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HomeMy WebLinkAboutAPA2925FEDERAL ENERGY'REGULATORY COMMISSION PROJECT No.7114 . FINAL REPORT OCTOBER 1985 DOCUMENT No.2925 FURBEARER STUDIES SPRING 1985:BEAVER Alaska Power Authority CONTRACT TO OO~~=[g[ID~@OO TNA J01NT VENTURE SUSITNA HYDROELECTRIC PROJECT b=a&~~&0 ~(ID&®©@ SUSITNA JOINT VENTURE 711 H STREET Alaska Department of Fish and Game 333 Raspberry Road Anchorage,Alask 99502 Attention:Mr.Carl M.Yanagawa ANCHORAGE,ALASKA 99501 TE L,(907)272 5585 December 16,1985 4.3.3.5/1.17.4.2 Subject:Susitna Hydroelectric Project Document TransmittaL Dear Mr.Yanagawa: Enclosed Eor your use and files is one copy of the LGL final report entitled "Furbearer Studies;Spring 1985:Beaver"(Document No.2925). Very truly yours, t4--- Randy Fairbanks Terrestrial Group Leader klk Enc:as noted ce w/o Ene: P.Lambert,HE J.Thrall,HE ALASKA DEPT.OF FISH &GAME DEC 18 1985 REG!ON II HAB/TAT DIVISION 223061/12 ,~ "'""I .... .- SOSITNA HYDROELECTRIC PROJECT FORBEARER STODIES SPRING 1985:BEAVER Report by LGL ALASKA RESEARCH ASSOCIATES James D.Waolington Robert H.Pollard and ARKANSAS GAME &FISH COMMISSION Phil ip S.Gipson Under Contract to Harza-Ebasco Susitna Joint Venture Prepared for Alaska Power Authority Document No.2925 Susitna File No.4.3.3.2 -rK I L.t (,),5 ,S~ F'&.1: no.~4~5 Final Report October 1985 ARLIS Alaska Resources Library &InfonnatlOn Services At\nchorage.Alaska - ..... N6TICE ANY QUESTIONS OR COMMENTS CONCERNING THIS REPORT SHOULD BE DIRECTED TO THE ALASKA POWER AUTHORITY SUSITNA PROJECT OFFICE ARLIS Alaska Resources Library &InformatIon Servlce~. Anchorage,Alaska - INTRODUCTION The beaver (Castor canadensis)was selected as the key furbearer species for study to predict impacts of the Susitna Hydroelectric Proj ect downstream from the proposed impoundments.There were three reasons for selecting beaver: 1"Beaver are tied directly to the aquatic system,and changes in water depths,flow rates,water temperatures,a.nd ice conditions will be reflected in changes in beaver distribution and abundance. .... I 2 . Beaver are economically and ecologically important. - -, 3.Reliable and practical techniques exist for censusing beaver populations and monitoring their use of habitats. This r,eport summarizes surveys conducted for beaver activity during spring 1985 and builds upon three previous reports which present the results of earlier furbea:r:er studies (Gipson et a1.1982, 1984,Woolington et a1.1984).These surveys have focused on determining numbers of beaver occurring along the Susitna River,and determining how beaver use both aquatic and adj acent terrestrial habitats.Monitoring numbers and distribution of beaver and other furbearers on a long-term basis is necessary to help understand the population dynamics and life requirements of these species relative to hydrologic conditions,so that project-related effects on furbearers can be predicted. The spring 1985 surveys were conducted to determine overwinter survival of beaver colonies located in October 1984 (Woolington et al.1984).Determination of oVlarwinter survival is essential if the effects on beaver colonies of naturally occurring river flooding and ice-scour during spring breakup are to be ascertained.Information from these and other surveys can then be used to assist in predicting responses of beaver and other furbearers to downstream changes expected to result from the project. STUDY AREA The study area is the floodplain of the Susitna River between Devil Canyon and Talkeetna in southcentral Alaska (Fig.1).The biotic communities,weather and physiography are discussed in Alaska Power Authority (1983).Surveys for signs of beaver activity were restricted to within 0.5 mi.of either side of the Susitna River. METHODS The survival of individual colonies of beaver through the winter may be assessed shortly before spring breakup by examining the area around identified lodges and bank dlens where food caches were located the previous autumn.During late April and early Hay,beaver along the Susitna River usually begin foraging above the ice around their colony sites.Emergence holes,where beaver dig out from beneath the ice,and fresh,muddy tracks on the snow or ice near the lodge indicate that at least some.beaver of a colony survived the winter (Gipson et a1.1984).However,the identified colonies must be examined again after spring breakup,because conditions at breakup may destroy colonies that have survived through winter up to that point. SUS2/05 1 10/30/85 R,VER miles 0 5 10 !:1 ,r 0 5 10 15 kilometers •..".Q.,.,-., Figure 1.Susitna River bebween Devil Canyon and Talkeetna. ..-, - In spring 1985,three helicopter surveys were made along the Susitna River between Devil Canyon and Talkeetna to examine known lodge and bank den locations for evidence of recent beaver activity.The colony locations were previously identified during beaver cache surveys made in October 1984 (Woolington et al. 1984).To assess the overwinter survival of colonies prior to spring breakup of the Susitna River,two·pre-breakup surveys were made on April 23 and May 3, 1985.During the third survey,flown on June 11,1985,the colony sites were re-exmnined to determine which colonies survived breakup and therefore success- fully overwintered. RESULTS Only 10 of the 45 colony sites originally located in October 1984 showed evidenl:e of beaver activity during the April 23 survey (Tables 1 and 2). Evidenl:e of recent beaver activity was observed at 21 of the 45 colony sites during the May 3 survey.During the June 11 post-breakup survey,evidence of recent beaver activity was observed at 23 colony sites,and no activity was evident at 19 sites.Three colony sites were classified as unknown (activity not determined). Colony sites where no evidence of beaver activity could be determined during the spring surveys are assumed not to have survived the winter or breakup.It is likely that most beaver in unsuccessful colonies died. Thirteen beaver colonies were located in mainstem habitat in October 1984.Of these,beaver from at least five colonies successfully overwintered and survived breakup in spring 1985.·Seven other colony sites were eroded away during breakup.The status of one colony in mainstem habitat was not determined. Four colonies were located in side channel habitats in October 1984.At least til10 successfully overwintered and survived breakup,one colony showed no evidence of activity during the spring surveys,and the site of another colony was eroded away spring breakup. Fourteen colonies ·were located in Sl.ue sloughs in October 1984.Of these, beaver successfully overwintered and survived breakup at eight colonies,four colony sites showed no evidence of activity,and the status of two colonies in side sloughs could not be determined. Fourteen beaver colonies were located in upland sloughs in October 1984.Beaver successfully overwintered and survived at eight of these colony sites.Four of the colony sites showed no evidence of activity in spring 1985 and apparently did not survive the winter.The status of two colonies could not be determined. Severa.l colony sites appeared active in either the April 23 or the May 3 surveys,but not during the June 11 survey.Of these,cne in mainstem habitat and another in a side slough were eroded away during the floods associated with spring breakup.At one upland slough and one side slough occupied by beaver colonies,the dams were broken open and the ponds partially drained after the initial determination of overwinter survival.The fate of the beaver in these two colonies is unknown. SUS2/05 3 10/30/85 ~­, - ",.., ~- - DISCUSSION The first survey conducted in spring 1985 (April 23)was too early in the season.Beaver activity was observed at very few of the colony sites.However, as shown by the later surveys,beaver successfully overwintered at more colonies than indicated. Of the 24 colonies where no evidence of activity was observed during the May 3 survey l'8 appeared to be occupied during the June 11 survey,indicating that pre-bre!akup surveys show the minimum numbers of colonies that successfully overwinter.Of the 19 colonies with no evidence of activity on the June 11 survey"evidence of activity was noted at three colonies during the May 3 survey"indicating beaver had over-wintered at those sites,but were not present after breakup. All evidence of caches or lodges at 10 colony sites was removed (by ice scour or erosion)during spring breakup.The likelihood of survival by beaver at those sites is low (Hakala 1952,Gipson et a1.1984).Though colonies established along mainstem river habitat appeared to be the most vulnerable (7 of the 10 that Wiare affected by ice),ice and water diverted by ice jams destroyed lodges of two colonies in side sloughs,and one colony in a side channel. Results from this survey indicate overwinter survival of beaver colonies cannot be absolutely determined by a single survey occurring either before or after breakup.During the May 3 survey,evidence of activity at several colony sites was not observed,but during the June 11 survey,occupation at those sites was determined.Conversely,several colony sites determi,ned to be occupied during the M~r 3 survey were destroyed during breakup,and showed no evidence of beaver activity.Determination of beaver activity at colony sites both before and after spring breakup is essential if the effects of river flooding and ice-scour on the beaver colonies are to be accurately ascertained. Summary Based on the number of active colony sites found during the June 11 survey,at 'least 23 of the 45 beaver colonies located in October 1984 successfully over- wintered and survived spring 1985 breakup along the Susitna River between Devil Canyon and Talkeetna.Ten colony sites were eroded away during spring breakup and nine other colony sites did not show evidence of beaver activity in the spring.The survival rate of beaver colonies was greatest in side sloughs and upland sloughs (each with 8 of 14),followed by side channels (2 of 4)and mainstem (5 of 13). SUS2/05 4 10/30/85 TABLE l.Results of spring 1985 surveys of beaver colony sites on the Susitna River,between Devil Canyon and Talkeetna.A =Evidence of recent beaver activity,N =No evidence of recent beaver activity,E =Site eroded away,U =Unable to determine. ..~ Colony No.1 River Habitat 2 April 23 May 3 June 11 ,~84-1 mainstem A A A 84-2 side slough A A A 11l>~ 84-3 side .slough A A A 84-4 upland slough N A A 84-5 side slough N N N 84-6 upland slough N A N3 84-7 upland slough N N N 84-8 side slough N N4 N5 84-9 mainstem N N N/E 84-10 upland slough N A A 84-11 side slough N N A 84-12 side slough N A A 84-·13 mainstem N N N/E 84-·14 side channel N N A- 84--15 mainstem A A A ....84--16 side slough N A A 84--17 mainstem N N N/E ~ N384--18 side slough A N/E 84--19 side slough N N A 84--20 side channel N N N6 84··21 side slough N A A -SUS2/05 5 10/30/85 Table 1 (cant.) Colony No.1 River Habitat 2 April 23 May 3 June 11 84-22 side slough N A A 84-23 rnainstem N A U 84-24 upland slough N A A 84-25 upland slough N A U 84-26 upland slough N A A ~ 84-27 mainstem N N A 84-28 side slough N N N 84-,29 mainstem N N N/E 84-,30 mainstem N N A 84-·31 mains tern N A A 84-·32 side channel N A A 84--33 upland slough A A u 84--34 upland slough A A A 84--35 upland slough N N A 84--36 upland slough N N N 3 84··37 upland slough N N N 84··38 upland slough A N A 84··39 mainstem N N N/E-84··40 upland slough A A A 84-·41 mainstem N N N/E ""'" 84--42 side channel N N N/E 84--43 rnainstem A A N/E SUS2!05 6 10/30/85 Table 1 (cont.) Colony No.1 River Habitat 2 April 23 May 3 June 11 84-j~4 side slough N A N/E 84-,~5 side slough N N N5 A =10 A =21 A 23 N =35 N =24 N 19 U 3 E =10 .- ..... 1 2 3 4 5 6 Colony numbers from Woolington et al.(1984). River habitat classification by Alaska Department of Fish and Game Aquatic Study Team (ADF&G 1983). Dam broken open and slough partially drained. Slough frozen to bottom. Food cache intact.No evidence of beaver feeding on cache through winter. Hank exposed because of low water . SUS2/05 7 ---------------- 10/30/85 TABLE 2.Results of spring 1985 surveys of beaver colony sites on the Susitna River,between Devil Canyon and Talkeetna.A =Evidence of recent beaver activity,N =No evidence of recent beaver activity,E =Site eroded away,U =Unable to determine. r - .- , Results of Survl:L- A N N/:E U Mainstem 5 7 1 13 River Habitat Side Channel Side Slough Upland Slough 2 8 8 1 4 4 1 2 2 4 14 14 SUS2/05 8 10/30/85 '-----'---------....._--------------------------- Literature Cited Alaska Department Fish &Game.1983.Susitna Hydroelectric Project Studies. Phase II.Basic Data Report.Vol.IV:Aquatic Habitat and Instream Flow Studies,1982.Parts I and II.Prepared for Alaska Power Authority. Alaska Department of Fish and Game,Anchorage.367 Pl'. resources. License Energy Fish,wildlife,and botanical Susitna Hydroelectric Proj ect. Alaska Power Authority to Federal Alaska Power Authority.1983. Exhibit E,Ch.3.In: application submitted by RE~gulatory Comm.,Anchorage.-- -Gipson,P.S.,S.W.Buskirk,and T.W.Hobgood.1982.Susitna Hydroelectric Plroj ect.Furbearer Studies,Phase I Final Report.Prepared for Alaska Power Authority.Alaska Coop.Wildlife Research Unit,Univ.of Alaska, Fairbanks.81 Pl'. Gipson,P.S.,S.W.Buskirk,T.W.Hobgood,and J.D.Woolington.1984.Susitna Hydroelectric Project.Furbearer Studies,Phase I Report Update.Prepared for Harza-Ebasco Susitna Joint Venture.Alaska Coop.Wildl.Res.Unit, Ultliv.of Alaska.,Fairbanks.100 Pl'. Hakala,J.B.1952.The life history and general ecology of the beaver (Castor canadensis)in interior Alaska.M.S.Thesis.Univ.of Alaska,Fairbanks. 181 Pl'. Woolington,J.D.,P.S.Gipson,and D.Volsen.1984.Susitna Hydroelectric -Project.Furbearer studies,Fall 1984:Beaver.Prepared for Harza-Ebasco Susitna Joint Venture.LGL Alaska Research Associates,Inc.and Alaska Coop.Wildl.Res.Unit,Univ.of Alaska,Fairbanks.30 Pl'. sus2/05 9 10/30/85 ....Appendix A.Locations and habitat designation of beaver food caches along the Susitna River,between Devil Canyon and Talkeetna.October 4,1984 (From:Woolington et al.1984). ~ Site No.Characteristics .-84-1 Location T31N,R2W,Sec .10,NW\of SW\ north side of river River mile 139.5 Habitat mainstem 84-2 Location T31N,R2W.Sec.9,NE\of SE\ north side of river River mile 139.4.Slough 18 Habitat side slough .-84-3 Location T31N,R2W,Sec •9,NE\of SE\ north side of river River mile 139.4.Slough 18 ,....~Habitat side slough 84-4 Location T31N,R2W.Sec.8.SE\of SE\ north side of river -"139.aRivermile Habitat upland slough 84-5 Location T31N.R2W,Sec.17.NW\of NE\ northwest side of river River mile 137.4,Slough 15 Habitat side slough 84:"'6 Location T31N,R2v.l,Sec.17,SE\of NW~ northwest side of river ~River mile 137.2,Slough 15 Habitat upland slough 84-7 Location T31N,R2W,Sec.19,NW\of NE\ northwest side of river River mile 136.4,Slough 14-Habitat upland slough 84-8 Location T31N,R2W,Sec.19,SE\of SE\ east side of river River mile 135.7,Slough 11 Habitat side slough .-84-9 Location T31N.R2W,Sec •19,SW~of SE\ west side of river River mi.le 135.5 Habitat mainstem SUS2/05 .10 10/30/85 ,- Site No.Characteristics 84-10 Location T31N,R2W,Sec.25,SE~of NE~ west side of river,-River mile 134.0,Slough 10 Habitat upland slough 84-11 Location T31N,R3W,Sec.36,NW~of NE~ southeast of river River mile 133.3,Slough 9A Habitat side slough 8.4-12 Location T31N,R3W,Sec.36,NW~of SE~ east side of river,...,River mile 133.4,Slough 9A Habitat side slough 84-13 Location T31N,R3W,Sec.36,SW~of SW~ northwest side of river River mile 132.8 Habitat mainstem F 84-14 Location T30N,R3W,Sec.2,SW-l;of NE~ northwest side of island,on northwest side of river ~River mile 132.0 Habitat side channel ~84-15 Location T30N,R3W,Sec.9,SW~of NE~ dmmstream end of island River mile 129.8 Habitat mainstem 84-16 Location T30N,R3W,Sec.9,NW~of SW~ east side of river-River mile 129.3.Slough 9B Habitat side slough 84-17 Location T30N,R3W,Sec.20,NW~of NE~ mainstem side of island,on west side of river River mile 127.4 Habitat mainstem 84-18 Location T30N,R3W,Sec.30,NE~of NE~ southeast of river River mile 126.0,Slough 8A Habitat side slough 84-19 Location T30N,R3W,Sec.30,g E!,;0 f NW!t; southeast of river River mile 125.7 Habitat side slough SUS2/05 11 10/30/85 Site No.Characteristics 84-20 Location T30N.R3W.Sec.25.SE~of NE~ downstream end of island .-River mile 125.0 Habitat side channel ~84-21 Location T30N,R3W,Sec.30,NW~of NW~ island on east side of river River mile 125.8 Habitat side slough 84-22 Location T26N.R5W,Sec.13,SW~of SW~ west of river r-~River mile 98.0,Billion slough Habitat side slough 84-23 Location T26N.R5W,Sec.24.N~of SW~ east side of river River mile 98.0 Habitat mainstem 84-24 Location T26N.R5W.Sec.23.NE~of NE~ east of river r:'l\lllVl River mile 98.0 Habitat upland slough 84-25 Location T26N.R5W,Sec.13.SW~of SW~ east of river River mile 98.0 Habitat upland slough~ 84-26 Location T26N,R5W,Sec.14,SE~of NE~ east side of river River mile 99.4 Habitat upland slough 84-27 Location T26N.R5W.Sec.14.swt-z;of SE~ east side of river River mile 98.5 Habitat mainstem 84-28 Location T26N,R5W.Sec.14.NE~of NW~ west side of river River mile 99.0 HabHat side slough .'~84-29 Location T26N.R5W.Sec .11.NE~of NW~ mainstem side of island on east side of river River mile 100.4 Habitat mainstem SUS2/05 12 10/30/85 """Site No.Characteristics 84-30 Location T26N,R5W,Sec.11,SE~of SE~ island on east side of river River mile 99.8 Habitat mainstem 84-31 Location T26N,R5W,Sec.11,SE~of SE~ island on east side of river River mile 99.8 Habitat mainstem 84-32 Location T26N,R5W,Sec.2,SE~of SW~ east side of river ~River mile 100.6,Slough 2 Habitat side channel ~84-33 Location T27N,R5W,Sec.35,NW~of SW\ west of river River mile 102,Slough 3A Habitat upland slough 84-34 Location T26N,R5W,Sec.25,SE\ofSE~ east of river ,~ River mile 102.9 Habitat upland slough 84-35 Location T27N,R5W,Sec.25,SE~of SE~ east of river River mile 102.9 r"'"Habitat upland slough 84-36 Location T27N,R5W,Sec.13,SW~of NW~ east of river River mile 105.6 Habitat upland slough 84-37 Location T27N,R5W,Sec.12,SE~of SW~ east of river River mile 106.2.-Habitat upland slough 84-38 Location T28N,R5W,Sec.36,SW~of NE~ west of river River mile 109.3 Habitat upland slough 84-39 Location T28N,R4W Sec.30,NW~of NW~ east of river River mile 110.5 ..-Habitat mainstem SUS2/05 13 10/30/85 Site No.Characteristics - .- 84-40 84-41 84-42 84-43 84-44 84-45 Location River mile Habitat Location River mile Habitat Location River mile Habitat Location River mile Habitat Location River mile Habitat Location River mile Habitat T28N,R4W,Sec.6,SE~of SW~ east of river 114.2,Slough 8 upland .slough T28N,R4W,Sec.6,NW~of SW~ downstream and of island in mid-channel 114.7 mainstem T29N,R4W,Sec.21,NW~of NE~ east side of island 119.0 side channel T29N,R4W,Sec.16,NE~of NE~ main channel side of large island on west side of river 120.1 mainstem T30N,R4W,Sec.35,SW~of SE~ east of river 122.6 side slough T30N,R4W,Sec.35,NE~of SE~ east of river 123.2 side slough SUS2/05 14 10/30/85