska
Isle Royale,Michigan
NW Territories
Isle Royale,Michigan
Manitoba-Saskatchewan
Minnesota
Algonquin Park,Ontario
Minnesota
Minnesota
Beltram,lsI.St.For.,
Minnesota
Minnesota
Mt.McKinley Nat.Park
Alaska
SE Alaska
NW Territories
NC Brooks Range,Alaska
W.Canada
W.Canada
Baffin lsI.,Canada
Manitoba-Sasketchewan-
NW Territories
Kenai Peninsula,Alaska
Tanana Flats,Alaska
Nelchina Basin,Alaska
Saskatchewan
NcKinley Nat.Park,Alaska
Nelchina Basin Study area,
Alaska
NE Alberta
2,590
78
544
995
544
3,300
1,857
6,449
10,886
313-2584
10,619
3,885
19,425
2979-4779
18,130
5004-11663
5,180
51,800
25,000
1,243,200
9,324
10,878
1,536
4,662
282,310
30
210
384
210
1,274
717
1,000
7,500
4,100
1,500
2,490
4,203
121-998
1150-1845
7,000
1932-4503
2,000
20,000
9,653
48,0000
3,600
4,200
593
'.800
{C j,000
151
7.8
11.9
17.9
18-26
20.2-35.7
23.8
26
26
27.5
33.3-142.9
44
62-109
65-104
65-75
91
97-315.2
104-215
130
130
10
17
24-42
25-40
25'-29
35
37.6-121.7
40-83
50
50
58
31/
4.6 2 /
6.9-
7-10
,.....7.8 -13 .8~/
9.2
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4 -IMPACT ASSESSMENT
4.1 -Construction Impacts
4.1.1 -Watana Dam and Reservoir
The increase in human activity that will be necessitated by dam
construction will probably cause an avoidance reaction on the part of
brown bears,wolves,and wolverines.Other big game now using the
immediate operations areas will probably avoid it or be subject to
predation by humans.Some estimate of the magnitude of the habitat
loss for each species can probably be developed by a study of present
radio-marked individuals in relation to present sources of disturbance
within the study region.For example,it has already been noticed
that there have been no sightings of wolverines or of their tracks
within 10 km of Watana camp.
Flooding will inundate much of the forest habitat now used intensively
by black bears,the present black bear denning habitat,and a
substantial stretch of river-bottom now used by moose in winter.
Upland borrow areas,when they have been mined for gravel,will
represent areas of habitat lost.
At the time this study was designed it was assumed that the only
significant impact of the Susitna Hydroelectric Project on Da1l sheep
would be from disturbance from construction activities,helicopter
traffic,etc.Such impacts could be moderated by avoiding areas used
by sheep or schedu1 ing activities at seasons when sheep use of an area
was reduced.However,sightings of sheep along Jay Creek indicate a
possibility of direct loss of habitat.
The Portage -Tsusena Creek sheep are likely to be impacted only
by disturbance.With adequate data on seasonal distribution
serious disturbance probably can be avoided.The status of the
Mount Watana population is less clear.Limited data indicate that
101
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sheep occupied habitat close to the proposed Watana impoundment where
disturbance and perhaps even habitat loss could be problems,but this
distribution was not confirmed by the July 1980 survey.More
information is needed.
The Watana Creek Hills population appears to be the most
vulnerable of the three sheep populations.Its close proximity
to the Watana impoundment and possible access routes makes
disturbance a concern.The possibility of loss of seasonally
important habitat has been raised by sightings of sheep on Jay Creek
in June.The Watana Creek Hills population appears to be relatively
isolated from other sheep populations.If the population were reduced
below carrying capacity,recovery might be slower than it would be in
a less isolated population where immigration from unaffected areas is
more likely.
The scope of the Phase I sheep studies is not adequate to fully assess
the impact of habitat loss.An attempt will be made to further
document the use of lower elevations along Jay Creek in spring of
1981,but if a special attraction such as a mineral lick occurs there,
expanded studies including ground observations and marking of animals
would be necessary to evaluate its use.
4.1.2 -Devil Canyon Dam and Reservoir
Preliminary observations of brown bear denning sites in the study area
suggest that the proposed impoundments would have little direct impact
on the availability of brown bear denning sites.Most brown bear den
sites found were well away from the river and at high elevations in
the foothills or mountains surrounding the Susitna River (Table 7).
The lowest den and that nearest to the river was found at about 2200
feet elevation about 3 km from the Susitna River,above the height of
the Devil Canyon impoundment.It is likely that some brown bears den
in areas which would be directly flooded by the impoundments,but this
has not yet been documented.
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The Prairie Creek salmon run is now heavily used by brown bears.The
proximity of the Devil Canyon site,and associated roads and human
activity to brown bear travel routes makes a negative impact probable.
Preliminary conversations with sports fish biologists (ADF&G)
suggest that Prairie Creek salmon runs are unlikely to be
negatively 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 is a physical blocking
of seasonal movements to Prairie Creek.
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 occur in mid summer)might represent an
equal or greater barrier,perceived or real,to bear movements
across the impoundments.Heavily traveled access roads to the
impoundments might also inhibit or block bear movements across
these roads;any access road built from the Parks Highway to the
Watana damsite would have to be crossed by some bears moving to
or from 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 1981).On the Alaska
Peninsula,Lee Glenn (ADF&G pers.comm.)has observed movements
of up to 50 km by bears enroute to McNeil River to fish for
salmon.In our 1980 studies,the farthest a Prairie Creek bear
(G293)was seen from Prairie Creek was approximately 100 km
northeast of Prairie Creek.
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4.1.3 -AccesS Road
Construction of access roads will presumably have the effect of
causing large mammals to withdraw from the vicinity,or to be exposed
to predation by 'humans.It is probable that the magnitude of the
movement away from disturbance is related to the seasonal home range
size of the individual animal,those with larger home range sizes
moving farthest.Data now being obtained on radio-collared
individuals will be helpful for the development of analyses of this
avoidance phenomenon.
4.1.4 -Transmission Facilities
The effects due to construction,projected for access road above also
pertain to transmission corridors.In both cases the lineal nature of
the disturbance insures that it will cross the home ranges of a large
number of individuals.
4.2 -Operation Impacts
4.2.1 -Watana Dam and Reservoir
The seasonal pattern of filling and drawdown will affect the formation
of ice-shelves in winter and their persistence in early spring.The
probable consequences of this for the caribou that are now thought to
cross the Susitna River within the area of the projected impoundment
have been considered by Hanscomb and Ostercamp (1980).These authors
point out that the projected lowering of the impoundment level (based
on the Corp of Engineers plan)during the winter will be:December-
10 1
;January -30 1
;February -15 1
;March -15 1
;April -10 1
;in May
the water rises 20 1
•They hypothesize a late April -early May
movement by the caribou toward their traditional calving grounds that
would necessitate a crossing of the drawn-down reservoir,with its
shelves and blocks of ice.They go on to say (pp.6-8):
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"We suggest that an ice-covered shore that is steep,
contains cracks,or has the potential for caving under
the weight of caribou,may present a serious obstacle to
their crossing the reservoir .
. . . .Realistic assessment of the effects of ice
shelving requires consideration of both caribou behavior
and ice conditions.With regard to ice conditions,the
greatest need is for a realistic model of the formation,
growth,and decay of the reservoir ice cover.Some
questions that should be addressed are:What are the
shore conditions or slope values that may cause the
settling ice cover to break,leaving cracks in which
caribou could be injured or possibly trapped?What is
the timing of this settling,cracking,and snow-cover
development that might mask the cracks?The thickness of
the settling ice cover will increase through the winter
but what will the thickness distribution be?Will the
wind keep the ice clear of snow?What are the maximum
slopes of clear ice and snow-covered ice that the caribou
can negotiate?How long will the ice-shelves remain
after breakup,and will caribou be forced to negotiate
melting (wet)ice shelves?"
"During the spring caribou migration,the reservoir
may still be frozen in the Jay Creek area,where the
caribou will be coming from the north down a slope
between 40-60%slope.Probably the only problems the
caribou would have getting down this shore would be
falling into cracks formed as the ice sheets settle or
breaking through the areas where the ice has bridged the
gaps.The south bank has a slope that varies from 109%
to 9%,with much of the shore between 30-60%slope,so it
is possible the caribou would have trouble climbing out
on the south side."
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liThe breakup dates of Jay and Kosina Creeks would
also be important.If these two creeks break up before
the caribou try to cross,there could be water flowing on
top of the reservoir ice,and melted areas formed at the
mouths of the creeks.An overflow,by itself,would
probably cause no problems unless it cut a channel
through the ice.Then the caribou might have trouble
climbing out on the floating ice cover after swimming or
walking."
"In the Oshetna River area these same questions need
to be answered,but the situation is a little different.
The slope on the north shore varies from 53.8%to 6.8%and
on the south shore from 35.9%to 6.8%,so both shores have
a more gradual slope than do those at Jay Creek.This
area may be affected by the breakup of the Tyone River as
well as the Oshetna River.For 3.7 miles (6 km)upstream
of the Oshetna River,the draw-down of the reservoir may
1eave an ice sheet on the ri ver bed and flood pl ai n.When
the Tyone River breaks up,water will be flowing into this
ice-covered area.The actual effect is unknown but there
could be ice jams and/or ice chunks floating in the area
which would make it difficult or impossible for caribou to
cross."
"In conclusion,it seems likely that the reservoir
will cause the caribou some problems,but the seriousness
of the problems cannot be realistically assessed until
more information has been gathered on caribou behavior
and on the ice conditions in the reservoir."
Although the ice conditions and caribou response discussed by
Hanscomb and Ostercamp are as yet little understood,there is
some knowledge available on the general needs and movements of
caribou in the study region.According to Kenneth Pitcher,who
has been studying these caribou most recently,it is apparent
that impoundment resulting from construction of the proposed
106
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Watana dam would intersect a major migratory route of the
Nelchina caribou herd.During the initial 8 months of the
current study only moderate use of this migratory corridor has
occurred by radio-collared caribou (and presumably by all
Nelchina caribou).Four radio-collared animals have crossed the
proposed impoundment area a total of seven times.Fi ve of the
crossings were north to south while two were south to north.
Historical reviews,however,indicate movements of virtually the
entire female-calf segment of the herd across the proposed
impoundment area in many years.During most years between 1950
and 1973,all or many of the females crossed from the calving
grounds to summer in the greater Deadman-Butte Lakes area (Skoog
1968,Hemming 1971,Bos 1974).Varying proportions of the herd
have wintered in upper Nenana-Susitna drainages in nearly all
years.Between 1957 and 1964 this area was the major wintering
area (Hemming 1971).Spring migration routes during those years
would have undoubtedly crossed the impoundment area.
large scale movements of caribou across the proposed impoundment
area have not been recorded since about 1976 (Eide pers.comm.).
However,based on past movement patterns and the quantity of good
habitat available in the upper Nenana-Susitna area [Skoog (1968)
considered some of this area the most important habitat for
year-round use in the Nelchina Range]it seems inevitable that
caribou will again use the area in large numbers.Movements to
and from the calving grounds will again result in many caribou
crossing the Susitna River in the area of the proposed Watana
impoundment.
A possible reaction to the impoundment by caribou is complete
avoidance and refusal to even attempt crossing.Another possible
reaction would be avoidance by some components of the herd and
attempted crossing by other segments.Cameron et al.(1979)
documented avoidance of the trans-Alaska pipeline corridor by
females and calves during summer.They also suggested avoidance
107
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by 1arge groups,group fragmentat i on and/or decreased group
coalescence near the pipeline corridor.Should animals attempt
to cross the impoundment,spring migration would appear to pose
the most serious problems.Pregnant females are often in the
poorest conditions of the annual cycle at this time (Skoog 1968)
and migratory barriers which normally could be easily
circumvented could become sources of mortality.Klein (1971)
suggested that when animals are in poor physical condition
seasonal migrations are easily disrupted.The potential for
injury or death to migrating caribou appears greater in spring
than during other periods.Skoog (1968)mentioned several
instances of injuries and death resulting from falls on or
through ice.Both Klein (1971)and Vilmo (1975)mention ice
shelving as a mortality factor of reindeer on reservoirs in
Scandinavia.Spring breakup would probably occur during the
migration,in many years posing additional hazards such as
ice floes,overflow and wet ice shelves.
Crossings during summer and fall when the reservoir would be ice
free appear to pose considerably less hazard.Caribou are
excellent swimmers and are known to cross much larger bodies of
water than the proposed impoundment (Skoog 1968).Young calves
might have problems with this distance if migrations occurred
shortly after calving.Water crossings have been reported as
mortality factors but usually involved rivers rather than more
placid bodies of water such as a reservoir (Skoog 1968).
It seems likely that the Watana impoundment would tend to isolate
the northwestern portion of the Nelchina range (an area of about
4,000 mi 2 ).Historically this area has been heavily used as
both summer and winter range by Nelchina caribou.
108
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The proximity of the Nelchina calving grounds to the proposed
Watana impoundments is of concern.According to Skoog (1968)the
calving ground is the "focal point"of a caribou herd.The
Nelchina herd has shown nearly complete fidelity to its calving
ground since records were available in about 1950.The calving
grounds are in one of the most remote and inaccessible regions
within the Nelchina range.Developments of the Susitna
Hydroelectric Project would change this.Expanded human access
and activity,which have been shown to adversely impact caribou
use of calving areas,would 1ikely occur.Cameron et al.(1979)
documented abandonment of a portion of the calving grounds of the
central Arctic herd concurrent with development of the Prudhoe
Bay oil fields.
Bergerud (1978)presents a somewhat different view and suggests
that caribou are quite adaptable and will adjust to human
construction and development.He states that the impacts of
human development and harassment have been overstated and no good
evidence is available indicating that development has caused
abandonment of ranges.However,he does state that calving areas
may be an exception and should be protected from both development
and disturbance.
Another hypothetical interaction between the presence of the
impoundment and the associ ated biota is the possibi 1ity that the
impounded water will act as a heat sink to the extent that early
snows will fall as rain on the reservoir and its shores.
Depending on the magnitude of this effect,and the timing of
winter snowfall,it is possible.that there will be a shallow-snow
zone around the reservoir.This could be of significant benefit
to moose,both because of a greater availability of forage and
because of reduced wolf predation.
109
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Conversely,the reservoir should be colder than the ambient
temperature in the spring,and so could have a delaying effect on
the phenological development of nearby plant communities.This
could reduce the amount of early spring forage available for
newly emerged brown and black bears,as well as over-wintering
moose.
4.2.2 -Devil Canyon Dam and Reservoir
This impoundment does not appear to intercept major caribou
movements.Increased human activity,as with the Watana dam and
reservoir may be a source of impact on wildlife in the area,for
example,influencing movement of brown bears to the Prairie Creek
salmon run.
4.2.3 -Access Road
Development of access corridors such as roads would probably have
negative impacts on Nelchina caribou.An access route through
the Deadman,Watana,Butte creek drainages to the Denali Highway
would traverse a major migratory route through prime caribou
habitat.Roads and railroads have been implicated in obstructing
movements af caribou and reindeer (Klein 1971,Vilmo 1975,
Cameron et al.1979).Nelchina caribou do continue to cross the
Richardson Highway,often in large numbers,and have done so
during many years since about 1960 (Hemming 1971).Several
studies (Miller and Gunn 1979,Calef et al.1976)have recorded
responses of caribou to aircraft disturbance and speculated on
deleterious impacts.Cows and calves were most responsive to
disturbance (Miller and Gunn 1979).Caribou showed increased
sensitivity during the rut and calving (Calef et al.1976).
110
Data on the deleterious effects of roads pertain mostly to
caribou because of the past interest in and studies of the Alaska
pipeline.But the other species of big game will also be
affected.From studies of big game in national parks,where
there is no hunting,and outside,where hunting is allowed,it
seems clear that animals outside act as though they associate the
sound of automobiles with disturbance,and keep clear of
travelled roads.This has the effect of reducing the habitat
available to them by the area from which they withdraw.In
addition,access roads facilitate the penetration of hunters in
larger numbers into regions hitherto inaccessible,further
increasing disturbance as well as mortality.
4.2.4 -Transmission Facilities
Electrical transmission lines have been reported to disrupt
movements of reindeer in Scandinavia (Klein 1971,Vilmo 1975)
because of associated noises (hum)and because they are foreign
objects in otherwise familiar surroundings.If electrical
transmission lines are downstream from the proposed Watana dam
site they should have little impact on caribou as long as they
are routed near the rlver.Few cari"bou occur in this area.
Other big game animals,however,occur in the downstream regions.
Their probable reaction to a noisy power line is not yet known ..
Other impacts,both positive and negative,may occur along the
transmission line route depending upon the extent of vegetation
clearing required,and also the changes in habitat types.
4.2.5 -Downstream Flow Regime
Since moose forage,particularly,is associated with the riparian
areas frequently disturbed by fluviatile processes,it would be
expected that a major change in downstream flow patterns would
influence downstream plant communities and,through them,
downstream moose populations.
111
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5 -MITIGATION
There appear to be three general ways that the impact of the proposed
project could be reduced or mitigated:control of human activity;
siting of routes and work-areas;and plant cOlT1l1unity management.
5.1 -Control of Human Activity
At present,the wildlife populations inhabiting the Susitna basin seem
to be minimally influenced by contact with humans.The proposed
project would bring much more human activity to the study area,with
some inevitable detrimental effect.But this effect will be least if
any human activity not essential to the project is kept to a minimum .
5.2 -Siting
Preliminary studies of all wildlife populations have shown patterns of
habitat preference.While it is still too early to identify all the
most valuable parts of the overall landscape for the various big game
species,it is reasonable to expect that analyses of seasonal habitat
use will demonstrate that some landscape units are more valuable than
others,seasonally,for most or all big game species.Assuming that
such information becomes available,it should be possible to take it
into consideration in the siting of routes and work..,areas ,wherever a
range of choices exists.
5.3 -Plant Community Management
The possible arenas for plant community management appear to exist,one
hypothetical,as yet,and the other obvious.The hypothetical
opportunity lies around the shores of the impoundments,and will exist
112
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if the presence of the impoundment creates a shallow-snow zone around
the shore.Then this zone could be considered for enhancement as
wildlife habitat.
The more evident opportunity lies downstream,where many opportunities
to manage plants for the benefit of big game,particularly moose,
exist.It would seem worthwhile to analyze the population ecology of
the downstream moose in greater detail than has been possible to date,
so as to identify the plant species and landscape units that would give
the best return on an investment in habitat enhancement.Further,the
secondary impacts of habitat enhancement measures on non-target plant
and animal species should be assessed as part of the study of habitat
management feasibility.
113
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128
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129
......,
7 -AUTHORITIES CONTACTED
Throughout 1980,there was close coordination among members of the
ADF&G Susitna Project investigations,TES,and TESl s big game
consultant,R.Taber.In addition,the following were contacted by TES
in relation to the big game studies.
Susitna Hydroelectric Project Steering Committee
Anchorage,AK.
-July 17,1980:presentation by TES staff of entire
environmental program.
-December 23,1980;TES response to Steering Committee comments
on Big Game Impact Assessment and Mitigation Plan Procedures
Manual .
130