1170 U.S. Department of the Interior U.S. Geological Survey
Arctic Refuge Coastal Plain Terrestrial Wildlife Research Summaries U.S. Department of Interior U.S. Geological Survey
Arctic Refuge Coastal Plain Terrestrial Wildlife Research Summaries
Edited by: D. C. Douglas, U.S. Geological Survey, Alaska Science Center, Anchorage, Alaska P. E. Reynolds, U.S. Fish and Wildlife Service, Arclic National Wildlife Refuge, Fairbanks, Alaska E. B. Rhode, Expression, Anchorage, Alaska
Biological Science Report USGS/B RD/BSR·2002·0001 U.S. Department of the Interior Gale A. Norton, Secretary
U.S. Geological Survey Charles G. Groat, Director
U.S. Geological Survey, Reston, Virginia: 2002
Any use of trade, product, Of firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government.
Copks of this publication arc available from the National 'Ii:chnical Information Service, 5285 Port Royal Road, Springfield, Virginia 22161 (I_HOO·553_6847 or 703-487 -1650). Copks also arc available to registatd users froill the Defense Technical In[onJlation Center, Alln.: Help Di:sk. 8725 Kingman Road, Suile 0944, Fon Belvoir, Virginia 22060-6218 (1-800-225-3842 or 703-767-9050). Digital copies of this publication C:l1l be obtained on the Internel at hllp:l/;ll;l.~ka.usgs.go\'.
('illllioll .'xamp!;':
Griffith. B., D. C. Douglas, N. E. Walsh, D, D. Young. T. R. McCabe, D. E. Rlls.~cll. R. G. White, R. I). Cmwwn, and K. R. WhitteJ}. 2002. The Porcupine caribou herd. Pages 8-37 in D. C. Douglas. P. E. Reynolds, and E. B. Rhode. editors. Arctic Refuge coaslaJ plain terrestrial wildlife research sUJlJmaries. U. S. Geological Survey. Biological RcsOIJrces Division, Biological Sciencc Report USGS/BRDI BSR-2002-0001.
ii Preface
In 1980, when the U.S. Congress enacted the Alaska National Interest Llnds Conservation Act (ANILCA), it also mandated a study of the coastal plain of the Arctic N~lliollal Wildlife Refuge. Section 1002 of ANILCA slated lha! a comprehensive invelltory of fish and wildlife resources would be conducted on 1.5 million acres of dIe Arctic Refuge coastal plain (1002 Area). Potential pctrolcUIll reserves in the 1002 Area were also (0 be evaluated from surface geological sludies and seismic exploration .~urvcys. Results of these studies and recommendations for [mllee management of the Arctic Refuge coaS!3[ plain were to be prepared in a report to Congress. In 1987, the Departlllent of Interior published the Arctic National Wildlife Rcfugt', Alaska, CDanal Plain RNDurce Arsess!lwn! - Report and RCCDJIllllt'/ldlltirJ/l (0 tl/l' Congress o[tl/l' United StaleS (lmi Final Elll'imnmclltal impact SWftmtlll. This report to Congress identified the potclIlial for oil and gas production (updated* most recently by Ihe U,S, Geological Survey in 200 I), described the biological resources, and cvaluated the potential adverse effects to fish and wildlife resources. The 1987 report analyzed the Jlotelltial cnvironmental consequences of five management altemOltives for tlle coastal plain, nlllging frOIll wilderness designation to opening the entire area to IC3se for oil and gas developmellt. The report's summary recollllllended opening the 1002 Area to an orderly oil and gas leasing program, but cautioned that adverse cffect.~ to sO/l1e wildlife Jlopulations were possible. Congress did not act on this recoll\lllendation nor allY other alternativc for tlle 1002 Area, and scientists continued studies of kcy wildlife species and habitats on the coastal plain of thc Arctic Refuge and surrounding areas. This report contains updated summaries of those scientific investigations of caribou, muskoxen, predators (grizzly bears, wolves, golden eagles), polar bears, snow geese, and !heir wildlife habitats. Contributiolls to tllis report were made by scientists affiliated with the U.S. Geological Sun'ey; U.S. Fish and Wildlife Service; Alaska Departlllent of Fish and Game; Univcrsity of Alaska-Fairbanks; Canadian Wildlife Sen'ice; Yukon Department of Renewable Resources; and the Northwcst Terrilories Departmenl of Resources, Wildlife, and Economic De,'c!opmenl. Sections of the reJl0rt prcsclltillj,; ncw information on caribou and forage plants were peer-reviewed by thrce indcJlendent, non-affiliated scientists. The remaining sections sUlllmarize previously published peer-rcviewed scientific papcrs and wcre reviewed by a single independcllC scicntist. The U.S. Geological SlIn'cy :md thc U.S. Fish and Wildlife Servicc collaborated in the publication of this report.
:r U.S. Geological Survcy Fact Sheet FS-028-0l hup:1Igeology.cr.lls£s.g0vIpuh/fac t· .~hecIs/fs-002 ~ -0 II
iii
Contents Page Preface...... ,...... iii Authors' Addresses...... Scclioll 1. Introduction. . . Background.. .. Study ACI~a. 2 References...... 2 Section 2. Land Cover...... " Vegct,ltiorl 1\1 appillg of the Arctic Refuge Coa.'>tal PI ~lin.. .j References...... 6 Seelion 3. The Porcupine Caribou Herd...... 8 Data, Methods and Assumptions...... S NUlritiorta[ Irnponance of the Calving Ground II Habitat Trends During the SlIIdy Peliod... II Herd Dynamics and Delllogfilphy...... 13 Season",1 Distribution and I\lovell1ents...... 15 Foraging on the Calving Ground...... 20 Habitat Selection...... 21 Effects of Insect Harassment on Habitat Usc...... 24 Calf Performance in Relation to Habitat Usc...... 25 Factors Associated with Calf Sun'ival on the Calving Ground...... 25 Potl;ntial Effects of Dcvelopment on Junc Calf SurvivaL...... 28 Conclusions...... 32 Rcferences...... 34 Section 4. The C('lltral Ardic Caribou Herd . 38 Status of the Central Arctic Herd...... 39 Development-related Ch'lllges in Distribution...... 39 Body Condition and Reproductive PerfOnll;\llce.. .. 41 Ovcrview.. . 43 Referencc"'...... 44 Section 5. Forage Qualltit~' and Quality . . 46 Forage Comparisons Within and Outside the 1002 Area.. 47 References ,...... 50 Sectioll 6. Pr('c111tors...... 51 Prl:dator Distribulions...... 51 Factors Associated with Prl:dator Distributions 51 Rates of Prl:dation ".. 53 References...... 53 Section 7.l\1uskoxen...... 54 Dynamics and Rangc Expansion of a Re-cstablishl:d /l.llISkox POPU1:ltion.. .. 54 SC:lsonal Stratcgies of Muskoxl:n: Distribution, l-Iahit:\IS, and Activit}' Pattl:nls...... 56 Winter Habitat USl: of Muskoxen: Sp:llial Scales of Resource Selection...... 61 Sulllmary...... 62 Rdercllccs...... 63 Sectiun 8. Polar Bears...... 65 1>1ovcnlCnts and Population Dyn'llllics of Polar Ilears ,... 65 Reproductivl: Significancc of 1\lalcrnit}' Denning on Land 67 Refcl"l:nccs.. 69 Section 9. Snow Gccs~. 71 Sizl: and Distribution of Sllo\V Geese Populations 71 Snow Goose l-Iabitn!. Food. and Energy Rl'q\lir(~rnents... 71 Effect of l\li!ig,llion of I·hllnan Activitk, on Sno\\' Geesl: 73 Refl:rl:llCl:s... 74 Acknowlcdgclll('lltS , ,...... 75 Figures Nllmba Page 1.1. Geographic 1l13Jl of the Arctic Nation;"!] Wildlife Rduge. Alaska, USA, fwd surrounding areas 1
1.2. Geographic map of the 1002 Area of the coastal plain of the Arctic N:lIional Wildlifc Refuge, Alaska 3
2.1. L3nd-cover lIlap of the 1002 Area with corresponding vegdation class names, descriptions, and cklss codc.~, Arctic National Wildlife Refuge, Alaska...... 5
3,1. Land·cover classes on the Arctic Refuge coastal plain and eastward as generalized for cariboll studies...... 9
3.2. For the Porcupine caribou herd: anllual range, calving sites, and aggregate extent of calving, 1983- 2001. For the Central Arctic caribou herd: calving sites and extent of calving, 1980-1995 ...... 10 , 3.3. ivkan temperatures for 2 stations within the Porcupine caribou herd's aggregate extent of calving i, and 1 stalion within its winter range for a) June and lJ) winter, 1950-1995.. 12
3.4. I\fcdian Normalized Difference Vegetation Index (NDVI) Oil 21 June within the aggregate extent of calving for thc Porcupine caribou herd, 1983·2001...... 12
'i 3.5. Standardized values of the Arctic Oscillation (AO) for winter and standardized JlOJlUI;llion size of the Porcupine caribou herd, 1958-2001...... 12
3.6. I\Iedian NDVI at calving within the aggregate extent oft:alving of the Porcupine caribou herd for thc current year, and winter Arctic Oscillation index for the previolls calendar year, 1985-2001...... 13 • 3.7. Frequency of days with daytime temperatures above freezing in a) spring and b) fall, on transitional ranges of the Porcupine caribou herd during the increase and decrease phases of the herd 13
3.8. Size of the Porcupine caribou herd, 1972-200 J, l'stimated frolll aerial photo-cl'l1.'ill.ses by the Alaska Depal1rnent of Fish and Game...... 13
3.9. Rel:ltive post-calving herd size.s of the" Alaska barren-ground caribou herds, 1976-200 I...... 14
3.10. Reproductive e.~tiJl1ates for the Porcupine caribou herd, 1983-200 I: (l) parturition ratc of adull fcmales, /I) calf survival from bit1h through the last week of June, ;lI1d c) net calf production 14
3.1 I. DistribUlion of sate II itc-collared Porcupine caribou herd felllales during 7 time periods, 1985-1995 J6
3.12. Minimulil median daily movcment rate of panuriellt satdlite-collared females of the Porcupine caribou hcrd, 1985-1995...... , 17
3.13. Calving distributions of the Porcupine caribou herd, 1983-2001 . IS
3.1·1. Percellt ofrallio-collarl'd Porcupinc (ariboll herd females thaI (;llved in lh.: 1002 Ar~';t. 19RJ-2001 II)
3.15. )lerccllI of radio·collared Porcupine Ctrihou herd fem;tks lhat calved within tile 1002 Arl~a in rdatjrm to the median NDVI at calving within thl' aggregate extcnt of calving, 1985-2001.... 19
3.16. Porcupine carib\)lJ herd tI) diet cOll1pn.~iti()1l and II) median phenology of m;tjor foragL' itL'lllS, 19~n..... 20
3.17. Porcupine caribou herd ill diet composition and h) median phenology oflll 3.18. Annual conditions of srWWcover and veget:llion phenology derived from saId lite im;lgcry duri ng the calving period, 1985-2001, for the Porcupitw caribou 11l'rd 22 " Figures (continued) Number Page 3J 9, Average percent of area in low (,::; median) or high (> median) cla~se$ of a) daily rate of increase in the NDVI, b) NDVI at calving, and c) NDVr on 21 June for the aggregate extent of calving, anllu;l1 calving grounds. and concentrated calving areas of the Porcupine caribou herd, 1985·200I 23 3.20. Average percent of area in 4 exclusive Slloweovcr classes for the aggregate extent of calving, anllual calving grounds, and cOllCClIlratcd calving arca.~ of lhe Porcupine caribou herd, 1985-2001 ". 23 3.21. A\'l:ragc percell! of arca in 6 vegetation types for the aggregate ex lent of calving, annual calving grounds, and COllccrtlralcd c;llvillg arC;h of the Porcupine caribou htrd, 1985-200 I ...... 24 3.22. Estimated total int;lke of diemry nitrogcll from the ctlving ground for·1 Nonh American e;lribou herds.". 24 3.23. Daily weight gain of caribou calves of thc Porcupine herd. 1992·199·;, during 2 timc periods 25 3.24. Availability of6 vegetation types in the aggregate extent of calving f(lr the Porcupine cariboll herd and usc by radio-collared calves during 2 time periods .for 11) 1992. h) 1993, and c) 1994 26 3.25. l....kdian NDVI on 21 June within tlle Jnllual calving grounds of the Porcupine caribou herd and weights ofpartUrlellt female ehribOIl when captured withillthe annual calving ground 01\ 21 June. 1992-1994...... 26 3.26. Calf survival through June for the Porcupine caribou herd. 1985-2001, in relation t<) median NDVI on 21 June within the aggregate extent of calving.... . 27 3.27. Predicted calf survival through June for the Porcupine caribou had, 1985-2001, ill relation 10 Illcdi;ln NDVI 011 21 June withilllhc annual calving ground ;lnd to the proportion of calves born 011 the coastal plain physiographic zone whae prcdalOr dcnsity was lower than in the foothill-mountain zone 28 3.28. Estim;lted change in calf survival during June for the Porcupine caribou had, 1985-2001, as a function of the distance of displacemcllt of the aBllllal calving ground and associated conccntrated calving arca and calving sitc.~...... "...... ".. 31 3.29. Aggregate c'.xtent of annll;11 c,lI ving and aggrcgate exten! of concentrated calving for the Porcupine caribou herd, 1983·2001...... " " 33 4.1. Oil field infrastmcture in the Prudhoe Bay and Kilparuk !)('trolcUlll dcvelopment areas, Alaska, 1994.... 38 4.2. Photocellsus estimates of the Central Arctic <:aribou herd, 1978-2000, and net calf production based 011 observations of radio-collared adult females from 10 June through 15 August.. 39 4.3. Fractional changes in mean density of caribou from the Ccnlr;ll Arctic herd hetwcen prc-constl1lction (1978-1981) and post-constnJclion (1982·1987) periods for I-klll-diswnce intervab from thc Milne Point road system in the Kupamk petroleUlll dcvelopment area, Alaska.... . ,...... ,...... 39 4.'1. Ch;lllges in mean relative distribution of c;lribou from the Central Arctic herd in the KUp;lnJk petroleum developmcllt ,Irca, Alaska, during calving: 1979-1981, 1982-1986, and 19R7·1990 40 4.5. Decline in percent ;lbuIHlancc~ ofcariboll frolllthe ('L'lllr:il Arctic herd \\"('"t of the I\lilne POlut Road and changes in IOtal numbers ~)f c,lriboll observed north of the Spine Road, 1979-R7. -10 4.6. Helationship between llle:lJ1 density of caribou from the Central Arctic had and road density within preferred mgged terrain, Kllp:lmk PL~trok1Jlll del'c!l)]llllL'Jlt ;lre:l, Absk:l, 1987-llJ92... . ,11 4.7. Shifts ill CO/lf,:;cnlmled calving areas. Central Arctic carihou Ilerd, Alaska, 1980-1995... 41 VII Figures (continued) Nllmber Page 4.8. Logistic regressions of parturition ralt::, incidence of carly calving, and perinatal calf 5urviv::11 on ;\ulumn and SlImJlll'r body weights of female caribou, Central Arctic herd, 1987-1991...... 42 4.9. Changes in median NDV] on 21 1une for concentrated calving areas of the Celllf'l] Arctic caribou herd in the reference zOllc(rdativdy undisturbed) and treatment zone (active oil fields), 1985-1995 42 ·~.IO. l\kan body weights of !;lcl:lling and llonbcl:lling female caribou from the CCllIr:1l Arctic herd in summer and autumn ,...... 43 4.11. Disiriblllion~ of Ilbs~rv~d 5.1. 1\1 6.1. Distribution of a) goJd~n eagle n~st structures, h) wolf dellS, and c) grizzly bears ncar the calving grounds of the Porcupine caribou herd...... <" •••••• 52 7.1. Number of lllu..,koxell observed inlhel002 Area of the Arctic Refuge, 19S2-2001 54 7.2. Changes in r 7.3. Number of muskoxen killed or scavenged by grizzly bears from April 19H2through June 20tH in northeastern Alaska 55 7A. Range expansion of llluskoxcn in mixcd·.,ex groups in and near the Arctic Refuge, 1969-1993 57 7.5. Season 7.6. Locatiol1s of mixed-sex groups of muskoxen secn during wintcr and summer SUf\'eys in the Arctic Refuge, 1982-1999...... 59 7.7. SIlOW depth in mll.~knx feeding zones, adjacent zones, and nonadjacent zoncs in late winter. 1989 and 1990 OIl the cO;lslal plain of the Arctic Refuge...... 61 8.1. Numbers and relocation positions of satellite radio-collared Jlolar bears c 8.2. Number of pol:!!" hear dens located hy radio-telemetry in c;\ch of 3 substrates. 1981-1990 ".... 68 8.3. /l.latL'mal den ! SA. Distribution of lll;ltern;rl dens of radio-collared polar hears along the northern coast of Alaska and Canada, 19:-11-2001. . "...... 69 9.1. NII!l1ber.~ or lesser SIll)\\, gcese observed on the cO;lsl 9.2. Frequency of lise of 25-kll1~ cclls by lesser snow goose /locks on the coastal plain or tile Arctic Rd"ugc, Il)82-llJ93. . "...... 72 lJ.3. Rat!:s of lipill dcpllsition by lesser snow gee.~e during fall staging OJ} the Arctic Refuge 73 viii J Tables NI/mba Pagl: 2.1. Contingency table used to assess the accuracy of the land-cover map of the coastal plain of the Arctic National Wildlife Refuge. Alaska , " 6 2.2. Percent of each hmd-covCf class in the land-covCf lIlap of the coastal plain (If the Arctic Rdugc, and the percelit partitioned among various terrain Iypes...... 7 3.1. Number of cllving siles, !lumber of calving Sill'S in the concentrated calving arca (CCA), an.~a of CCA, ,\rca of annual calving ground (ACG). ralio of sizes ofCCA 10 ACG, and population size of the Porcupine caribou herd, 1983-2001... 19 4.1. Parturition status of 43 raJio· 5.l. I'vkdian phenological stages of major forage spccics in the Por 5.2. I'vledian biomass ,Illd pr:rCCl1t covcr of 4 major caribou foragc specics in the 5 most COllllllon vcgetationtypes 011 thc coastal plain during thc Porcupinc 5.3. i\ledian dcnsity, bioll1ass, and pcrccnt covcr of major forage sJlccics in the Porcupinc cariboll herd's traditional calving arca and potential displaccmcnt arca, 1990·1991.... . 48 5.4. Medianllutricllt and fiber concentrations of 2 major forage species ill different phonologic:ll stages in the Porcupine caribou herd's traditional caribou calving area and potential displacemellt area . 49 5.5. Distribution of vcgetation types in the caribou forage sludy area based on ,Hl illdependem sample of 756 systematically-located vcgetatjon plots 49 5.6. I'vfedian lllltricJH and fibcr cOIl 7.1. Numbcr of lllll.~k()xcn scen in diffcrent rcgions in northeastern Alaska, USA, aud northwestern Clllada in19S2-2000during prc·cal"ing sun'cys 58 lX Authors' Addresses Robert (Skip) Ambro..• Jan,t C. Jorg.nlon W.lttrT.Smlth USFWS Endangered Species USFWS Altlk: National WMlife Reto;e AJasi:a Department or Fl:!t11ltld GatM EcoIO\Ik:aI Services Field otrlCe-F a!ttlanks 101·12" Avenue, Room 236 1300 CoII&g1l Road 101-12" A~IlIlUtl, Box 19 Fairbanks, Alaska 99701 FaJrtnws. Alask.a 99701 Faltbanb, Alash 99701 P,tu C. Jorl,' 'hrlo; S. Udivitz Steven C. Amatrup USGS Alaska Science Center USGS Alaska SCiellU Cenler USGS Alaska ScleI'lC1l Cenler 1011 E. Tudor Road 1011 E. TudorRMd 1011 E. TudofRoad Anchorage, Alaska 99503 Anchorage, Alaska 99503 Anchoolge, Alaska 99503 Oavld R. Kr.ln' NorMn E. W.tlh' AI.n W. Brackney USGS A1as~a Cooperative Fish and USGS Alaska Science Center USFW$ Arctic NalioMI Widlife Refuge Widl~e Research Unit 1011 E. TudOf Road 101 12" Avenoo. Room 236 2091rvlng Bulding Anchorage. Alaska 99503 FIl!lba~S, Alaska 99701 UrWelOiIy 0' AJaska-Fallbanb Fairbanks, Alaska 99775 Grtg J. W,II,r' Rlymond D. C.meron' USFWS Arclic Nallonal \'{Qdlil'o R~fuge Alaska Oepartmem of Fish and Game Thom.l. R. NeC.b,' 10112'" Avenllll, Room 236 1300 Colleg~ Road USGS Alaska SCience Cenler Fairbanks. Alaska (/9701 Fairbanh. Alaska (/9701 1011 E. TudOfRoad Anchorag~, Alaska (/9503 Robtl1 G. Whitt David C. Douglu lflSt~ule 01 Arctic Biology USGS Alaska SClonce Cenler D.n J. Rttd University or A1aska-Fairbanks P.O. Box 240009 Alaska Oepartment of Fish and Game 902 Koyukuk Ome Oooglas, Alaska 99824 1300 CoIIeg~ Road Irving I Buading, Room 311 Fairbanks, Alaska (/9701 Fa~, Alaslr.a 99701 H.ney A. F,llx USFWS Arctic Naliooal WI(lllfe Reruge H.rry V. R,ynord. K,nn,th R. Whltt.n" 10112" Avenllll Room 238 A1aslr.a Oepartment of Fish and Game Alaska Department of Fl:sh end Game Fa~nks, Alaska 99701 1300 College Road \300 CoIIi!ge Road Fairbanks, Alaska 99701 Fairbanks, Alaska 99701 G,r.ld W. G.m,r' USGS Alaska Science Cenler P.trlcl. E. R.ynold. K,nn,th J. Wll.on' 1011 E. Tud(l(Road USFWS Arctic National IIndlire Refuge USGS Alaska Cooperative moorage, Alaska 99503 101·12" Avenue. Room 236 Fish arid Wldlife Research Un~ Fairbanks, Alaska !19701 University of Alaska-Falrbanb Bl1Id Grlfflth P.O. Bo.1: 757020 USGS Alaska Cooperative Donna G. Robertlon' Fairbanks, Alaska !19775 Fish and \'{idlife Research Unit USGS Alaska SCience Center 209 Irving I Bukllng, P.O. BOJl mow 1011 E. Tudor Road Don.ld D. Young" University or A1aska.fairbanb Anchorage, Alaska (/9503 USGS Alaska SCience Center Fairbanks. Alaska 99775 1011 E. TudOfRoad Dould E. Runelt Anchorage, Alaska 99503 JerryW. Hupp NoMem ConsllfVelion USGS Alaska Science Cemer Canadian W~dlife Service 1011 E. Tudor"Road 91782 Alaska Hi;lhway Anchorilge. Alaska 99503 WMehorse, Yukon Tenilorles Y1AS87 Canada • Current addresses: Robert Ambrose, National Park service, WASO, NRPC, Foil Collins, CO Raymond D. Cameron. lnstnule or Arctic Biology. University or A1aska.fairtlanks, 902 Koyukuk Drive. Irving I Buiding. Room 311, Falfbanks. AK 99701 Gerald W. Gamer, doceased PeterC. JOM, U,S, GooIogicai Survey. Upper Mid'Ir\1st Environmental Science Center, 2630 Fama Reed Road, La Crosse. W! 54603 David R. Klein, Inst~ule 01 Arctic Biology, Unlversit)' of A1aska·Fairbanks, 902 Koyukuk Drive, INio:!lBuilding, Room 311, Fairbanks. AI( 99701 Thomas R. McCabe. U.S. Fish and Wildlife Service, EcoIog1cai Sef'lices, Chesapeake Bay Field Office. 177 AdmIral Cochran Or.. Annapolis. MO 21401 Donna G. Rooollsoo, Halllirlg.lawson and Assoclales, 601 E. 57" Place, Anchorage. AI( 99518 Noreen E. Walsh. U.S. Fish and WUdlifll Service, Ecological Services, Atlanta Field Office, 1875 Century Boulevalll. Room 200. Atlanla, GA 30.345 Greg J. Weiler, U.S. Fish and Wildlife Service, Potomac National Wildlife ReltJge. 14344 JeNel!>on Davis H9hway, Woodhridge, VA 22181 Kenneth R. Whitten. P.O. Box 81743. Faifbanks. AI( 99708 Kennelh J. Wilsoo, A1yeska Pipeline Service Company, P.O. Box ro469. Faifban~s, AK !19701 Donald D, Young. Alaska Department or Fish and Game, 1300 College Road, Fairbanks, AI( 99701 x ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL \VILDLIFE RESEARCH SUMMARIES Section 1: Introduction reserves of 1.5 million acres (titled the 1002 Are:l) on the coastal plain of the Arctic Refuge. Background In April 1982, the Arctic Refuge staff completed a report summarizing the then current st:l1e of knowledge The Arctic National Wildlife Refuge in northeastern on the fish, wildlife, and their habitats present 011 the Alaska is one of 16 refuges in Alaska and 539 refuges coastal plain of the Arctic Refuge (U.S. Fish and Wildlife nationwide within the National Wildlife Refuge System Sen'ice 1982). From 1982 to 1985, field investigations of ildministcred by the U.S. Fish and Wildlife Service. First biological resources of the 1002 Area were carried out by established as the Arctic National Wildlife Range in 1%0 a number of investigators, and annual reports summarized by Public Land Order 2214, it initially had a three-fold the results (Garner and Reynolds 1983. 1984. 1985, 1986. purpose 10 preserve unique wildlife. wilderness, and 1987). These reports and other resources were used to recreation values on 8.9 Illillion acres. prepare a DepartlllelH of the Interior report to Congress: In 1980, the Arctic National Wildlife Range was Arc/ic Na/ional Wildlife Rtfllge, Alaska, Coastal Plain expanded to the southwest and renamed the Arctic Rt'SOIlrce ASSt'SSIllt'1l1 - RI!J1orf (///(1 RecOIlllllclUiarioll to National Wildlife Refuge (also called the Arctic Refuge in Ihl' COIlgr,'ss ofthe Unired Slall'S and Finlll this report) when the U.s. Congress passed the Alaska EIII'irolllllt'lIIal I/Ilpact Srart'/II<'1l/ {Clough el al. 1987). National Interest L~H1ds Conser\'ation Act (ANILCA), Biological investigations continued from 1988 through Public Law 96-487 (94 Stal. 2371). This legislation also 1994 in and near the 1002 Area coordinated by research designated almost ,Ill of the original Arctic Nmional scielllists from the U.s. Fish :md Wildlife SCr\'ice who arc Wildlife Range as wilderness, and it directed the now part of the U.S. Geologic:ll Survey (~kCahe et a!. Secret:lry of the Interior 10 conduct studies evaluating 1992). Coll:lboralOrs included speci:llists from the Arctic both the biological resources and the potential petroleum National Wildlife Refuge: Alaska Department ofFish and Game: Univc~ity of Alaska-Fairbanks: Canadi:ln Wildlife - Amkl'<"\.\'I{boo<>d¥y mil.. Arctic National Wildlife Refuge { o 20 4ll 60 !lO 1002 bound.ry ~ and Surrounding Areas 031(,.4961:18 -, In""""'>tionol~ 'fi'" lilomo<= Figure 1.1. Geographic map of lhe Arctic National Wildlife Refuge. Alaska, USA, and surrounding areas. 2 BIOLOGICAL SCIENCE REPORT USGSfDRD 2002·0001 Service; Yukon Department of Renewable Resources; and substrate called permafrost lies below the surface of the the Northwest Territories Department of Resourccs, soil. Winter conditions with below freezing temperatures Wildlife, ;jlld Economic Dcvelopmenl. Additional and snow exist for 8 to 9 months each year, Easterly infonnation continued to be collected from 1995 until the willds predominate most of the year, although storms present (200 I) as part of monitoring caribou (Rallgi[u usually arrive on westerly winds, At K km: ~'Wll bou,w,y 1002 Area ~Nl"""'nd>ty Arctic National Wildlife Refuge J =-I'<>"rn Figure 1.2, Geographic map of [he 1002 Area of lhe coastal plain of lhe Arctic National Wildlife Refuge, Alaska. ___. and __, edit{)f~. 19\\4. Arctic N;ltionJI Wildlife ~kC:lbe, 1'. R.. B. Griffith. N. E. Walsh, D. D. Young, editors, Refuge eO;lSl;11 p]:lil1 resource as~e~slllent: 1983 update I <)<)2. Re~e;lrch on the p(llenli~1 effects of pctwlc\11l1 repon. ba~cline sllJdy of the fi~h. wildlik. :lnd their ha]Jil;1lS. deveioplllent on wildlirc and Iheir habital. Arclic National U,S. Fi~h and Wildlife Servi.:e. :\nc!1orage, Alask:!, USA. Wildlifc Refu~e inlerim repon. I9SS-1990. AI;I~b fish and Wildlife Research Center :l1ld ArClic 1\';llional Wildlife ~,_. ;lIld ..__' edillm. 19155. ,\rclic N;ltional \\'ilJlife Refuge', fairb;mks, AI;lska. USA. Refuge coasl;11 plain resour.:e ;ls~eSsrnenl: 1984 upd;He reporl, h:lscline ~lUdy of the !i~h, wi!Jlik, :llld llicir hallita!. US fish :md Wildlife Servicc. 1%2. Arctic National Wildlife U.S. fish and Wildlife Sen·ice. AndlOrage, Ala~b, USA. Refuge C()~st;r1 plain resource ;Issessrncrll: initial rcpon b:lseline stud)' of the !ish, wildlife, and their ll:lbil:l1s. U,S. ~__, and ~_. editors. 1986. Arclic NaliOlnl Wildlife Pi,h ;lnd Wildlife Service. Rcgion7. Anchorage, Abska. Rcruge cnasta] plain resoUTCc a~SC~Sll1ent: !inal repon. USA. ha,e1ine slUdy of the !ish, wildlife, and lheir hahitats. U.S. J:ish and Wildlife Service. ,\nchorJge, Alaska, USA. ]<)8S. Arclic 1\'alion:l1 Wildlife lkfuge final cOlllprehensive erJllsen'ation plan, envirunmcnt:tl imp;lcl ~ __, and __. editors. 19R7. Aretic National Wildlife statemel11. wildeme.<.' revicw. and wild river plan~, U.S. Fish Refuge cnast:!l plain resource a~seS>tllCl1t: 1985 lJpdmc and Wildlife Service, Anchorage, Alaska, USA. rCjl<)ll, haseline ,tudy of the !ish, wildlife. and lheir halJilat~. {j .S. rish :UllJ WHdhfc Sen'icc, ,\nchorage, Alaska, US,\. ·1 BIOLOGICAL SCIENCE REPORT USGSfBRD 10m-ODOI Section 2: Land Cover We eValuated 3 methods for producing a lilnd-cover lllap from Landsat-TM data: I) a supervised classification Janel C. Jorgensoll, PC/a C. Joria, alltl David C. approach where spectral categories \",ere defined by Doug/as referencc to field d,1t'1; 2) nn unsupervised nppro:lch where spectral Ciltegories were defined by a stlltistical Vegetation Mapping of the Arctic Refuge Coastal clustering algorithm without reference to field data; and PlaIn 3) a modeling approach where the unsupervised classification was combined with ancillary dilla abollt the Documenting the distribmion of Iand·cover types on landscape, such as terrain types, slope, and elevation the Arctic National Wildlife Refuge coastal pl:lin is the (Jona and Jorgenson 1996). Accuracy asse~'Sl1lents fOllndation for impact asseSsmenl and mitigation of indicated that modeling was the best approach due to potelllial oil explor:llion and development. Vegetation limited spectral differences among several tundra maps facilitate wildlife studies by allowing biologists to vegctation types. quantify the availability of important wildlife habitats, Spatial data used to produce the land-cover map investigatc the relationships between animallociltions and included 2 Landsat-TI\-I multispectral images, digital the distribution or juxtaposition of habitat types, and elevation data (including derived slope and sun assess or cxtrapolate habitat characteristics across illumination themcs), and maps of riparian zones and regional areas. terrain types (including hilly coastal plains, foothills, To meet the needs of refuge managcrs and biologists, mountains, thaw-lake plilins, and floodplains), Each of Sil!dlite imagery was chosen as the most cost-effective thesc data sources comprised athelilatic layer in a method for mapping the large, remote landscape of the geographic information system (GIS). 1002 Area. Field dala were collected ,Il 102 sites in lhe Arctic Objectives of our study were the following: I) Refuge, with 5 to 20 plots established in diffcrent hmd. evaluate a vegetation classification scheme for use in cover types at each site over 4 years. The sampling mapping; 2) detenninc optimal methods for producing a lOCations were digitized and a GIS thcme of field-verified satellite-oosed vegetation map that adcqu:llcly mct the land-cover types was produced. needs of the wildlife research and management Field data were cross-referenced with the statistically objectives; 3) produce a digit,\1 vegetation map for the generated spectral classes to determine the most common Arctic Refuge coastal plain using Landsat-lllelllatic land-cover type associated with each of the spectral !'.Iapper (TM) satellite imagcf}', existing geobotanical classes. Because many spectral classes represented mOre classifications, ground data, and aerial photographs; and than one Iand-covcr type, the ancilillry, non-spectral data 4) pt:rform an accuracy :l.~SeSSlllellt of the map. layers were Ilsed to improve the classification (Hutchison The land-c()\'er classification _~cheille developed for 1982), Each spcctral class was cross-tabulated with the the mapping pmject was based on Walkcr's hierarchical field land-cover, terrain type, elevation, sun-illumin>ltlon, vegetalion classification system for northern Alaska and slope layers. 111ese tables were used to guide thc (Walker 1983). During the developmellt of the map, the modeling of decision rules fOr splilling confoundcd scheme was altered slightly to provide a group of land spectral e1asses into separatc land,cover types. Cover classes lhat wcre more cornp,lIible wilh the The land-cover class assigned to each unit area Oil the ill fOrmation contelll of the L:llItlS:Il-Tl'\l .~pc-ctral data and map (30-1Il~ pixel) depended on its spectral class and ancillary data. Wildlife biologists were consulted to associated ancillaf}' data, most commonly slope and cnsure that the system included lantl-cover types relevant terrain type. Preliminary land-covcr maps were produced, to wildlife habitat_~tlldie.~, >lnd then the distribution of each land·cover class WilS We conducted a preliminary assessment of mapping viewed in conjullction with color-infrared aerial tundra habitats with Landsat-TI'-I and SPOT satellite photographs showing vegctation to judge the lIlap image dala. W... IIsed:m intcc-riltioll of the 2 d;\ta sourcc.~ accuracy. Additional field data were gathered for problcm for one study area and uSl.'d Landsat-Tl'Il e;~c1usivclv for ~~e:ls, and thc deci.~ioll mles were modified as necessary. another. Results indicated that the expense (at the ti'me of 1he process was repeated through several itcrations the study) of illlcgr.1til1g SPOT tlat,1 would not be COSI before the final map was produced. effeclive for the enlire mapping project. Landsat-TI\I Thc ll1:lpping methods, datll, sUllllllary statistics, and methods, however, could improve existing maps made an accuracy assessment were presented in a map user's previollsly wilh Landsat-1'.ISS data duc to Tr'\l's finer guide (Jorgenson et a\. 1994). The ima~e processing spatial resolution and additional spectral hands, methods were preSellted ill more detail in Joria and Therefore, further sltldics focused on using the Landsat ~o~genson 1996. Sixteen land-cover classcs werc mapped 1'1'1'1 data. lFlg..1.1.). They included: I) wet gralllinoid tundra, 2) wet graJlllnOid tundra with lO-50t;(, moist indusiolls, 3) moist ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SW.n..·1ARIES 5 SIi' ~ B -- Arctic NVVR Bound.uy Land-Cover Types -- 1002 Boundary Coastal Plain,, Arctic NWR -- Kaktovik lnupiat Corp. Boundary • III 15 :lOrnl • IS 24 12m HERBACEOUS CLASSES SHRUB CLASSES OTHER CLASSES WG - ,Vet G'"m;nold Tunc:a Poorly (lrillneO '~i STT _ Moist Shrub--Tussock Tundra ~nd Wate!· m PV - Pa'1li\1;' Vellcta:cd 10%·50'10 tunc,,, ""lh ~e<.llles or Il'asses "r.d lew ~hrut>!i track Shrub Tundra Tussock lund'a dom,Mted by ~cll"m1Cd 0' mosses erec! ",;1"", and orch. C' 5hrubby Ofa;nage complexes 10 IOC\h,'is 8-\ - earlen <:10% \{eg"!~ted WG//, -Wet G,aminO'd Tund'" W.th lG",(,·50% mo MS _ !lo;si Sedge-"WJow Tund,a Mc>~t lund'a ;C-l I,T - Drya5·G,am,no,d / ;;cdgc-willow tundr:l With lO·5W;}, wei inclusions. 4) on high-ccnlcrcd polygons. 10j Dryas-graminoid alpinc moist sedge-willow lundra, 5) moist sedge-Dryas tundra. tundra, II) riparian shrub. 12) Dryas rivcr tcrracc. 13) 6) mOist sedgc-tussock IUndra. 7) moist shrub-tussock partially vcgclalcd, 14) barrcn, 15) icc. and J6) Willer. tundra. 8) moist low-shmb tundra. 9) moist shrub tundra 6 BIOLOGICAL SCIENCE REPORT USGSfBRD 2002-0001 The land-cover classes are described in dctail in the lypically used in wildlife studies. For example, when the map user's guide, which includes quantitative vegetation map W,IS combined into 6 or 7 more generalized classes cover data, species lists of typical plant communities for ungul:tte habitat studies, ovcr 70~"o agrcement was occurring in each land-cover class, photographs, :llld obtained. TIle greater initial detail of the I6-class lllap cross-reference to 7 other classification systems used in was prescrvcd, however, because it alJows adaptability to northem Alaska. a wider runge of studies. An accuracy assessment was performed with an Proportional occurrences of the vegetation classes independenl data set of 318 vegctation plots that were not across the entire coastal plain and within various terrain llsed to lHake the map. The plol.~ were systematically types were roughly similar between the mapped classes located across the coastal plain and foothills but not and the independcnt ground-truth data set (Table 2.2), across the mOllntains. Point-by-point overall agreement again with the majority of discrepancy arising bctween betwecn the mapped Imld·cover classes and the tield c1osely-rclated vcgetation cOllllllunitics. assigned classes was 50% (Table 2.1). The finalland-covcr map is available to the public in Although land-cover types in the classification system digital format at hllp:llagdc.usgs.gov. 111e ancillary GIS were distinct, land-cover types in the field occurred data layers (topographic data, digitized field data, across a continuum. Almost all of the vegctation in the accuracy assessmcnt point locations, terrain types, and mapped area was less than 0.5 meters tall and the riparian zones) arc archived at the Arctic National strUctural and floristic differences alllOng related types Wildlifc Refuge headquartcrs in Fairbanks, Alaska. were not great. Subtle transition zones betwccn land Because the land-cover map and its associated cover types arc Ch:lf Table 2.1. Contingency lable used to assess lhe accuracy of the land·cover map of the coastal plain of the Arclic National Wildlife Refuge. A!as~a. Table IXlmpares the map's coastal plain and foolhililand-cover classes (rows. ordered by ecological continuum) with field-assigned classes (columns) from an independent syslemalically·sampled data set of 318 points. Land·cover class codes are defined in Fig. 2.1. Lao. W W M M M T S S S D p Cover G G S S S T T p T T v Agreo" Closs M W D T WG 211111 : r iii 11 5 40 WGM 7 i 19 i 4 i 4 : 6 II 1 I i 1 ; 2 i i 44 43 MSW 4 I 9 I '2 I 8 i II 2' II' i i i35 34 MS I i 4 i 15 4 5! ; I! ! i I ! 28 54 MSD I 5 I 4 i 11 18 14 i 1 : j 2 i i 1 i II I 56 32 TT 1'1612'851i3i' 1'1 II ! 77 SIT 1 1 II 1 1: 5 I 13 i 2 2 II I I 25 "52 SP i1! I : i1! 16 Iii I i8 75 ST il' ilj 2 !! I 450 AT -I---ci--jl--_!i-_-'- +I__if--~,~'-,---.:-'-Lt-::-_-:-+1__:--1_+1__-c2:'-f--.::50~1 RS ! i !: 123 1 ill 633 DT iii: i 116! i I 786 PV ! 2 I i ~ 1 I 1! 1 I 1 I i 6 17 SA I'; I !, i I i81 9 89 I-.:W::A':::_1-c-:-+1-c:_i i !: I 1 II 1 I 4 6 67 TOTAL 13 I 40 (-3c,:-ji-4C2:--:3C'----='c'-+i--18:-r-'c5--5:-t--6-+i--=5---'C.,-+i-c'-I 10 i 5 318 ~"Agree 15 I 47 I 39 i 36 i 49 67 I 72 40 40 17 i 40 I 43 I 100 I 80 80 50 ARcnc REFUGE COASTAL PLAIN TErUU:STRIAL WILDLIFE RESEARCH SUll,'t~IARIES 7 Table 2.2, Percent of each land-C()ver class in the land-cover map of the coastal plain of the Arctic National Wildlife Refuge, Alaska, and the percent partitioned among vanous terra'lf\ types, Land-cover dass codes are defined 'If\ Fig. 2.1. land Entire EnUre Mountain Foothill Hilly Thaw Flood Riparian Cover Map Coastal Coastal lake plain Zoneb Class Plalna Plain Plain !--,w"G,,- -2 _,._....£Hl: ,. ~ __<_1 J~L. 41~L. .,,'_... ~ "~L ~._ WGM 9 13/91 <:1 1101 21 19\ 23 39120l MSW 6 9/10\ <:1 4171 10110\ I 23 17113\ 2 ______..§lj?.QJ ~ ., _.. ___~_(m_ .._ .t~J~?J 6 ______}.J.l.!3L. -' _.. -S.. ---- - 1--- ...1.. -.. " - _ 1--- MSD 10 13/12l 3 17/12\ 20151 8 "", TT 21 122l <1 32 133) 23'29' <1 4 '2' rS"TT'--_-I ~_ .._,~. ..J£{§L .1_ _ ,,~~J!.!L _~ .. _~ __ ~.!JQL ~__.._~11QL . 2_ rS"T__1 -"s-l-__,,3.C,,'1lL + 8 6121 °'" __ ° <110' SP 1 1 14\ <:1 1 lSI 1 101 <:1 f 101 AT 2/1\ M 3/4\ Oml 0 <:1~ rR",S'___1__._-"+ 'C1(~J <:1 1 (Ol , <:1 :01 ! ~1_--",-",I4'L,+----,1"-j8 OT 1 1 2/3\ <:1 <:1 ml <:1 ~O\ I <:1 51101 14 PV 6 I 2/21 14 1111 <:1101 I <:1 2161 8 _~j§L _-._~ rB",A ..__ --'_~._j 32 ~_L(QL_ M • __2 .. __.. ""'" ..?JgL . - -.._------______L{9J ,,---- _____ - [-"'c'-_-t 1 3 <:1 (0) ____~1CC!O:L1----',:'-r----'-{OJ ~ ::: 1: r~"':'---,I---6 r---=~- <1 <, IOJ 2 (1) '6 <, '" <:1 101 I <:1 r <:110\ Sq-kmd 18501 12145 7073 6397 1810 I 271 3523 1038 a Entire map excludmg lho mountain terraIn type. b Riparian zone Is Included within the floodplaIn tanaln typo, c Number in parentheses is tho percent covor for each land-cov!1r typo as estimated by an independent systematic field samplo of 756 points. d Number of squam-kilomaters In each terrain type. References Hutchinson, c:. F. 1982. TechniquC's for comhining LanJs:ll and Walker, D. A. 19S3.:\ hierarchical tundra \'cgetalion ancillary data for digital classification improvement. classification cspecially (ksigned for mapping in northern I'holOgramllletric Engineering :ll1d Remote Sensing Alasb. Pages 1332-1337 ill PeOllafrtlst: Fourth ,1R{l):123-130. International Cnllferl~nce. Proceedings, 17-22 July 19S3, Jurgenson, J. c., P. E. Jori:l, T. R. McC:lbe, n. R. Reitz, M. K. University of AI:lska, F:lirb,lnb, NallOllill Academy Press, RaynolJs, 1\1. Emcrs.l\1. t\. \\'illl1~. 1994. Users guide for Washington DC, USA. the land-cover map of the coastal plain of the Arelie Nat'lnnal Wildlife Refugl~. U.S, I'ish and Wildlife Sl'rvice, Fairbanks, Ala"b, USA. Jorin, P. E., and J. C. Jorgenson. 19%. Comparison of threc methotls for mapping tundra with LANDSA"I"·TM digital data. PholOgr:lmmcnic Engineering and Remote Sensing 62(2):163-169. 8 BIOLOGICAL SCIENCE REPORT USGS/BRD 2002-0001 Section 3: The Porcupine Caribou Herd collared animals. Calving distributions were estimated I, fwm 767 calving sites of adult (~3 year old) radio Ii'I IJrm} Gnffilh, D(wid C. Douglas, Noreen E WaLxh. collared female caribou oblained during 1983-2001 !i Donald D. YOIlIlg, Thomas R. McCabe, Donald E. [average of 40 sites per year; fixed-kernel analyses using Russell, Robert G. White, Raymolld D. Cameron, {1m! Least Squares Cross Validation (Silverman 1986. Seaman Kenneth R. Whillcn et a!' 1996. 1998, 1999)1. Concellfrared ca/l'irlg areas were defined as the annual kemel contour thaI included Documentation of lhe natural range of variation in calving sites wilh greater lhan aVerage density (Seaman el ecological, life history. and physiologic.:11 characteristics ;ll. 1998). Annua/ calving grounds were defined as lhe of caribou (Ranglfer /armuhlS) of the Porcupine caribou 99% kernel utilization distributions Obtailled from annUal herd is a necessary base for detecting or predicting an)' calving sites. ExfeTll ofcah'ing was defined as the potential effects of industrial developmellt on lhe aggregale e;"lent of all annual calving grounds. performance (e.g., distribution, demography, weight-gain Vegetation types were mapped from Landsat-Thematic of individuals) of Ihe herd. To Jcmollslr:llc an effect of l\lapper satellile imagery (Fig. 2.1; Jorgensen el al. 1994) development, post-development pCrfOnll<1nCC Illust differ and reduced from 17 to 7 clnsses for caribou habitat from pre-deVelopment pCrfOfm:lllCC whik accounting for analyses (Fig. 3.1). We estimated the Nonmllized any natural envirolllllcntaltrends. lJijji.'rellce \'egl'fatio!l Index (NDV!) (Tucker 1979, We had 2 working hypotheses for our investigations: TUcker et al. 19S6) and snowcover from Advanced Very I) performance of lhe Porcupinc caribou herd was High Resolution Radiometer (AVHRR) data from associated wilh enYlronmental pallems and habitat Nalional Oceanic and Allllospheric Adminislration quality, and 2) acces.~ 10 important habitats was a key (NOAA) polar orbiting satellites. Snowcover was influence on demography. eSlimated using a linear regression Ihat we derived by We s()ught to document the range of natural variation correlaling AVHRR infrared reflectance wilh estimates of in habitat conditions, herd size, demography (defined ~'nowcover extracted from 'lerial photographs collt..'Cted in here as sllrvival and reproduction). sources [lild magnitude lhe 1002 Area during lhe snowmelt periods of 1987 and of mortality, ~listribution, habital usc, and weight gain and 1988 (r =0.87, Tl =80). Cloud contaminaled areas in the loss; and to develop an understanding of the interactions AVHRR illlJges were identified (Baglio alld Holroyd among these characterislics of lhe herd. 1989) ;llld excluded from anal)\~es, as were large water III addition, we invesligated ways that we could me this bodies. AVHRR and 1l1ematic l'.Iapper illlnges were background information, combined Wilh auxiliary trnnsfonned 10 an Albers Equal Area projcction and re information from the adjacent Central Arctic caribou herd, s;lmpled to I-km~ pixel sizc. \{} predict lhe din..'Clion iUld lllilgnitudc ofany potenti;11 effects NDVl indexes the disproportionale refleclance of ncar· of industrial oil development in the 1002 Area of the Arclic infrared radhuion from green vcgetation (Tucker ilnd National Wildlife Refuge on Porcupine caribou herd calf Sellars 1986) in the callopy of plant cOllllllunilies. Thus, sun'ival on lhe herd's calving grounds during June. relationShips between NDVI and tolal green plant hiomass or leaf area index (LAI) would be expected 10 be Data, Methods and Assumptions strongest for planl communities wilh reduced vertical dislributi{)IJ of green biomass ilnd leaf area (e.g., This work focused on the calving and post-calving cOlml1llnities dominated by sedges, grasses, or short seasons of the Porcupilll:: caribou herd. 111e call'ilJg shmbs that arc coml!1on in the Arctic). Due 10 lhe size of season WilS defincd a.~ the 3-week period thaI bcgan wilh the pixels (-I klll)) AVHRR data arc linked /l1ore to the birth ofcalves (spring). Post-ell/ring was defined as landscape processes than 10 individual plant communities the 3-week periodlhat followed the calving Scason (carly (Malingreall and Belward 1992). sUllllllcr). Relalively good corre];lliollS have becn oblained Porcupine caribou herd size wa.~ eSlimatcd by lhe bel ween above ground net primary productivity (ANPP) Alaska Departmellt of Fish and Game (ADF&G) from and se;lsonaJly illlcgrated NDVI (r = 0.89: Pamelo et al. aeriOlI pholO-censusl~s during post-calving aggregalions. 1997), LAI and NDVI when inlegralctl across Only censuses considered reliable by ADF&G were used. physiognomic categories (r = 0.97; Shippen et al. 1995), Variance in annual censuses due 10 llluitiple observers and p!wtosynlhctic biomass and NDVI in small plots (,2 = counting portions or the photo scts was relatively small 0.51; Hope d a1. 1993). Because NDVI indexl'd IOtal whL'n COl1lp;lrcu wilh cadi census (+2%) and was iCllored green biomass and carilll)u arc selective feeders (White illlhe display I)f annual cell.'ill.'iCS l(;-the ncarest I,O{)O 1983), wc assumed lhal lhe biomass of forages eaten by animals. caribou was positively correlated Wilh tOla] green biollla~'s Demngraphy and calf weight-gain were estimaled at tIte lall,bcape scale. rrum repeated locations andlor recaplures of radio- AI{(.jIC REFUGE COAS'rAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SU/'vl!\IARIES 9 OWet Sedge 111 Herbaceous mm Shrub CJ Alpine o Non-Vegetated [J Moist Sedge Tussock Tundra Tussock Tundra II Riparian Figure 3.1. Land·cover dasses onlhe coastal plain of the Arctic Nalional \Vildl"lfe Refuge, Alaska, and eastward inlo the Yukon Territory, Canada, as generalized for studies of the Porcupine caribou herd. Classes are based on Jorgensen et aI, (1994) as depicted in Fig. 2.1 and are expanded to include Canada usin9 a Canadian Wildlife Service landsat-derived vegetation map of the Northern Yukon. Classes on lhis map and their corresponding classes in Jorgensen et a1. (1994) include: Wet Graminoid (WG, WGM, some PV), Moist Sedge (MSW, MS, MSD), Herbaceous Tussock Tundra (n, SP). Shrub Tussock Tundra (SD), Alpine (ST, AT, some PV), Riparian (RS, DT, some PV), and Non·vegetaled (SA, tC, WA, SH). \Ve directly estinlated NDVI at 3 times: NDVI_621 was the most robust NOVl estimate bec;\uSe it I) Nf)\'Ccall"ing - composite (Holben 1986) images was intcrpolated to a fixed date from 2 snow-free im:lges. olll'lined a~ dose a'> pos~ihlc to median calving dale We assumed that NDVl_calving and NDVI~621 ~ach year (mean image date of 2 June. 5E = 2.0 days). represented relative green foragc quantity while Snowcover W:1S also estimated from these images. NDVI_rate reflected forage quality because it estimated Ncgati\'e NDVI \':llues (areas with snOWc()Ver) were the daily accumulation of new plant tissue which is highly convened to 7,ero NDVI. digestible (Cameron ,lI1d Wl1illcn 1980). The quality 2) NDW~lllid'}IIIIt, - approximately 2 weeks arter implication of NDVI_rate was based on the assumption c,llving (mean image date of 16 Junc, 5E = 2.6 ,bys). that caribou for:lge selectively for the most digestible 3) NDVljarly·}uly - during the lIrst week of July food items (While 1983). Because energy and protein (Hle;lI1 imag,e dalll of 3 July, 5E = 2.4 days). intake from milk by caribou cal\'cs remains high during the first 3 weeb of life and then declines as calves From these images \\"e derived 2 additional estimates: increase their intake of vegetation (Whitc and Luid 1984. I) NDVel'llli' - the pixd-based daily rate of increase Parker et al. 1990), we assullled that NDVI~621 estimated ill NJ)VI from calving to mid-June. forage availability to lactating females during the 3·weck Z) NDWJ)21 - NDVI on the fixed date of21 June period of peak lactation derl1;lI1d imlllediately after each year (approximately 3 weeks aftcr calving, c.llvillg. iinearly interpolated from mid-Junc and e:lrly-July Predator distributions and rdativc densities were images). estimated from annual relocations of radio-collared grizzly bears (Unus arclOs), 1983-1994, and from aerial 1:1 years whcn Sllowcover was substantial (i.e., 1986, survey locations of goldcn cagle (Aquila chry.\'(!C{(J.I') nest 19BB. 1989, 1992, 1997) and NDVI3alving was ncar structures and wolf (Callis IUJ1l1s) dens (Fig. 6.1). l,<-'rD, there may have been a small o\'ercstimate of Satellite-collared c:lribou provided supplemental NDV1_rate, In addition. cloud L:over made it impossible inform;llion on distribution throughom the herd's annu:lI hl o[)laill a complete image 011 any fixed date. Thus. r:lllge. Estimates of minimum daily lllOVemel1\ rates were J(J IHULUliJ(..,::\L Sl'IENCE REPORT USGSIBRD 2002 .. (}(}()1 obtained frolll satellitc-eollared animals, 1985- I995, and Caribou food habits were estimated during 1973 from ncar-daily relocations of conventional radio-collared CillOmpson ;lIld 1\kCourt 1(81), 1979.. 1981 (Russell et al. calvcs on the calving ground, 1992-1994. 1993), and for this study during 1993-94 from Data were analyzed with contingency tables, linear microhislOlogical analyses of fecal pellets (Sparks and and stepwise logistic regression, mulli-response Malechek 1968) correcled for forag.e digestib il it y peTl1lUtation procedures (/'vlRPP, Mielkc and Berry 1982), (Duquelle 1984). ,lIld analysis ofv:lriance. Abike's Information Criteria Annual adull caribou survival was estimated in 1983 (AIC: Akaike 1973. Sakamoto et al. 1986) were used for 1992 (Fancy Cl al. 1994. Walsll et al. 1995). Over-winter final model selection. Bonferroni procedures were used 10 calf survival was estimated in 1983-1985 and 1988 provide over:11J experiment error protection as (Fancy et al. 1994. Walsh et al. 1995). }IIII£' cal/sun'ival 'lppropriate. GIS technology, rClllotely-sensed habitat nhe proportion of parturient wdio-collared females daw-Iayers, habiwHJemography relationships, and retaining live c:llves during the last week of June) W:IS simulation modeling were uscd to assess pOlential effects estim:lted in 1983-1992 (Fancy et al. 1994, Walsh et al. ofdisplacement of c;llving grounds on calf survival each 1995) and for this study in 19lJ3-2001. June. Calving disnibutions and vegetation types on the Not all types of data were available throughout the calving grounds were available for all years 1983-2001, elllire primary study period of I(8)-2001. Calf weights hut siltellite-based estimates of NOVI ;llld snowcover near birth were estimated from captured 1- and 2-day·old were only available for the ye;lrs 1985-2001. animals in 1983-1985, and again in 1992-1994. Calf The study area covered the annual range of the weight-gains on the calving ground and cow weights in Porcupine caribou herd (FIg. 3.2), empha.sizing the June and September were estimaled in 1992-1994. calving ground, and was described in the inlroduction to Figure 3.2. For the Porcupine caribou herd: annual range (wide white solid line), calving sites (yellow points), and aggregate extent of calving (thin solid yellow line), 1983-2001. For the Central Arctic caribou herd: aggregale extenl of calving (thin solid white line) and calving sites (white points), 1980-1995. (Adapted from Wolfe 2000). '0"'='- ===,.",..",.. ARCrlC REFU(iE COASTAL PLAIN TE1{RJ:STRIAL WILDLIFE RESEARCll StJ!\IMARIES 11 Illis r~pofl anu in th~ 1987 Final Le,gislativc conslitutes seale·d('pendcllt selection (d. Wiens 1989, EIl\'ironl1lenlal 11l1P;ICl SIOltcllll'lll (Clough el al. 1%7). C)' Neil and King 1998). We pursued this issuc {)f scale depcndency in hahitat selectlOll by the Porcupille caribou Nutritional Importance of the Calving Ground lk'rd at thl' larger sC;lk.s of tlk' allnual calvillg gfOlinds and concentrated calving areas. Spring arriv;ll Oil thc l..'alving ground is lfll' lime of Because the inability to meet laCl;ltion demands may minimum bouy reservcs for llilrf/lri('/j(fell/illt'.\' (Ihosc lower the pcrfomwl/({, (i.e., wcighl-gain. survi\':ll) of ;lhoutto givc birth or accompanicd by vcry young ealn:s) calves, calving ground habitats lllay be iJllPOfI:Ult. They (Chan-MeI,eoul't al. 1999). Thereaftcr, their enagy and Illay be important becau.'e they ean eOlltribllle protein requirements rcach thc highest level of the year substantially to the female and calf protein bud3cts during during peak lactation in the first J wcds of June (White the calving seaSOll, when maternal pmtcin reserves can be and Luick 1984, P;lrker ct al. 1(90). The felllales' low (Gerhart el al. 1996, Chan,l\kLeod et a!. 1999). appetites are high and forage intake rates can match bCt;ltiol1 de,mand only when.' primary production is high Habitat Trends During the Study Period (White l,'t al. 1975, 1981). Small changcs in nlllritional comel]( and digestibility of forage, howevcr, can havc The climate of thc ,·'retie has heen warming in both substalllial Illultiplier effects on digestible encrgy and ~UlJlIller and winter during recent ckcades {Chapman and protein illlake (White 1(83), :lJld thus Ill;]y inlluencc Wal.~h 1993. Groislllan ~t al. 1904, J-loll£hwn et al. 1(95). llutritional perforl1l:ll1ce of Pllrcupine caribou hcrd Temperature increases have been gre;ltcsl ill winter. Tile females on th~ calving grOlHh.!. warming lws been hetCf{lgeneous al,TOSS the Arctic Rccent advances ill idell1ifying the basis of selection (Cllapnmn and Wahh 1993, Serrae 20(0), but was of fool! by ungul:nes (k'mollstrate th • ,-~-'_.------c------. , PoY.r,'" Pha> ~ ,. I l ,< • '\ I il .!::j o· ro -g"·1 . If)" .21 V POO phJ50 shilb' L~~"3::~.~~.:-~:,:~-_~j" ._,_~_-.~.~i ~ .J __ __ ,. y.__• __ I&~5 1(165 \97~ 1%5 1995 2005 j Year i' i,i Figure 3.5. Standardized values of the Arctic Oscillation (AO) for Ii Ii winter (January, February, March) and population size of the Porcupine , caribou herd, 1958-2001. Mean value indicated by solid horizontal line. Ii 'IS ~i • PDO the Pacific Decadal Oscillation (Hare and Matuna, 2000). Ii ii and a coolnegalivc phase when surface pressures are relatively high. Initiation of increasing and decreasing trends in the Arctic Oscillation has been coincidelll with phase shifts in the Pacific Decadal Oscillation in 1977 :md 1989 (Hare and l'.fatuna, 2000) (Fig. 3.5). Correlations between the closely rehllcd North Atlantic Oscillation and a number of vegetative and ungulate population characteristics have been reported for Northern Europe (Post et al. 1997, Post Figure 3.3. Mean temperatures for 2 stations within the Porcupine caribou herd's aggregate extent of calving (Komakuk Beach and and Stenseth 1999). Shingle Poinl, Yukon Terrilory, Canada) and 1 stalion \\ilhin its winler Median annual NOVI at calving (NOVCcalving) range (Old Crow, Yukon Territory) for al June, and b) winter (January, within the extent of calving of the Porcupine caribou herd February, March), 1950-1995. was positively correlated with the Arctic Oscillation from the winter (january, February, l\-'larch) of the previous t"aJclldar year (-15 month lag, r = 0.32, P = 0.011) (Fig. 3.6). 'nlis suggested that early forage availability for m lactating females was influenced by weather patterns on a ~ hemispheric scale. ro 1, U o~o '\ Further, the suspected phase .~hift in the Arctic I, ...... •------_•... Oscillation at the end of the 19HOs (Fig. 3.5) was c ----~--' ,.' coincident with an increase in the frequency of daily ~ 0:;0 'j' .' ~ • tellljJerature excursions above freezing in both the spring • (Fig. 3.711) and fall (Fig. 3.7h) on the transitional ranges N , of the Porcupine caribou herd during the 1990s. There hns .5> o?O-1, o bccn a decre-:lse in the depth and extent of snowcover in z Northwestern Canada ncar the willlering ground.~ of the Porcupine caribou herd during this latter period as well o10 -;~!:,; 0'-;-r07 '-i-~~;_~i;~1 ',';;:;"3 T ',,,ch"--;'l:.{"';r&3 - fOOl (Brown and Braaten 1998). Year 'I1ms, forage biomass during peak lactation demand lNOVI~621) increased during the period of study, 1985 Figure 3.4. Median Normalized Difference Vegetation Index (NOVI) on 1999 (Fig. 3.4), and this positive trend was coincident 21 June wilhin the aggregate extent of calving for the Porcupine with snlllmer warming on the calving ground (Fig. 3.3a). caribou herd, 1983-2001. Values for 2000 and 2001 were outliers In addition, forage availability at calving (NDVI_calving) (RStudent =-2A9, -2.86, respectively) and excluded from the has been positively cl}ffe]aled Wilh hemispheric-scale displayed regression line, r,= OA96, P=0.002. ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SU1\l!\IARIES 13 ,j ;:; D:'~ ~ O:ill co o o o 00 go,';' . I. 16 ~ U <'" GO;:>;) . o ~on " c f , ~ 8 ~I 0 TO ~ 6 Of.~ ,)C'. 1 ., Z 0 000 .': "'. ~ ·1', ·'0 ·DO 00 O~ 10 T5 ~O ;,~ 30 0• AO Index (JFM) - Previous Year , tncrease 1970-1989 DeCline - 1990-1999 Population Trend Figure 3.6. Mediarl Normalized Difference Vegetalion Irldex at calving (NDVI_calving) wilhin the aggregale extent of calving (Ee) of the bj Porcupine caribou herd for the currenl year, and winter Arctic Oscillation index (AO, January. February, March) for the previous co o -j- calendar rear, 1985-2001, !\ 16 ~ o atlllospl1l'ric L'onditiolls (fig. 3.6). Courlterilctlng tht. "'§ ,.; I- positive trend in forage abundance during peak bct:llioll ~ has htcn a tendcncy IOwaI'd Illore fr~~ze-tha\\' cyclcs on • tr:lJ1~ilional ral1g~~ ,- spring and fall of thc Porcupinc ~ I .~ c Porcupine c3ribou herd size appeared correlated with There werc no significant differcnces inmcan Arctic Oscillation nlthough there were too few data 10 panurition, calf survival during Junc, or nel nllf conduct a proper time series ilnalysis (Fig. 3.5). In production (defined as the produc{ (l( panurition rate and contrast to the Porcupine caribou herd, DIller Alaska June calf survival) (Fig. 3. lOa-c) bctwcenthc increase. barren-ground caribou herds (Westem Arctic, Tcshckpuk and decreasc phases of the herd (Fig. 3.8). Panurition rate Lafrc, Central Arctic), generally continued 10 increase aver.lged 0.81 (range 0.71·0.92) during 1983·2001 (Fig. during the downward trend ill the Arctic Oscillatiolllhat was evident during lhe 1990" (Fig. 3.5), ,j Capacilyfor growth (defined as tlIe Illaximum realized 10 T lung-Icnn growth rate) of the Porcupine cariboll herd appeared subslalllially less than for oIlIer Alaska herds. ,,1 ] fl nj Capacity for gn)wth ,\lllong herds of dranwtically different sizes is best visualized by plolting rc!atj\'c herd si;tes (Fig. 3.9). r.'!aximulll long-term growth rate (-4.9 t.'O, t:: II] I) r 11j,i1 h1 assumed linear, 1979-1989) (Fig. 3.8) of the Porcupine caribou hcrd was nevcr morc than about half tlle rate observed for other Alaska barrcn-grollnd caribou herds i:: mIIIIIIIAII!IIIUIII'11 W [Westcrn Arctic herd (1976-1996. -9.5%), Teshekpuk Lake herd (1978-1993, -13%), Central Arctic herd (1978 1992, -10.3%)1 (Fig. 3.9). 1saJ 1$55 smi ir.gi 1993 1995 iwi' ;~ l ~; The Porcupine caribou herd was the first AI:lska Year barren-ground c:lribou herd co begin and maintain a prolonged decline in the last 2 dec:ldes (Fig. 3.9). Annual bj ,, survival of Porcupine caribou herd adult females was only about 34% (Fancy et al. 1994, Walsh et al. 1995), which W:IS lower than lhat generally observed in other c:\ribou herds (BergenJd 19S0);and adult female survival may have been respollsible for the relatively low growth rate of the Porcupine caribou herd. Annual calf survival averaged ahOllt 48'7;' with about half (56'70 of the annual 1lI0nalil)' occurring on the calving ground (Whitten et:ll. 1992, Fancy et al. 1994, Walsh et al. JlJ95). oj ~ 10-f PCH -178K ~ rn 091-, .- c , WAH - 463K .-.- "1?: 0 B -j- j-. '11 (' CAH·27K ro I" 'j'll ~""I ,I f1 II 'I'" --,]j- 1f);1 ')J ;" !J ;. ------_ .• - TLH - 28K "r' j'" 'I --- ...-.__ .. 'c'" i ,j' '1"-1,1" li,,!1 Ii/,' "o ii'"e" ",';"""I I' _",I1'1'11'"n Iii 5"' ,,1'1,- IIIJi, 111'11-; I' I" ''''I'1 I, 'I [1' tro 1i"'I'"",' II '1'1' "'11 ,,;,I,]1' '1' I'i a. O~ ".",.j".~,I·,·· "., Co<: I,. f'.·' ," 1'1.,...• I,' ''-;'i'I,". ".,..I,' "C' ,-. f" '.' .'.,"II'.• __ ....,l.••j ..",L,,,J,L.L_._..,•. l,....,.c.l,...,...,L._.., li'53 I%~ lM7 1,-69 1l.'S1 19$3 I¥.h 19")7 '.'3"-" X>:ll Year FIgure 3.9. Relative post·calving herd sizes (minimum observed = 1.0) of the 4 Alas~a barren·ground caribou herds (PCH =Porcupine Figure 3.10. ReproduClivEl eslimates for [he Porcupine caribou herd, caribou herd; WAH:: Western Arclic herd; CAH :: Cenlral Arctic herd; 1983-2001: a) parturition rale of adull females, b) calf survival from TlH =Teshekpuk lake herd), 1976-2001. Maximum observed birth through Ihe last week of June, and c} net calf production (the populalion size for each herd is noled in [he legend. product or parturition rate and calf survival]. I ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUMl'I·1ARIES 15 3.lOa) and did not differ between the increase plH'lse c31ving ground and was directional toward the annual (0.80, SE =0.04, 1983-1989) and the decrease phase calving ground. (0.82. SE = 0.08.1990-2001). After their calves were born, the direction of Calf survival during June was quite high and aver;lged movement ofsatellite-collared parturient females was 0.75 (range 0.57-0.94) during 1983-2001 (Fig. 3. lOb) but random for 20 days (Fancy and Whinen 1991). Calf did not differ between the. increase phase (0.71, SE = lHovement rate (minimum, stmightline, estimated from (J.07, 1983-1989) and the decrease phase (0.79, SE = conventional radio-collars) in the ye3rs 1992-1994 was 0.13, 1990-2001). Net calf production averaged 0.62 about 2.5 km/day during the first week after birth. The during 1983-2001 (range 0.50-0.82) (Fig. 3.lOc) and did f3te incrcased gradually during the next wcek to nbout 5 110t differ between the increase phase (0.58, SE = 0.06, kill/day and then inere;lsed through the cnd ofJune 10 1983-1989) and the decrease phase (0.63, SE::: 0.13, approxinl3tely 15·20 km/day. As fellwles 3nd calves 1990-2001). For all these demographic characteristics, departed the c31ving ground in late June and early July, variance tended to be greater during the decrease than some individual calves traveled as much as 90 km/day. during the increase phase of the herd. Helativcly high rate of movement continued throughout Because average parturition, calfsurvival during June, July. Because movement rates were low during the and net calf production did not differ between the calving season and directioll of movement was random increase and decrease phases of the Porcupine caribou for 20 days after birth (Fancy and Whitten 1(91), the herd, 1983·2001, a reduction in adult, sub-adult, and/or distribution of c Figure 3.11. Distribution of satellite-collared female caribou of the Porcupine caribou herd during 7 time periods, 1985·1995. An average of 10 animals (range 4-17) were collared each year yielding 14,447 observations; 87% of these Observations were obtained 1985-1990. Not included were the locations 013 females that each spent one winler with the adjacent Cenlral Arctic herd. ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUl\llvtARIES 17 2,548 km2) and contained 471,:;' (range 29-6) %) ofcalving locations. There was no concentrated calving area in 2001 when the spring was very late and the eXlent of calving was almost completely snow covered. Density of pal1urient females in the concentrated calving area ranged approximately 13-106/km' over the years and averaged 7 limes (range 3.7-10.8) higher than outside the concentrated calving area each year (Table 3.1). None of lhese estimates differed between the increase and decrease phases of the herd (P > 0.05). Since 1972, there have been only 2 ye::lfS (2000, 2001) when all calving occurred in Canada and I addition::!1 year (1982) when all Jun Jul Au,) S Figure 3.13, Calving dislributions of the Porcupine caribou herd, 1983-2001, as eslimated from fixed kernel analyses of lhe sites where radio· collared femates were firsl observed with calves during repeated aerial surveys in May and June, There are 3 zones: 1) concentraled calving area (shO'Nn in dark gray), the conlour enclosing calVing sitos with greater lhan average fixed kernel densily, 2) annual CiJlving ground (medium gray), the 99% fixed kernel ulilizalion dislribution for ayear, and 3) aggregate exlent of calving (light gray), the ouler perimeter of all annual calving grounds, No concenlrated calving was detecled in 2001. ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUl\IMARIES 19 1 l Tabla 3.1. Number of calving sites, number of calving sites in the concentrated calving area (CCA), area (km ) of CCA, area (km ) of annual calving ground (ACG), ralio of sizes of CCA to ACG, population size of the Porcupine caribou herd, percent of radio-collared female caribou that calved in the CCA, percent of radio-collared female caribou that calved in the 1002 Area, percent of the CCA within the 1002 Area, and percent of the ACG wilhin the 1002 Area, 1983-2001, Alaska, USA, and Yukon Terrilory, Canada. CalVing Sitos In CCA ACG Ralio Population %females %Iemales %CCA %ACG Year SHes CCA Area Area CCA/ACG Sizo (K) InCCA In 1002 In 1002 In 1002 1983 18 11 2,584 10,064 0.25 135 55.6 61.1 62.4 42.8 1984 18 11 839 6,599 0.13 61.1 33.3 19.8 39.2 1985 34 16 1,585 10,784 0.15 47.1 55.9 69.2 36.8 1986 20 8 419 5,432 0.08 40.0 10.0 28.8 8.4 1987 36 15 479 6,048 0.08 165 44.4 13.9 14.2 15.7 1988 61 24 267 3,823 0.07 39.3 1.6 0.0 5.9 1989 51 15 255 3,872 0.07 178 29.4 33.3 59.3 30.1 1900 53 22 1,167 8,379 0.14 39.6 69.8 100.0 47.2 1991 43 21 731 5,767 0.13 48.8 88.4 92.5 68.6 1992 43 18 2.174 16,667 0.13 157 41.9 41.9 79.1 22.5 1993 35 18 1,401 9,098 0.15 51.4 57.1 70.2 40.3 1994 79 33 814 6,602 0.12 152 41.8 84.6 n.3 54.8 1995 60 31 827 5,141 0.16 51.7 91.7 100.0 71.2 1996 65 30 1,354 9,453 0.14 46.2 53.8 90.6 33.• 1997 29 15 530 5.661 0.09 51.7 31.0 33.7 31.8 1998 39 20 789 6,316 0.12 128 51.3 84.6 93.4 73.1 1999 20 • 601 7,820 0.08 45.0 20.0 9.3 30.4 2000 22 13 791 8,541 0.12 59.1 0.0 0.0 0.0 2001 41 a 10,602 123 0.0 0.0 average 40 18 976 7,604 0.12 148 47.0 42.7 55.5 34.3 minimum 18 8 255 3,872 0.07 123 29.4 0.0 0.0 0.0 maximum 79 33 2,548 16,667 0.25 178 61.1 91.7 100.0 73.1- SE 18 7 630 3,060 0.04 20 7.8 30.1 35.9 22.5 a No concentraled calving was detected in 2001 . 0.00 0,05 0,10 0.15 0.20 025 0,30 0.35 NDVLcalving - Extent of Calving Figure 3.14. Percent of radio·collared Porcupine caribou herd females Figure 3.15. Pelcent of radio·collared Porcupine caribou herd females that calved in the 1002 Area of the Arctic National Wildlife Refuge, thai calved withill the 1002 Area of the Arctic National Wildlife Refuge, Alaska, 1983-2001. Alaska, in relalion to the median Normalized Difference Vegelation Index at catvillg (NDVI_calving) ',~i!hillthe aggregate eXlent of calving, 1985·2001. Point legends indicale tM year of the estimates. 20 BIOLOGICAL SCIENCE REPORT USGSfBRD 2002-0001 and Game, personal communication). As a result of these -) westward movements, essentially lhe entire 1002 Area was eventually used by late June or early July. ~Iost of ~ the usc of the weslernmost portion of the 1002 Area by satellite-collared females of the Porcupine caribou herd occurred during 24 Jllne-14 August (Fig. 3. I I). Foraging on the Calving Ground ~jlUJ~.W,; "'i,L'~i"ll'~ ~ ~ ~" ~ i - JVHEl9"34 JULY The calving season diet of Porcupine herd c;lribou CD o:,ltOl'J{Jf Figure 3.17. Porcupine caribou herd a) diet composition and b) median phenology of major forage items, 1994. Diet composition estimated from microhis!olOjJical analysis of fecal pellets, corrected for digestibility. Phenology scores for cottongrass: 1 =leaves only, 2 = nowers in boot, 3 =early flower, 4 =lull nower; and, for willow: 1 = dormant 2 = bud swelling. 3 = leaf unfolding, 4 =fuli leaf. Thompson and l\kCourt 19H I, Kurop:!1 1984, Russell ct al.1993). Cotlongrass flowers wcre most common in the veget Caribou maintained the willow and herbaceous diet 1987; Fr)'xell 1991, 1995), but analysis of selection at the until they depaned the calving ground near the cnd of founh order for the Porcupine caribou herd was beyond Junc. Because climate warming and earlier gn::cning Illay the scope of this repon. increase the carbon:nilIogcn ratios of individual forage For the purposes of the m;ltcrialthat follows, we species and reduce their quality on fixed dates (Walsh CI define fifth order selection as the comparison of use al. 1997), rapid shifting among forage species lllay allow within the annual calving grounds (ACG) to availability caribou 10 accommodate lime-specific reduction ill in tlle extent ofcalving (EC), written as ACGIEC nutritional quality of individual plant species that (hereafler called cail,jllg grow/(f sdcclion). We define accompanies climate warming. xi-t'th order sekctioll as the comparison of use within Diet of Porcupine herd caribou was substantially anllunl concentrated c:llving arcas (CCA) to habitat different when they used the Canadian portioll of the availability within the annual calving grounds (CCM extent ofcalving than when they used the Arctic Refuge ACG, hercafter called cOIlCt'lJlraled cah,jllg seleclion). coastal plain and the 1002 Area. Rcgardli:ss of timing of Because Ihac was spatial dependency alllong habitats snowmelt in Canada, calving did there was dominated by (vegetation, NOVI estimates, snoweover; all inventoried mosses ;lnd evergreen shrubs (58.4-73.5%, Russell et al. from the same I-km' pixels) we present Ihe results for 1993). These forage groups were much less digcstible each habitat attribute separately. Selection was assesst.'d Ihan the iillmalllfe cottongrass llowers and willows by comparing mean usc/availability ratios among years (Russell et al. 1993) that dominated the calving diet of the with the null use/avail:lbility r Cloud Figure 3.18. Annual condilions of snowcover and vegelatiorl phenology derived from Advanced Very High Resolution Radiomeler (AVHRR) satellite imagery during the calving period (30 May· 5 June), 1985·2001, for the Porcupirle caribou herd. No concentrated calving was detected in 2001. ! ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUto.1MARIES 23 'J + ,-" o fl- £ ~"'" J", j" ", bJ M + Figure 3.20. Average percent of area in 4 exclusive snowcover classes for the aggregate extent of calving, annual calving grounds, " and concentrated calving areas of the Porcupine caribou herd, 1985 M 2001. Statistically significant selection or avoidance (P < 0.05, overall , + 5:.0 experiment) in comparison with the calegory to the left is indicated by , 'to or '." above the bars. For example. female caribou on the annual &10 ; calving ground avoided areas of 0-25% snowcover and selected areas !~ of 26-50% and 51-75% snowcover when compared with availability in , the aggregate extent of calving. No significant selection of any " snowcover class was detected for the concentrated calving area when " compared with availability in the annual calving ground. 0 ----" h1llh- r~DVI_c'M~~ CIlE••• (1.68x, P =: 0.001), avoided alpinc vcgetation (O.34x, P < 0.001), and werc non-responsive (P > 0.18) to the [J&':~~l 01 Cl>r,i"1l ElliJ Mou.1 C'M"~ Grwnd • eo.-.c"nu.:O r~DVl.-e21 Ci ... and sixth (CCMACG) ordcrs. 'llle work of White et • o lcc'-_-c:-L_; l L '-_L__ ~-'- CIlnlrnl Arctic POlcupino Bolhursl Goorgo Rivor Caribou Herd Figure 3,21. Average percent of area in 6 vetetation types for the aggregate extent of calving, annual calying grounds, and concentrated Figure 3.22. Estimated 10tal intake of dielary niltogen (9) from !he calving areas of the Porcupine caribou herd, 1985-2001. Vegetation calving ground (25 May - 14 June) for 4North American caribou herds. types: Wsedge::: wet sedge; Msedge::: moist sedge; HerbTT::: Forage composition of diet and nutritional composilion of forages were herbaceous tussock tundra; ShrubTT::: shrub tussock tundra. Alpine. estimated from locally collected samples. Intake tales were estimated and Riparian. Statistically significant selection or avoidance (P < 0.05, Itom White el al. (1975). overall experiment) in comparison ....'ith the category to the left is indicated by "+. or·o • above the bars. For example. the female caribou ground as did the Porcupine caribou herd (Fig. 3.22). It is on the annual calving ground avoided the Alpine vegetation type and selected the HeroTT vegetation type when compared with ayailability likely that the proportion of the annual nitrogen budget in the aggregate extent of calving. and on the concentrated calYing obtained from a cah'in£ ground is positively correlated area the caribou showed similar selection when compared v.1lh witll the relative value of the calving ground to tIle availability in the annual calving ground. nutrition of a herd wilhin its annual range. lllcrc were no clear difference~ in pallerns of Effects of Insect Harassment on Habitat Use selection of any types of h:lbitat~ between the incre:lse and decrease phases of the herd. 11lis observation is 1\-10s(]uitoes (Cllcu/ida~') and flies of thl': family tempered by tlle fact that habitat selection was assessed Oestridae arc known to harass carihou. although for only the l:lst5 years (1985-1989) of the iJlcrc:l.~e h;uasslIlent by Oestrid flies Illny OCCllr primarily after phase, but has bC!:1l nssessed for nlll2 years oftlle Porcupine herd caribou leave the calving ground. current decline (1990-2001). Lactating females that are disturbed by insects may 111e shifting location of annual calving grounds within experience a negativc energy balance due to increascd the ex lent uf calving was apparently a functionnl respouse movelllent rates when trying 10 escape harassment by to :lllllually variable landscape pallerns in the qualllity of insects (White et :d. 1975. RlISseli et al. 1993). When easily digestible forage (NDVCrate). The location of harassment causes lactating felllnlcs to substantia.lly cOllcentrated calving areas within annual calving grounds reduce foraging time, calf growth lIlay be reduced (Helle was an appnrent function;11 rcsJlonse !O forage biomass and Tarvainen 1984, Fancy and White 1987, Russell et al. (NDVLcalving, NDVI_621). 1993). lllis functional response to h;lbitals allowed During wann and calm days (mean temperature> IJoe Porcupine. caribou herd fcmales to allain suhstantial and mean wind speed <6m/sec) when conditions were illsect~ intakes of nitrogen (Fig. 3.22) based 011 estilll;\ted diet sllch that caribou were likely harassl'd by (Nixon composition (Figs. 3.16(1, 3.170), estimated nitrogen 19(0), Porcupine herd caril)()u prefcm~d dry prostrate content of consumed forages, and consumption rates shrub vegclation types on ridgc tops in the fOOlhills and presemel! by White ct ;11 (1975), White and Truddl 1ll0lHIlains of the Brooks Range, clcv:lled siles on the (19801/./1), and Trudell and While (1981). -lllUS, Ihe coastal plain, and areas adj:lcent 10 the Beaufort Sea Porcupine caribou herd calving ground was clcarly C(Ja.~t, apparently lO gain relicf frolll f]losqui(()es (Wabh el important to the ;\nnllal nitrogL~1l budge! of I;lctaling al. 1992). rcmales and was likely important 10 the annual energy Porcupine Ill'rd caribou did !lot display as strong a budge!. tendency to move to the coasl!ine during plltclltial insect The :ldjacent Central Arctic herd obtained only about hnrassillent as has been seen for tile adj;K:clll Central Observation.~ olle-quarter as llluch dict;lry nilrogen from its calving Arctic herd. of Ill\JVCl1lellts of unmarked nnimals during survey flights, howcver, indicate that , t\Rcnc REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SU~Il\IARIES 25 segments of the herd oflen follow the coastline while moving along the coastal plain of the Arctic Refuge in July (F. J. Mauer. U.S. Fish and Wildlife Service, person::li cOllllllllniculion). ~, Individual radio-collared caribou showed at leasl 11 partial fidelity (Le., caribou repeatedly returned to ~I~ [J specific areas) to either the coastal plain, foothills, or i I' II Q-.3wccks mountain zones during the insect harassment season in , liil !< mn differellt years (Walsh ct al. 1992). 111C negative energetic I~f~ I' 1"'1';11 riWl consequences of insect harassment (I-Idle and Tarv:lincn 'III' IIII' 4-5 weeks 1984) suggest that frce access to insect rdicfhabitat is ", I' I ""'I II'H[1 1,111 imp0l1:1111 to caribou (Walsh ct al. 1992), but in sOllie I,'1 1'11 '\",:: 1',,1,'1 herds the energetic cost of insect harassment may be low , 'Iili J dfill, (Toupin et :II. 19(6). - 11993' ---- 1994 Year Calf Performance In Relation to Habitat Use FIgure 3.23. Daily gain (kg) of caribou calves of the PorCtJpine herd, t.lean calf weights wilhin 1-2 days of binh \liere 1992-1994, durin9 2 periods (O-3 weeks post·birth and 4·5 weeks post· birth). Gain was estimated from sequential weights or recaptured radio remarkably similar among years. On averagc, female collared anImals. Means are listed above the appropriate bars. calves caught during 1992-94 when the herd was declining weighed 6.2 kg, slightly less (I' = 0.003) than ~;;2-day-old female calves caught during 1983-85 (6.7 kg, time that calves spent in any particular ve,getalion Iype or Whitten et al. 1992) when the herd was increasing. in any class of forage at calving (NDVCcalving), rate of i The increase/decrease classification, however, increase in forage during lactation (NDVIJate). fOnlge I explained only about 9% of the variance in calf weights. available at the peak of lactation (NDVC621), or I 111e difference in female calf weights between the ~nOwcover(P > 0.05). increase and decrease phases of the herd was due solely Although individual calf weight-gain was not J :1 to a cohon of heavy calves in 1985 (7.2 kg). Female explained by within-annual-calving-ground habitat usc, calves caught in 1983-84 weighed an avcnlge of 6.3 kg several characteristics of parluricnt females and calves j (Whinen et al. 1992). were rclated to habitat conditiolls in the anllual calving ·1 There was a significant interaction among years and grounds, 1992-1994. 111e rank orders of I) NDVC62I in j between Jleriods (O-3 weeks and 4-5 weeks after birlh) (I' th~ annual calving gwund, 2) average parturient fcmale < 0.001) in daily weight-gain of fcm:de c;llves, 1992-94 weights (Fig. 3.25), 3) p:lr1urient femalc'hody condition (Fig. 3.23). Daily gain wa's panicularly low during tIle scorc, and 4) average calf weights, all at 3-weeks post fourlh and t1flh weeks of life for calves born in 1993 (Fig. calving, were all the sallle (1993 > 1994> 1992). I 3.23). Lack ofcorrelation betwccn indi vidual calf weight Daily weight-gain of CDlves did not differ between gain and usc of annual calving ground habitat suggests calves born in the concentrated calving are~IS and inlhe that the location of annual calving grounds Illay have peripheral calving areas (I' = 0.214). ~Iuch higher relative maximizcd calf weight-gain, given the conditions of the densities of caribou (7x. on average) in Ihe concentr:l!ed annual habitat avuilable within the ex.tent ofcalving. Once calving area~ compared to peripheral calving areas lll;lY the annual calving ground WHS located in an area that have reduced forage available to individuallacta!illg provided a high propUrlion of easily digestible forage females. (high NDVI_fate), then variation in caribou density and Even tllOUgh cOllcelllrated calving areas fwd a greater forage biomass (NDVI_calving, NDVL62I ) may have proponion of area with high plant biomass (both interacted to reduce vari;l\ion in performance among the NDVI_calving ;llld NDVC621) than did the annual individual study animals. calving grounds, the differential ill forage abundance was cvidellily not sufficiellt to overcome the higher densities Factors Associated with Calf Survival on the of caribou in the cOJlcentrated calving :In,'as and to Calving Ground enhancc the weight-gain of calves horn there. Paltcl"lls of habitat use by calve.~ var-icc! signit1c:llltly During 1983-19H5, average 1ll0l1ality \)f calves during if> < 0.(1) betwcen periods :llld ;\IlHlng year.~', 1992-199-1 June was 29';,,;; (Whitten et al. 1992), slightly higher than (Fig. 3.24a·(;), but were generally similar to use of sites the 1983-2001 avcrage of 25';';". III those early years, about for calving (Fig. 3.21). Weight-gain of cal\'cs during 61 % of mortality on the calving ground was due 10 calving ground usc was 11ll! :lssociated with the percell! of predation antlt!ll'. !L'll1ainder 09%) was due to llI11ritional 26 BIOLOGICAL SCIENCE REPORT USGSIDRD 2002-0001 or physical charac{~ristics of calv~s (Whitten et al. 1992, Predation occurred further south and at higher elevations Roffe 1993). 'nle interaction betwe~Jl nutritional status of ncar the foothills during 1983-1985 (Whilten et al. 1992). the calv~s and pr~dation mortality was not known. During 1983-1985, golden eagles caused most predation mortality of calv~s on the annual calving grounds (-60%), grizzly bears mnked second (-24%), 0) and wolves ranked third (-16%) (Whillell et al. 1992). Young and l\1cCabe (1997) estimated that bears killed about 2% of calves during 1994, a year with rclativ~ly high overall calf survival (Fig. 3.1 Ob). Immature golden eagles ranged throughout the coastal " plain and foothills (Clough et al. 1987), while golden ".' I; I"~ cagle nests and wolf dellS were primarily restricted to the i foothills (S£'I' Fig. 6.1). Grizzly bear densities were rjii moderate and their distributions were concentrated in the foothills (Voung and McCabe 1997). In late summer through winter, the source and distribution of predation II R'~,,"~ Hort>n _J1._"L,lls ....ubn ",'p;.,,, mortality ofcalves were unknown, but wolves were Vo>g<)!aiJoo Typ<> probably the dominant predator. DM ,'"030 ]- 1- r: 0 028 " E i "eo 0213 , f ,1 I- -,5 B 0.24 - -is N 9 ... 022 - < ;; 020 • ;:," " ~ ~, 0.18 I " ~ [) 113 ~ n 2 , ; 0\4; 1.._--- 1S92 199J 1994 " I Y~3' Figure 3.24. Availability of 6 vegetatiol1types in the aggregate extent CI r·:DV'_"~1 FCm.l!<"M . ~1 JlJ"" of calving for the Porcupine C Ihe coastal plain with lower suspected density of wolves, eagles and bears; and greater (8.3%, P = 0.026) if born in the 1002 Area. The survival advaillage of high density calving to individual calves tended to be greater when calves were born in tIle foothills and mountains than when lhey were born on the coastal pl:lin (14.3% advantage vs. 7.9% advantage, respectively). Individual calf survival was not related (P = 0.160) to the fre(jueney of use of its binh site as :l ponion of the eonecntrated calving area, 1983-1994, but calf survival was 100~:er (9.9%, P = 0.026) if the binh site was in an O~ O~ OM o~ ,., area n4'er used as a concentrated calving area. In a NOVI_621 . Extent of c~tYing stepwise logistic regressioll analysis thai simultaneously considered calving density, tillle of binh, zone of birth (coastal pl:lin or foothills), and in or out of the 1002 Area, Figure 3.26. Call survival through June for the Porcupine caribou only calving density (P = 0.004), time period of binh herd, 1985-2001, ill relation to median Normalized Difference Vegetation Index on 21 June (NDVC621) .....ithin the aggregate exlent (early, middle, late; P = 0.(12), and zone (1' = 0.(08) of calvillg (EG). Legends identify the year of the estimate. Calf survival entered Ihe lllodellh:ll predicted individual calf survival, was not estimated in 1986 because inclement weather prevented a 1983-1994. complete sample in fate June. Calf survival for 1993 was a significant '111C surviv:lI advalllage of both high calving density ouUier (RStudellt = 3.84, see lext for biological justification) and was and being born near the middle of the calving period may excluded from the estimated regression lill8 {f' =0.85, P < 0.0001). havc been due to predator swamping where high spminl Upper and lo.....er dashed lines indicate 95% confidence intervals on the and temporal densities of calves may make it difficult for predicted observations. predators to capture individual calves (Hamilton 1971). Bears tended to be less successful at capturing calves in modd can be used to assess whether calfsun'ival during the concelllrated calving areas of the Porcupine caribou June is affected by development. herd (Young :lnd McCabe 1997). Calf sun'ival for 1993 was an outlier (RStudent = When assessing the proponioll of the unnual 3.84) and excluded from the estimated relationship population of calves that surVived during June, the liming between NDVI_621 in the extent of calving and calf of binh in relation to other calvcs W:1S not applicable, but sun'ival (Fig. 3.26) alld from all subsequent models of median calving date, J983-1996, was available. In calf sun'ival. During 1992, :ltlllospheric aerosol.~ from the addition, we could consider Ihe relativc alllount of food emption of fl.lt. Pinatubo in the Philippines re'1clled the (NDVCealving, NDVCrate, and NDVL621), winter Arctic ill the spring (Stolle et a!. 1993). 111is resulted in a range conditions prior to calf binh (snow propenies), and late spring, cool SUIlUllt:r, early and heavy snow the proportion of calves horn in coastal plain or foothill deposition in the fall, and ncar catastrophic conditions for ,",ones. caribou. Analyses of the proportion of calves surviving in We sunnise tllat the consistently bad weathcr relation to these independent variables were conducted conditions during 1992 and early 1993 resulted ill a carry scparately :"It 2 scales: a) the extent of calving and b) the over effect t1Klt reduced calf sun'ival in 1993 to levels annual calving grounds. much lower than would havc been expectcd on the basis Within the extent of calving, the relative amollnt of of NDVl_621 alonc. It was likely that this suspected forage available to females during peak lactation additional mortality in 1993 affected calves within the (NDVL621) provided the best mouel of calf sun'ival first day or two of life; perhaps many calves were of very during June (r = 0.85, l' < 0.0(1) (Fig. 3.26). No otller low binh wcight. We draw this conclUSion because 0- to independellt variable that was considered added 3-week weight-gain of calves that sun'lred to be radio~ significanl explanatory power. collared ill 1993 was as high as any other year (Fig. 3.23) This model (Fig 3.26) (Percent JUlie Calf Survival = and the weights of parturicnt females Ihat were caught 10.107 + (2.U:) • NDVUi21 in the extent of calving)] ~ with their live calvcs on -21 Junc in 1993 were as high as JOO) was the best available cstimate of survi\'al of calves any weights we observed, 1992-1994 (Fig. 3.25). during JUllC for the Porcupine caribou herd under At the smaller scale of the annual calving grounds, the undisturbed conditions during the past 2 decades. '111is proportion of Porcupine caribou herd c:llves that survi\'ed model ofcalf sun'ival was independent of annual calving through June was positively related to both NDVC621 in ground location and, if the 1002 Area is developed, the the annual calving grounds and to the proJlortion of calves that were born all the coastal plain (assumed lower 28 BIOLOGICAL SCIENCE REPORT USGS/ORD 2002-0001 predalion risk) (r = 0.70, P < 0.00l). No other vari;lble predation on calf survival, it is imperative 10 specify the added significant explanawf)' power. Median NDVI_62I scale of analysis, and nssess multiple scates in lile annual calving grounds and the propof1ion ofcalves simultaneously. born on lhe coastal plain were nOl correlated (P> 0.94). 'nle temporal increase in forage during peak laetalion Forage in the 3Jlnual calving ground accQullled for (NOV,-62I ) (Fig. 3.4) was coincident with local climate approximately 75% of the total variance explained by this warming (Fig. 3.3a). Forage at calving (NDVCcalving) model and assumed pred:llion risk accoullled for the was positively associated with the Arctic Oscillation (Fig. remainder (Fig. 3.27). 3.6). TIlere were also pOsitive relationships between TI1US, in addition to scale dependcncy in the functional climate and NDVl3alving, between Jlercent of females response M caribou lo habilats (sc!eclion of NOVIs calving in the 1002 Arca and NOVI_calving, and between within the extent of calving and within the annual calving calf survival alld NOVI_calving [t..l = 0.33, P = 0.011 grounds), there was scale dependency in the numerical (annual calving ground); r = 0.60, P < 0.001 (extent of reSJlonse of calfsurvival to calving ground location and calving)]. As a result, June calf sllrvival was weakly habitat conditions. Only forage \\,;15 related to calf correlated (r = 0.22, P =()'029) with the proponion of surviv;ll at the l;lrgesl spatial scale (extent of calving) thal cows that calved in the 1002 Area. Further, because IVe :lnalyzed. climate affected calving ground location (e.g., Porcupine At the intermediate scale (annual calving ground), caribou herd females were more likely to use the western Corage dominated calf survival, bul predmion risk added pOf1ion of the extem ofcaldng following winlcrs with a iubstantial explanatory power. Attlle snlal!est scale positive Arctic Oscillation), both forage availability and individuals within the population of calves), spatial and predalioll risk were implicitly related to climate. emporal v:lriance in calf density (indirect predation risk) In YC;ITS with substantial Sllowcovcr on the coastal md direct pred:l!iOll risk 1I10st effectively explained calf plain (Fig. 3.18) and rekuively low NDVI_62I in the urvivaJ. extent of calving, average calfsurvival (66%, /l =7, SE = TIlis scale dependency ill calfsurvivallikeJy occurred 690) was 19% less (P = 0.0(8) than when there was little 'ecause the annual vari:lllce in habit:ll conditions in both S!lOWCOVer at c:Jlving and NDVC621 was high (85%, fl = he eXlcnt ofcalving and in the annual calving grounds far 6, SE = II %). Thus, climate was an important influence xceeded the annual variance in predation risk within the on habitat conditions, on tile likely lise of the Alaska xtcnt of calving and \vithin thc annual calving grounds. coastal plain and 1002 Are;l for c;llving, and on calf 'he scale dependency in caIrsurvival made it impossible survival during June, 1983-200 I, ullder undisturbed ) extr..lpolate across scales. Thus, 10 develop an conditions. nder$landing of the relativc influence of forage and Potential Effects of Development on June Calf Survival In ordl'r to assess the polelllial cffecl.~ of devdopllletll of the 1002 Arca on thc Porcupine caribou herd during calring, we needed a model of caribou behavioral response to oil field infrastruclilres. 'I1le adjacent Central Arclic herd (Fig. 3.2), which calved in lhe vh;inity of Prudhoe Bay - Kupal1lk complex of petroleum development arcas. provided lhc only available model of caribou behavioral response to petroleum de\'dopmelll during calving. PIlr{/lrielll ji.'IIIll!e caribou (i.c., those about to givc binh or accompanied by very young calvcs) of the Celllral .·\rclic herd repeatedly Jemostraled their scnsitivity to Jislllrb;lIlce during the first few wed;s of life of lheir cain's (Smith arld Cameron 1983, Whittcn and Cameron ure 3.27. Predicted calf survival for the Porcupine caribou herd, 1983, /)au and Cameron 19~6: Cameron et al. 191)2; \5-2001, in relation to median Normalized Difference vegetation Ndlemann and Came['{)11 19%. 1998). ex on 21 June (NDVU21) within lhe annual calVing ground and 10 Parturient fcmales ;l\"oided, \)l" wcre k.~s likely to proportion of calves bom on the Arctic National Wlldl'lfe Refuge cross. inji'ilSlntt'llires (roads and pipelines) during the sIal plain physiographic lone where predator densily \'las lower calving SeaSl)lj (Cameron and Whillen 1979, D:lIl and 1in the foothill-mountain physiographic zone (r"::: 0.696, P < Cameron 1986. !\IUfphy and Curatolo 19H7, Ll\vhcad )1). Calf survival was nol estimated in 1986 because inclement 1988, Cameron et ;iI. 1(92). In ;ldditioll, densities of ,lher prevented a complele sample in lale June. ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUMMARIES 29 caribou during calving (June) were gre curves suggest exponential growth, 2) both herds have Fourth, because thl: Central Arctic herd obtained a relatively high bull:cow ratios (-80: 100),3) calving relatively sma]] proportion of its annual nitrogen budget ground habitats of both herds showed similar climate from its calving ground compared with other herds (Fig. trends (Kelleyhouse 2001, Wolfe 2000), 4) both herds 3.22), the Celllral Arctic herd calving ground may have exhibited the same dip in herd size during the rnid-1990s had less relativc value to herd performance than the (Fig. 3.9), 5) neither herd has consistently demonstrated calving grounds of other herds. lhe long distance migrations exhibited by the Western Fifth, calving ground density of the Central Arctic r\rcric herd and Porcupine caribou herd, and 6) before herd has been, and remains, quite low (npproximately 1987, both components of the Central Arctic herd as well one-fifth thl: effective density of the Porcupine caribou lS the Teshekpuk Lake herd calved in wet coastal habitats herd; Whitten and Cameron 1985). 'nms, even though Nith relatively late snowmelt. females of the Central Arctic herd in the developed zone The apparent divergence in the relative sizes of ~Ie shifted their concentrated calving to an area with reduced ::entral Arctic herd and adjacent lcshekpuk Lake henl total forage, the amount remaining per caribou may have lrter 1987 (Fig. 3.9) suggests that the growth r;He of the heen sufficiellllO accotnmodmc nutritional requirements. ::elllral Arctic herd may have slowed after roads and Because ecological conditions for the Porcupine lipeIincs expanded in the developed zone and the caribou herd are substantially different than for the oncentrated calving area in the developed zone shifted Central Arctic herd, il is unlikely that all these outh-southwest. The relative trajectories of the 2 herds' ameliorating factors will apply to the response of the Towth curves were par single hypothetical development scenario presellted in the 1987 Finnl Legislative Environmental Impact Statement (Clough cl aJ. 1987). The scenarios in Tussing and Haley (1999) lave increased displaced calf survival by only about O.6S-;' may increase and the ;llllplitude of herd size Ill[lY be In average. lllis probably constituted the maximum affected. lossible C£fect of treating areas and calving sites thai The best empirical tool available for detecting t"crc displaced to the BC[lufort Sea as missing dat[l. potential effects of development is the modeled Stochastic simulation modeling (Walsh et al. 1995) relationship between calf sun'ival ;lIld forage for females ldicatcd that a 4.6% reduction in Porcupine caribou herd during peak lactation demand (NDVI_62l) within the alf survival during June, all else held e(lual, would have extent of t"[llving (Fig. 3.26). This model is independent cen sufficient to halt growth of the Porcupine c[lribou of actual annual calVing ground location and encompasses crd during the best conditions observed to date. A lO-km a ne[lr full cycle of herd size [IS well as subsl[l/lti[ll \'erage displacement in our simulations would have been variation in hemispheric we;lther patterns (Fig. 3.5) and Jfficient !O bring the upper confidence itllerval on the varbtion in calving ground location (Fig. 3.13). lean effect below a 0% predicted change in calfsurvival With industrial development, if observed c;tlf survival 'ig. 3.28). A mean displacement of 27 klll in our falls below the lower 95{;~;' confidence limit Oil the :odeled prediclion.~ would have been sufficient to reach predicted observations from this Illodel (Fig. 3.26), or if a iC threshold of 4.69(· Illean reduction in calf survival parallel pattern of calf surviv:ll yields a significantly lfficielll 10 halt growth of the Porcupine caribou herd lower inten;ept term, then an el"fect of development on lder best observed growth conditions 10 date. This latter calf sun'iv[l! would be indicated. vel of displacement could occur well bdorc full Individual observations til[lt fall below the lower ·.velopmellt of the 1002 Area. confidence limit and which call be satisfaelorily explained The estimated effect of displacement of the Porcupinc by exceptional environmental characteristics (e.g., carry ribou hen! Oil c[llf survival during June was over effects of ncar-catastrophic conditions in 1992 to ·nserv:ltive for several reasons. First, we used the 1993 after eruption of I\f\lunt Pinatubo) (Fig. 3.26) need nservativc estimate of a 4 km displ[lcelllent I)f not be considered evidence for effects of developmellt on Jlcen1rated calving areas from infrastructure (Callll:fOn calfsurvival. A pattem ofobsen'ed calfsurvival below al. 1992) vcrsus 7-8 kill (Wolfe 2000). Second, we the lower confidencc limit would be cause for cOllcen!. Iplaced tlle concentmted calving ;lreas parallel to the Statistic[llme!hods for making these types of decisions 'aufon Sea coastline lll\ls maimaining calving are currently in development (Rexstad and Debevec :tributions on the bes't remaining coastal plain habiWI 2001). l1tis assessmcnt will require continued intensive :I minimizing displ[lcement into the foothills where cal ving ground sun'eys and calf sun'ival estirn:l1es. ~dation would be expected to increase calf lllortality. lally, relatively low density calving was allowed to Conclusions :rlap developed [lreas, as has been observed for the ncent Central Arctic herd (Wolfe 2000, Lawhead ;lIld Our research has shown that the Porcupinc caribou chard 20(1). herd has signific:lI1t annual variance in calving ground Because the a;;sumptiolls were conservativc, IlIC location (Fig. 3.13), f[lces annual vari;lIlce in habitat ults were conservativc. Su!lstanti[ll (10 to 27 km) conditions, selects areas willI abulldall! high quality placemeJlt of concentmtcd calving areas and associated forage for calving. has incre;lsed MIn-ivaI of calves born lUal calving grounds and calving sites of thc Porcupinc in the concentrated calving areas, alld shows a con'clation ibou herd i.~ likely to negatively affect calf surviv;11 between calf survival and both forage for females during ing JUlle. At tIle upper cnd of this range of peak lactadon ant! predation risk in the annual calving Jl[lcement (27 km), recovery of the herd from the grounds. All this implies that unrestricted ;Jccess to annual [ellt decline (Fig. 3.8) would be unlikely. These calving grounds and concentrated calving areas elusions are consistent with those found in the 1987 maximized perfoonallce of lactating Porcupine caribou II Legisl[ltivc Environlllentallmpaet Statement herd females and their c[llves. Becausc the Porcupine )Ugh et a!. 1987). e:lriboll herd has shown limited c;lpaclty for growth, frel: The Ilorcupine caribou herd has demonstratcd access to calving ground habitats lIlay have compensated ,tantiainaillral variability in size alld demography for less than oplimal wintering h;llJitats. os. 3.5, 3.8, 3. IOIl"C). Because developllll~nt of the Location of the conceillrated cal ving areas during the 2 Area would take time, any cll"ec!.~ on the herd's pas! 19 years (1933-2001) is the best estimatc of thc arca 'ornl:lncc may take (kcadeS to detec!. Reduced calf that has provided the highest qualit)' calving habitat for iralmay slow the rate of increaSe during positivc females and their calves. Calf s\lfvival within !he ;es of the growth cun'e of the herd and increase the aggregate eXlem of conccntrated c;l1ving arcas has been of decline during !he negativc phases of the herd's higher (han fllr cal res born in [lreas never used as a I,th curve. The period of natur;ll cycles in herd size l:OIlCelllralcd calving area (83.8'_';~ vs.7J.9'/;', respectivdy, ARCTIC REFUGE COASTAL PLAIN 'TERRESTRIAL WILDLIFE RESEARCH SU!'IHvlARIES :n femalc weights. and 3) parturient female body condition sC(Jres during peak lactation. 1992-1994, suggcst substantial contribution of the calving ground 10 parturielll females' lllllritional status. Bccause fall wcights of panurient females influenec their probability of conception {Camcron et ai. 1993, C:lmeron and va Hoef 1994, Russell et ;11. 1(98). c:tlving ground habitats may contribute 10 parturition rmcs in the following year. " Petroleum developmcnt will most likely result in CJ.."""'" 1111.'0' .-.",,,,,,,. , ....., []""""." .."., '" '<*':''''''''''0 ..,,,..,. ,... _" restricting the location of concentratcd calving areas. -OC'...... O, ....'"""'0 "OCOO>< 1.,,:00"'" c:llving sites, ,lIld annual c:llving grounds. Expected ,..,url C}.." ...... ".,."LOOI cffect~ .. ,_..'.."'00.1"'...0'0"''''.....' that could be observed include reduced surviv,ll of calves during June. reduced weight ,lIld condition of \, ,. , " parturient females :md reduced weight of calves in late June, ,md. potentially, reduced weight and reduccd probability of conccption for parturient fcmales inthc Figure 3.29. Aggregate extenl of annual calving (light green shading) fall. and aggregate exlenl of cnncentrated calving (dark green shading) for Whether these factors :lrc additive to annual the Porcupine cariboU herd, 1983·2001. The deformedlundelormed performance or arc compensated on wimer range will geological boundary is discussed in USGS Fact Sheet FS-028-01 determine the nct value of the annual c:llving grounds 10 (U,S. Geological Survey 2001), herd performance. Detcnnining the additivcJ compensatory nature of allnual calving ground value, 19l-:3-1994, p:::: 0.026). 'nlUS, the aggregate extel1! of all through field and simulation studies, should be the fir~t observed concentrated calving areas (Fig. 3.29) identifies research priority in future work the most valuable portion of the extent of calving in terms Still unclear is the cause of the decline of the of calf survival during June. Porcupine caribou herd (Fig. 3.8) during a period when Our [llOdel prediction of ,I reduction in calf survival calving ground habitat conditions were favorable as a when calving, g,rounds were displaced supports the result of summa warnling. Increased winter JllOrtal ity was concept that caribou made a critical "decision" in locating implicated by the herd decline because sub-adult and their annual calving grounds within the extent of calving. :ldult mortality on the c;llving ground has been 19:-:3-2001. It appears that actual calving ground location ineonscquenti,l1 (Fancy et:ll. 1994, Walsh et al. 1995), maximized June calf survival given the habitat conditions ,wd parturition rate and calf survival during June has within the extent of calving for a given year. remained high during the decline. Weight-g,lin of calves provided further evidence for Possible mechanisms for this suspected increasc in ',he import:lnee of unrestricted localion of ,1I11lual calving off-calving-ground mortality include: I) reduced grounds. The lack of a relationship IJl?tween calf wcight IOIl"evitv or adult females as a result of the cumulative ~ - ~~;lill and habitat usc within annual calving grounds cncrgetic costs of persistem high parturition and calf s\I!:\!ests that weight-gain was optimized by selection of survival during climate warming. 2) incre;lscd energetic th~ ~Innu In summary, 4 research-based ecological arguments Strong link between ca/(suITjva{ nnd free wQl'emenr Idicatc that the Porcupine caribou herd may be n((ema1cr - TIle location of the llilnual calving anicularly sensitive to development within the 1002 grounds and concentrated calving areas was ;::ll1ion of the calving ground: variable among years in response to variable habitat conditions and was oftcn coincident with tva' nnJiill({;vjrv Q(rht' Pnrrwi!lf Cllri!JQII herd -111e the 1002 Area, Empirical relationships between Porcupine cnribou herd has had the lowest c:lpacity calfsurvival, forage nv:lilable to fcmales in the for growth among Alaska barren-ground herds annual calving grounds, and predation risk derived (Porcupine caribou herd = 4.9%, Central Arctic frolll 17 years of ecologiclll data predict that lunc herd =10.8%, Teshekpuk Lake herd =13'70, calf survival for the Porcupine cnribou herd will Western Arctic herd = 9.5%) :lnd is the only decline if the calving grounds arc displaced, and barren-ground herd in Alasb known to be in that the effect will increase with displacement decline throughout the 1990s. lllis low growth rate disl:lncc. This prediction (Fig. 3.28) is a function (Fig. 3.9) indicMes that the Porcupine caribou herd of displacement: I) reducing accesS 10 the highest has kss capacit}' to accommodate anthropogenic, quality habitats for f(mlging and 2) increasing biological, and nbiotic stresses than other Alaska exposure to risk of mortality from predation during barren-ground herds. Any absolute effect of calving (lirst 3 weeks of June). development would be expected to have a larger relative effecl on the Porcupine cariboll hcrd than References on the olhcr herds. For examplc, an approximatc 4,6t,1> rcduction in calf survival, all elsc held equal, Akaikc, H. 1973. Inforlllntion theory, an e.'tension of the would be cnough to prcvcnt Porcupine caribou nl:l.,imumlikclihood principle. P~ge.s 267-281 in B. N. herd growth under the best conditions obserwd to Petrol' 3.nt! F. Csaki, editors. Second International Infonll~tiol1 date (Walsh et al. 1995) or prevent recovery frolll Symposium on Theory. Akademiai Kaidi, Budapest, Hungary. the current decline. A similar reduction in calf Allaye-Chan, A. C. 1991. Physiological and ecologic;ll survival, all c1sc held equal, for other Alaska determinanlS of nUlrienl panitioning in caribou and reindeer. bnrrell-ground herds, howcvcr, would not bc Dissenation, University of Alaska, Fairbanks, Alaska, USA. sufficient to arrest their growtll. Baglio, J. V, and E. \V. Holroyd, Ill. 1989. Methods for operalional snow cover area mapping using the adv:lIlced lk/lltl1l Hr __•and J. Vcr Hoef. 1994. Predicting parturition rale of __.1995. Aggregation and migration by grazing ungulates caribou from autumn body mass. Journal of Wildlife in rel:ttion to resources and predators. Pages 257-273 in A. t-.hnagclllcnl 58:674-678. R. E. Sinclair and P. Areese, editors. Screngeti II: dyn;lmics, __, and K. R. Whiucn. 1979. Seasonallllovemenls and management ;lnd conservation of an ecosystem. Unh'ersity sexual segregation of caribou dctermined by aerial survey. of Chicago Press, Chicago, JIIinois, USA. JOtInl:l1 of Wildlife ~lanagemenl 43:626-633. Gtrllal1, K. L., R. G. White, R. D. Cameron, and D. E. Russell. __, and __,1980. Nutrient dynamics of caribou forage 1996. Body composition ~ll1d nutrient rcscn'cs of arctic on Alaska's Arctic Slope. P;lges 159-166 in E. Reimers, E. caribou. C:tnadian Joumal of Zoology 74:136-146. Gnare. and S. Skjcnllcbcrg, editors. Proceedings of the Groisman, P. A., T. R. Karl, and R, W. Knight. 1994. Observed Second Illlcrnalional Reindecr/Carihou Symposium, Roros, impact of snow cover on the heat balance and rise of Norway. 1979, Directorate[ for vilt og fcrskv:ull1sfisk, cOlllillenlal spring tempcralUres. Science 263:198-200. Trolldhcirn, Norway. Gro~s, J. E., L. A. Shipley, N. T. Hobbs, D. E. Spalingcr, and B. I Chan-IvIcLcod, A. C. A., R. G. White and D. F. Holleman. 1994. A. WU!lder. 1993. Funelional response of herbivores in Effects of protein ;lnd energy intake, bod)' condition, and food-concentrated patches - tests of a Illechanistic model. I ~eason on ll\llnent panilioning and milk production in Ecology 74:778-791. caribOll and reindeer. Canadian ]ourn:ll ()f Zoology 72:~n8 Hamilton, W. D. 1971. Geometry for the selfish herd. Journal of 947. 11lCorelical Biology 31 :295-311, __, __, and D. E. Russell. 1999. Comparative body Hare, S. R., and N. J.lIfantu:l. 2000. Empirical evidence for composition strategies of breeding :lnd nOll-breeding female North Pacific regime shifts in 1977 and 1989. Progress in I caribou. Canadian Journal of Zoology 77: 190 1-1907. Oceanography 47: 103·145. Chapman, W. L, and J. E. W:llsh. 1993. Recent variations of sea Ilaukioja, E., and R. Salovaara. 1978. Summer weight of icc ;Ult! air temperatures in high latitudes. Bulletin of the reindeer (Rilllgifa laralldll.l) calves and its irnponance for American Meteorological SocielY 74:33-47. their future survival. Repans of the Kevo Subarctic Clough, N. K., P. C. Patlon, and A. C. Christensen, editors. Research Stnlio!l 14: 1-4. 1987. Arctic National Wildlife Refuge, Alaska. coastal plain Ilellc, T., and L. Tnn·ainen. 1984. Effecls of insect harassment resource :lsseSsmcnt - report and recomll1end;ltion to the on weight g;lin and survi\'~t1 in reindeer calves. Rangifer Congress of the United States and final legislative 4:24-27. cnviroumelllal impacl statement. U.S. Fish and Wildlife Holben, B. N. 1986. Characleristics of maximum-value SCf'.'ice, U.S. Geologie-II Survey, and Burcau of Land cQmpo~ite images fWllllemporal AVHRR data. Intemational Management, WaShington D.C., USA. Joumal of Remote Sensing 7: 1417. Cronin. M. A., S. C. Amstrup, G. M. DUfner, L. E. Nod, T. L. Hope, A. S .. J. S. Kimball, and D. A. Stow. 1993.111C McDonald, and W. B. Ballard. 1998. Caribou distribUlion relationship between tussock tundra spectral renectancc during the post.calving period in rebtion to infr;lstrucluTe in propenics nnd biomass and vegetation composition. the I'mdhoe Bay oill1eld, Alaska. Arctic 51 :85-93. Intemational Journal of HeT110le Sensing 14: 1861-1 874. .. ,, , W. B. Ballard. J. D. Bryan, B. J. Pierson, and J. D. Houghton, J. T., L. G. Mcira Fihlo. B. A. Callender, N. Ham, A. McKendrick. 1998. Northern Alasb oil fields ;md caribou: a Kanenherg, and K.1I1askell. 1996. Clim:ltechange 1995: C()11l111elllary. Biolol~ic:l1 Cmlscrvalion 83:195·208. the science of climate change. C:llllbridge University Press, Curatolo, J. A., alHJ S. M. Murphy. 1986. The effects of Cambridge. England, United Kingdom. pipdines, mads, and tramc on the movel1letl!s of caribou. Johnson. D. H. 1980. The comparison of usage and availability Rimgifcr lilfilndlls. Canadian Fiehl·Natur;llist !OO:218·224. measurements for cvalualing resource preference. Ecology Dau, J. R., and R. D. Cameron. 1%6. Effects of a HJ:J.d system 61 :65-71. on caribou oJistriblllion during calving. R:lI1gifer. Special Jorgenson. J. c., P. E. Joria, T. R. 1\IcCabe, B. R. Reitz, M. K. Issue 1:95-101. Raynolds,lIl. Emers, M. A. Wilm.~. 1994. Users guide for Duquellc, I.. S. 1984. Pnll,~ms ofactivity and their implications to the land-cover ll\;IP of the coastal plain of the Arctic lhc ,'nergy budget of migr;lting caribou. Thesis. University of National Wildlife Refuge. U.S. Fish and Wildlife Service, Alasb, Fairbanks, Abska. USA. Fairbanks, Alaska, USA. Fancy, S, G.. L. F. Panko K. R. Whitten. and W. L Regclin. Kelleyhousc, H. A. 2m)!. Calving ground selection and fidelity: 1989. Seasonal mO\'eillcnts of caribnu in arclic Alaska as Westem Arctic aml Teshekpuk Lake herds. 'nlCsis, oJctennined hy .~atellite. Canadian Journal of Zoology University of A!:lska. Fairbanks. Alaska, USA. 67:644·650. KUTOpat, P. j, 1984. Foraging behavior of caribou on a calving ___' :Illd R. G, While. 1987. Energy "xjlenditllfcs for grOlllld in Nonh\\'e.'itcrn Alaska. Thesis. University of 10coillolinll hy harren ground carihou. C,llladbn JOllfllal of AI:I'ik:l. fairbanb. :\Ia~k:t, USA. Zoology 65:122· 128. L"lngvatn. R., and T :\. Hanley. 1993. Feeding-patch choice hy __. and K. R. Whitten. 1') __•L C Byrne. :lnd C B. Johnson. 1993. Caribou Paruelo, J. 1'11 .• B. E. Epslein. W. K. Laucnrolh, and I. C. Burke, Synlhesis: 1987-90 Endieoll environmentalmoniloring 1997. ANPP eslimales for NDV! for lhe ccnlfal grassland program. Ullpublished report sponsored by U.S. Army region of lhe Uniletl Slales. Ecology 78:953-958. Corps ofEngineers, Alaska District, Anchorage. Alaska, Pollard, R. B., W. B. Ballard. L E, Noel, antl M, A. Cronin. USA. 1996. Surnmer dislribution of caribou, Rangifcr tarmrdus ___, and A. K. Prichard, 2001. SUf\'eys of caribou :llld gran/i, in lhe area of lhe Prudhoe Bay oil field, Alaska, muskoxen in lhe Kuparuk-ColvilJc region, Al:lska, 2000. 1990-1994. Canadian Fic!tl-Naturalisl 110: 659-674_ Final Rl'port for Phillips Alaska. Inc., prl'parcd by ADR. POSI. E., and N. C. Stenselh, 1999. Climalic variabilily. planI Inc., FJirbanks. Alaska. USA. phenology, and nonhern ungulales. Ecology 80: 1322-1339. tllalingreau,1. P.• and A. S. Ilc!w;lfd. 1992. Scale consideralions __, __. R. Lang..:lIn, and J. Fromentin. 1997. Global in vegelation monitoring using AVHRR d:lla. Intern:llional climate change and phenolypic varialion alllong red deer Journal of Remole Sensing 13:2289-2307. col IOns. Proceedings of lhe Royal Society of London. ?\larkon. C. J.,I\l. D. Fleming. :Illd E. F. Dinian. 1995. Series B 264:1317-1324. Characterislics of vegelJtion phenology over the Alaskan Rexslad, E. A .. and E. Debe\'ec. 2001.1I1lerislic melric for landscape using AVHRR lime-series data. Polar Hewnl ecological I!lonil\)ring. PapCf presentcd atlhe Annual 31:179-190. Meeling ofllie Wildlife Sociely. 28 Seplember, 2001, Reno. Maxwell. B. 1996. Recelll climale paltcrns in lhe Arctic. Pages Nevada, USA. 21·46 in W. C. Deche!, T. Callaghan, T. Gilmanov, J. I. Roffe, T. J. 1993. Perinalal IlIonality in cariholl from the Hollen, D. M;l.,well, U. Molau. and B. Sveinbjornsson, Porcupine herd, Alaska. Joum:l1 of Wildlife Diseases edilors. Global change 'lIld arclic terreslrial ecosyslems. 29:295·303. Ecological Sludies 124, Springer Verlag, New York, USA. Hussell. D. E., K. L. Gerhan, R. G. While, and D. van de Mielke, P. w., and K. 1. Berry. 1982. An eXlended class of Welering. 1998. DeleClion of early pregnancy in caribou: penmJlation leclmiques for malched pairs. Communicalions evidence for lael:llional infertilily. Journal of Wildlife in Slalislics: Theory and Melhods II: 1197-1207. Managemelll 62:1066-1075. Minnis, P.• E. F. Harrison, LL Slowe. G. G. Gibson. F. M. __, A. M. Marlell. and W. A. C. Nixon. 1993. Range Denn. D. R. Doelling, and W. L. Smilh, Jr. 1993. Radiative ecology of lhe Porcupine caribou herd in Canada. Rangifer dimate forcing by the MOlllll Pinatubo enlption. Science Special Issue 8. 259:1411-1415. __, and R. G. White. 1998. Surviving in the north· a Murph)', S.M.. 'lUd J. A. Cur:uolo. 1987. AClivity budgets :llld eonceplUal model ofreprodUCliYe stralegies in arclic 1l10velllezll rales of euiboll encoulllenng pipelines, roads, carihou. Proceedings of lhe Eighth North American Caribou and lraffic in Iwrthem A[;lsI: I Smith, W. 1'., and R. D. Cameron. [983. Responses of caribou __, F. L. 13unndl. E. Gaarc, T. Skogland, and B. Huben. [0 industrial development on Alaska's Arclic slope. Acta 1981. Ungul:ltes on arctic ranges. Pages 397-483 in L.C. Zoologica Fellic:! 175:43-45. Bliss, O. w. Ik:ll, and 1. J. Moore, editors. Tundra Spalingcr, D. E, T. A. Hanley, and C. 1'. Robbins. 1988. ceo$ystems: a compar:lti\'e analysis. IrHemational Biological Analysis of the functional response in foraging in the Sitka Program 25. Camhridge Universit)· Press, Cambridge. black tailed dca. Ecology 69: 1166-1 J75. England. United Kingdom. I Sp:lrks, D. R., and J. C. Malcchck. 1968. Estimating ,l<:rccnlagc __, ,lf1t! J. R. Luick. 198-1. Plasticity and constraints in the dry weight in diets using a microscopic [cchniljlle. Journal !:lctation:J! strategy of reindeer and caribou. Symposium of of Range M:ll1agcl11cnt 21 :264-265. thc Zoologic:lI Society of London 51:215-232. Stone, R. S., J.lt Key. and E. G. DUllOlL 1993. Propcnics nou .._._' B. R. ·nlOmson. T. Sk!)gl:md, S. J. Person. D. E. Russell, decay uf slralOsphcric aerosols in the Arctic following the D. f. Holleman. :llld 1. R. Luick. 1975. Ecology of caribou 1991 eruptions of Mount I'in:llubo, Geophysical Research at !'mdhoc Bay. Alaska. Pages 151-201. ill J. Drown, editor. LcHers 20:2359-2362. Ecolo,gie;ll investigations df the tundra biome in the lllOlllpWll, D. C., and K. H. l>!cCourl. 1981. Season;ll diets of Prudhoe B,ly regioll, Alaska. Biologic:ll P;l]Jers. University the Porcupine Caribou herd. American l\lidl;md Nnturalist of Abska, Special Report 2. 105:70·76. ___, and 1. Trudell. 19S01l. Patterns of herbivory and nutrient __, ,wd 1. M. Wallace. 1998. The Arctic O~eiJlation intake ofrcindecr grazing tundra vcgct'llion. Pagcs 180-195 .~j£nalUrc in wintertime geopotclllial height and tempnalllre in E. Reimers, E. Gaare, allt! S. Skjcnncbcrg, editors. field,. Geophysical Resean::h Leners 25: 1297-1300. Pmceedings of the Second Intem:lliollal Reindeer/Caribou __, ;wd __. 2001. Regional climate impacts of the Symposium. Roros, Norway, 1979. Dire.ctoratet for ..ilt os Nonhem Hemispherc Annular Mode and associ:lled climate ferskvannsfisk, Trondheim, Norway. trends. Science 293:85-89. __, and __. 198Gb. H;lhitat preference and forage Toupin, B., 1. Huot, MlIJ M. Manseau. 1996. Effect of insect consumption by reindeer and caribou ncar Atkasook, harassment on the behaviour of the Riviere George caribou. Alaska. Arctic and Alpine Research 12:511-529. Arctic 49:375·382. Whitten. K. R., and R. D. Camcron. 1983. Movements of Trudell, 1., and R. G. White. 1981. The effect of forage structure col bred caribou, Rilngifa {amlltllls, in relation to petroleum and aV;lilability on food inl;lke, biting rate, bite site, ,md development Qutlle Arclic slope of Alaska. Canadian Field daily eating time of reindeer. Journal of Applied Ecology Naturalist 97: 143-1·16. 18:63-81. __, and __. 1985. Distributiol1 of caribou calving in Tucker, C.l. 1979. Red and photographic infrared linear relation to the J'mdhoc Bay oil field. Pages. 35-39 ill A. M. combin,ltions for monitoring vegetation. Remote Sensing of Mancil and D.E. Russell, editors. Caribou and human the Ellvironment 8: 127-150. activity: proceedings of the First Nor1h Americ-:lll Caribou ___,J. Y. Fling. C. D. Keeling, amI R. H. G:Ulllllon. 19l16. Workshop. Whiteholse. Yukon Territory. 1983. Canadian Relationship bCllwcn ;llmospheric CO. variations and a Wildlife Service Special Publicatillils. Ott:lwa, Ont;lrio, satellite·derived vegetation index. Nall'lfe 319: I 95-199. Canada. __, and P.l. Sellars. 1986. S,llellite reIllOte seming of ___, G. W. Garner, F. 1. Maua, and R. B. Harris. 1992. primary production. Intemationallnumal of Remote Prodnctivity ;md early calf survi\';ll of die Poreupinc c:lribou Sensing 7:1395-1416. herd. 10llnl:ll of Wildlife M;uwgemellt 56;201-212. Tussing. A. R., ,md S. Haley. 1999. Dr:linage pierces ..\NWR in Wiens, J. A. 1989. Spalinl scaling in ecology. Functional AlJska study scenario. Oil and Gas JOllmaI97:71-X·l. Ecology 3:31:\5-397. U.S. Geolog,ical SUn'ey. 200I. .·\rcljc National Wildlifc Refuge, Wilmshurst, J. allll 1. Fryxcll. 1995. Patch seleclion by red deer 1002 Area. petroleum asse.~Slllent, 1993, induding economic in lc!atiDn to energy and protein illtakc: ,l re-evahJation of analysis. U.S. Geological Survey Fact Sheet FS·02g-01 Lang,,"atn ;Illd Hanley's (I <)93) results. Oecologia 104:297 (Supcrcedcs FS-0·1O-98) April 2001. ]00. Walsh. N. E., S. G. Fallcy, 'f. R. McCabe, and L. F. 1':l/lk. 1992. Wolfe, S. A. 200n. Habitat selection by calving cariboll of the Hahi!;!t usc by the Porcupine caribou herd durillg predicted Cell1ral ,\rctic herd. 1980-<)5. 11lesis, [Jnh'ersity of Alaska, insect h:lr'lssment.loumal of Wildlife Management 56:,165· Fairbanks..·\la.~ka. USA. 473. ___, n. Griffith, and C. A. Gray Wolfe. 201JI). Re~]lonse of __• B. Griffith, and T. R. McCabe. 1995. Evaluating gmwth reindeer and carihlJll to hllnlan acti,itics. Polar Research of the Porcupine caribou herd using a stochastic Jllodcl.lourn:ll 19:6:1·73. of Wildlife Matl:lgemellt 59:262-272. Young. D. J.• and T. R. McCabe. 1997. Griuly be:u predntion __' T. R.l\IcCabe.l. M. Welker. and A. N.P:lrsons. 1997. ratcs ,m cMih,lU ca!l'"s in Ilorlhe~,tern AI;I.,LI. JOllrnal of Expc-rimelltal manipulations of snnw-tkpt!l: effects on Wildlife ~l:mag<'lllent 61: I()56·1 066. nutri,-nt conlc-nt df ,',\fibOli (llf:lg<~. Ghlb:l! Change Biolo,:y 3 Zhou. 1... C. J. Tuckcr. I{. K. Kaufmann. D. SI'lyhack. N. V. (Supplement I): 158-1 (i·I. Shnh;l!lol" :Iud R. B. lIfyll<'lli, 2001. Vari:ltion in northern White, R.G, 1983. For;lgin~ p;lttems and thdr lJmhiplicr eJfccls ,cgetation ;tctil'ity infcncd from sat,'llii,' data of vegetation ')Il productivity of northern ungulall's. Oikos ·10:377 ·384. ilHJcx durin,; 1lJ811 Section 4: The Central Arctic Caribou (Dauphine 1976, Thomas 1982, Reimers 1983, White Herd 1983, E10ranta and Niemincn 1986, Lenvik et al. 1988, Thomas and Kiliaan 1991) and survival (Haukioja and Sal{l\'aara 1978, Rognmo et al. 1983, Skogland 1984, Raymond D. Cameron, Walta T Smith, Robert G. Whitt', Eloranta and Nieminen 1986, Adamczewski ct al. 1987). and Brad Griffirh Those concerns, though justified in theory, lacked empirical support. With industrial devc!opment in arctic From the mid-1970s through the mid-1980s, use of AI:lska virtually unprecedented, there was little basis for calving and summer habital~ by Central Arctic herd predicting the extent nnd duration of habitat loss, much caribou (Rangifa tarafldlls gmnti) declined ncar less the secondary sllort- and long·term effects on the petroleum development infr:lstructure on :\I:lska's arctic well-being of a particular caribou hcrd. cO:lstal plain (Cameron et a!. 1979; Cameron and Whitten Furthennore, despite a general acceptance that body 1980; Smith and Cameron 1983; \Vhillen and Cnllleron condition and fecundity of the felllales arc functionally 1983a, 1985; Dau and C:llllcron 1986). related for reindeer and caribou, it seemcd unlikely that With surface development continuing to expand any single model would apply to all subspecies of westward from the Prudhoe Bay petroleulll development Rmrgila, and perhaps not c-vcn within a subspecies in :m::a (Fig. 4.1), concerns arose that the resultant different geographic regions. We therefore lacked a cUlllulative losses of habit:!t would eventually reduce complete underst:lJIding of the behavioral responses of productivity of the caribou herd. Specifically, reduced arctic c:lribouto industrial development. the manner in nccess of adult females to preferred foraging areas lllight which access 10 habitats might be affected, and how adversely affect growth and fallening (Elison et a1.1986; cll,mges in habit:lt use might tr:lnslate into measur:lble Clough ct:ll. 1987). in turn depressing calf production effects on fecundity and herd,growth rate. N \ , ALASKA \ MILNE PT, OLiKTOK PT. SPINE ROAD KUPARUK PIPELINE o 5 10 KILOMETERS EM~.~.'=' ==ll O••~,_~~....5===='it? MILES FIgure 4.1. Petroleum development irlfrastruclure in the Prudhoe Bay and Kuparuk peiroieuill development areas, Alaska, showing primary and secondary roads. pipelines. and gravel pads, 199~. ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RE":iEARCH SUMMARIES 39 Our study addressed the following objectives: I) that long-term trcnd, however, there was an abrupt estimate variation in the size and productivity of the decrc:lse from 1992 to 1995. This decrease coincided with Central Arctic hcrd; 2) cstimate changes in the calf production estimates at or bclow approximatcly 70%. Jistriblllion and l1lovements of Central Arctic herd Steady growth thereafter was associated with productivity caribou in rdation to thc oil ficld dcvelopment; 3) estimatcs consistcntly exceeding 70%. estimate thc relationships between body condition and rcproductivc performance of female Central Arctic herd Development-related Changes in Distribution caribou; and 4) compare the body condition, reproductive success, fUld offspring survival of females under Since 1978, changes in the distribution ofcalving disturbance-free conditions (i.e., cast of the caribou :lssociated with the Kuparuk petrolcum Sagavanirktok River) with the stmus of those exposed to development :lrC:l, wcst of Pmdhoe Bay (Fig. 4.1), have petroleum-relatcd development (Le., west of the been quantified using stri]HranSecl surveys flown by Sagavanirktok River). helicopter. After construction of a road system ncar Mi]ne Point, Status of the Central Arctic Herd mcan caribou abund:lnce declined by morc than two thirds within 2 kill from :l road and was less than Photocensus results indicate net growth of the Centml expected, overall, within 4 km; but nearly doubled 4-6 km Arctic herd from 1978 through 2000 (Fig. 4.2). Within from roads (Fig. 4.3) (Cameron et al. 1992b). Prior to road placcmcnt, caribou were found in a single, morc-or less continuous concelltration roughly centered where thc Herd Size 1\-1ilne Point Road was subsequently built. After COl1stmction of the road, a bimodal distribution with separate concentrations east and wcst of the road W:lS • clearly apparent (Fig. 4.4) (Smith and Cameron 1992), §:1 • indicating avoidance of infrastructllre by cnlving c:lribou. 'nese results suggest thai roads spaced too closely ~20 • will depress calving activity within the entire oil field x j • complcx. In fact, relative occurrence of caribou in the j lS- heavily-developed western portion of the Kuparuk <; ! • petroleum development area declined significantly from ci 10 Z • 1979 through 1987, independent of total abullll:lnce (Fig. • 4.5) (Culleron et al. 1992b) . 5· r-,- -,-, ,,,.. 1976 "" '''' "'" "" Net Calf Production '00 •• • U 20 _All carlbou ~oo• • • • • ,,' t=JCalvu U •• • C ~ • '" 00 ..~ ,C• '" • .8 • •• • ";;; ,• 70 • • C E .,0 '" ~• • • U 0 ro • ~ " • • U. -0.4 '--'-T·-·'--'-··-~-'-'-'-' <.8 " 1978i" \S'82' ,,,.. "" "'" "" ·1.2 0, , Distance Interval (km) Figure 4.2. Pholocensus estimates of lhe Cenlral Arctic caribou herd, 1978-2000 [Whitlen and Cameron 1983b; Alaskii Department of Fish Figure 4.3. Fraclional changes in mean densit ' or caribou from the and Game (AOF&G) files] and net calf production based on 1 obsel\'alions 01 radio-collared adull (i,e" sexually.mature} females Cenlral Arctic herd bet,'1een pre·construction (1978-81) and post lrom 10 June through 15 August (ADF&G files). Nole: Procuclivity dala conSlruction (1982-87) periods for 1-km·dislance intervals from the not adjusted for differences in sample sizes east and west of lhe Milne Point road system in the Kuparuk petroleum development area, Sagavanirktok River, Alaska, Alaska. (from Cameron el at. 1992b) 40 BIOLOGICAL SCIENCE REPORT USGSIBRD 2002-0001 , . ".w 90 _ All Caribou 1979-81 80 0'. ~ c:l Calves "'" e70 0 60 I, '0 .8 40 ~ 30 u• .. 20 10 0- - 79 1982·86 eO 82 83 84 85 87 ro,. " Year " '" " rlmlHl=h... ~4 • All caribou I .,....~O C Calves 0 ~ :J 1.6 '"~ l'.l 1.2 0 1987-90 ci 0.8 _,0.', c . . ,,," "'. .. ..n' .. ~ 0.4 G.. ."'-.. .. '" ...... 'D' 'a-. '&-.-0 0 79 '0 51 82 83 84 B6 87 j. Year " Figure 4.5. Decline In percentage abundance of canbou from the Central Arctic herd west of the Mitne Point Road, Kuparuk petroleum development area, Alaska (Spearman's Rank, P < 0,02), and changes in tolar numbers of caribou observed north of the Spine Road (see Fig. ".w " . 4.3), 1979·1987, (from Cameron el al. 1992b) ;t\vay from the I\lilne I\)int petroleum production unit Figure 4.4. Changes in mean relative distribution of caribou from the Central Arctic herd in the Kuparuk petroleum dovelopment area, (Fig. 4.7), apparelltly in reSponse to the increasing density Alaska, during calving: 1979-1981, 1982-1986, and 1987-1990. Shown of infrastmcturc. only are those 10.4·km2·lransect segments in which the occurrence of Ground observations within the Kuparuk petroleum caribou exceeded the area contribution to total coverage (0.9%). dcvelopmcnt area in 1978-1990 provided additional Gradations in line spacing depict multiples of observed use relative to insights on changing distribution and movements. availability: \~ide =<3X; narrow = >3X-5X; solid =>5X. {from Smith Caribou incrcasingly avoided zones of intensive activity, and Cameron 1992} especially during the calving period (Smith et al. 19(4), corroborating data from strip-transect surveys. Lower An e.'\]lonelltial decline ill the occurrence of caribou as success in crossing road/pipeline corridors by large density of roads incre:lsed (Fig. ·1.6) (Ncllemann and insect-haras.~ed groups (Smith and Cameron 1985, C;ulleron 1(98) underscores the sensitivity Ilf the females CllfalOlo and !'vlurphy 1986, l\lurphy and Curatolo 1987, dllring the calving period. The probable consequence is Murphy 1(88) may have contributed 10 a general shift reduced access 10 preferred habitats (Bishop and Cameron from Ihe central KupanJk petroleum development ;1rC:lto 1990, Ncllemann and Cameron j()96, 1993). peripheral areas with less slIfface developmcnt and human redi.~tribution Incremental anti local hahitatloss within activity. Routes of summer moyement arc now primarily tho.) Kupamk petroleulll development area may have soUlh of OliklOk Point and along Ihe Kuparuk Rivcr triggered changes on a regional scale. \VoIfe (2000) floodplain (Smith e( ;II. Jl)y.lj. reported an inland shift in concentrated calving ,lctiYity r ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUMMARIES 41 I 5 - a "~4 I .s ~ I .~ 3 c aw I ~ a 2 ~ ·0 ro () 1 o o >0.6-0.3 >0.3-0.6 >0.6-0.9 2 Road Density (kmlkm ) Figure 4.6. Relationship between mean (SE) density 01 caribou from the Central Arctic herd and road density within preferred rugged terrain, Kuparuk petroleum development area, Naska, 1987-1992. Different lellers indicate a significant difference (P < a.OS). (from Nellemann arid Cameron 1998) An analysis of the summer distribution of radio collared females in 1980-1993 (Cameron Cl al. 1995) suggests that caribou usc of the oil field region at Prudhoe Bay has declined considerably from that noted during the 1970s by Child (1973), Whilcet al. (1975), and Gavin (l97R). Caribou abundance within the main industrial compli:x as well as cast-west movcmcnts through that area were significantly lower than for other areas occupied by caribou along the arctic coast (P = 0.001 and P < 0.001, respectively). Conservative calculations yielded an estim:ltcd 78% lkcreasc in usc by caribou and a 90% decrease in their lateralmovemcnts (Cameron ct al. l (95), all changes apparcIHly in response to illlensi ve devclopmcnt of the Prudhoe Bay to Kuparuk oil Held region over the past 3 decades. Occurrence ofcaribou that usc the complex, however, is reportedly unrelated to distance froill infrastnJcture (Cronin et al. 19(8). Body Condition and Reproductive Performance Reproductivc success of caribou is highly correlated with nutritlollal statuS. 'lllC probability of producing a calf varies directly with body weight and/or f:lt content of sexually-mature females during the prcvious alltullln (Cameron et al. 1993.2000; Camcron and Vcr I-locI' 1994; Gerhart ct A Reference Zone 0.30 P =0.2274 q) 0,25 . c · . ~ 0.20 · -~ 0.15 . 0 . : : 5" 0.10 . 0 . Z 005 · 0.00 -I-~-_---';'-_~_-'--:'-.-~ Hl80 1962 1984 1986 1966 1990 1992 1994 199tl Year B Treatment Zone 0,30 y=23.186-0.0t16x P '" 0.0001 r'= 0.30 ~ 0,15 o >- 0.10 o 1 ;~ Z 0.05 ---z.~. om •• Figure 4.8. logistic regres~ions (solid lines ale significant al P < 0.05) HMO 1982 1984 1986 1968 1990 1992 1994 1996 of parturition rale, incidence of early calving (i.e., on or before 7 June), Year 'and perinatal (>2 days post partum) calf swvwal on autumn and summer body weights of female caribou, Cenlral Arctic caribou herd, Alaska, 1987-1991. The empirical percenlages are shol'm al arbitrary Figure 4.9. Changes in median Normalized Difference Vegetation 10-kg intervals of body weight. Numbers in parentheses are sample Index (NOVI} on 21 JUrle for concentraled C I % Parturient (n) ·-...... PottunbO __, __, and W. T. Smith, and D. D. Roby. 1979. Caribou References distribution and group composition associ:lted with constmetion of the trans-Alaska pipeline. Canadian field· Ad:lfllC7_Cwski, J. Z., C. C. Gates, R. J. Hudson, and 1\-1. A, Price, Naturalist 93: 155·162, 1987. Seasonal changes in body composition of mature Child, K. N. 1973. The reactions of barren·ground c:lribou felllak caribou and calves (Rdllgifcr (ilf<1JldIiS (Rilllgifer lari1lldus gnlllli) to simulatcd pipeline and grow/andicus) on an :lrctic island with limiteJ winter pipeline crossing stmetures at Prudhoe Bay, Alaska. resollrces. Canadian Journal of Zoology 65: 1149-1157. Complelion Report, AI:lska Coopef:ltivc Wildlife Research Bishop, S. c., and R. D. Cameron. 1990, Habitat usc by post Unil, University of Alaska, fairbanks. Alasb, USA. parturient femak caribou of the Central Arctic herd. Paper Clough, N. K., 1'. C. Patton, and A. C. Christiansen, editors. presented at the annual metting of'I11c Wildlife Society. 1987. Arctic National Wildlife Refuge, Al:lsb, coastal pl(lin :\l;lska Ch;lJlter. Juneau, Alask:!, USA, ·1·6 April 1990. Book resource assessment - report and recolllmendation to thc of abstracts:9. Congress of the United States and final legislative Cameron, R. D. 1994. Reproductive p:luses bv fern:llc caribou, environmelllal illlpact statement. U.S. Fish and Wildlife J(lunlal of 1>1:lll1lJlalogy 75: 10-1 3. • Service, U.s. Geological Suryey, and Bureau of Lmd __. 1995. Can petroleum development depress the Management, \Va..shington D. C. productivity of arctic e:lribou? Paper presented at the Cronin, M. A., S. C. Amstmp, G. M. Dumer, L. E. Noel, T. L. Second International Arctic Ungulate Conference, McDonald, and W. B. Ballard. 1998. Caribou distribution Fairbanks, Alaska, USA, 1:1-17 August 1995. Bllok of during the post-c:l);'ing peri oJ in relation to infraSlmcture in ab.>lracts:36. lhe Pmdhoe Bay oil field,/\lasb. Arctle 51:85-93. _.__. S. G. Fancy, and W. T. Smith. 1992a. Reproductive Cur:llUlo, 1. A., and S. M. Murphy. 1986. 111e effects of perfoTllm}ce of caribou in relation to habitat a\':libbilit\' and pipelines, ro;lds, and traffic on llW\'elllelllS of caribou, quality. Pages 67-78 in T. R. MeC:lbe, n, Griffith, N. E~ Rangifa lamlldlls, Canadian field-Naturalist 100:218-224. Walsh, and D. D. Young, editors. Rew:lrch on the poteillial Dall, J. R., and R. D. Cameron. 1986, Effects ofa road system effects of pClrokum development on wildlife and their on caribou distribution during calving. Rangifer, Special h:lbitat, Arctic National Wildlifc Refuge interim report, Issue 1:95-101. J988-1990. Alask:l Fish and Wildlife Research Center and Dauphine, T. C" Jr. 1976. Biology of the K:uninuriak Arctic National Wildlife Refuge, Fairbanks, Alaska, USA. population of barren-ground caribou. Part 4: growlh, __, E, A, Lenart, D, J. Reed, K. R. Whitten, and W. T. reproduction, and energy rc.~crves. Canadian Wildlife Smith. 1995. AbunJance and movements of caribou in tbe Service Report Series 38. oil Held complex ncar Prudhoe Bay, Alasb. Rangifer Elison, G. W., A. G. Rappoport, and G. M. Reid, ediwrs. 1986. 15:3·7. Report of the caribou impact analysis workshop, Arctic __, D. J. Reed, J. R. D:m, and W. T. Smith. 1992/1. National Wildlife Refuge. 19·20 Nov 1985. U.S. Fish and Redistribution of calving caribou in response 10 oill1eld \Vildlife Seryiee, Fairbanks, Alaska. USA. tlevclopmelll 011 the Arctic Slope of Alaska. Arctic 45:338 Eloranta, E" :md 10.1. Niemincn. 1986. Calving of the 342. experimental reindeer herd in Kaam:men during 1970-85. __, O. E, Russell, K. L. Gerhart, R. G. White, and J. M. Ver Rangifer, Special Issue 1: 115- J21. Hod. 2(X)O. A model for predicting the parturition status of Gavin, A. ca. 1978. Caribou migrations and p:llleTlls, Pmdhoc arctic caribou. Ran£!ifer, Speeial Issue 12: 1-3. Bay region, Alaska's North Slope (1969'1977). __, W. T. Smith. S. G. F:lney. K. I.. Gerhart, and R. G. Unpuhlished report, ARCO Alaska.lnc., Anchoragc, Alaska, White. 1<)93. Calving success of female c:lribou in relation USA. to body weight. C:lIladian Journal of Zonlogy 71:-180-486. Gerhart, K. 1.., D. E. Russel1. D. V:1I1 de Wetering, R, G. White, __, :H1d 1. !"II. Vcr Boef. 1994. Predicting parturition ratc or and R. D. Cameron. 1997. Pregnancy of adult caribou carib{)u from autumn hody mass. Journal of Wildlife (RallgiJ~'r IllTamill.l"): evidence for lactational infertility. Management 58:67·\·679. Joumal of Zoology 2·12: 17 -30. __, and R, G, White, 1<)92. lmp,m:lnce of summer weight Haukioja. E., :lml R. Salo\'aar:l. 1978. SUllllller weight of gain to the reproductive sUCCeSS of caribou in Arctic Alaska. reindeer (Rililgifa lilrillliJlIs) call'"s :lnd its illlport:mce for Paper presented attlie Fifth Australasian Wildlife their fUlllrc survival. Report Ke\"l) SUbarCIl<; Rescarch l\!:m:lgelllellt Society Conference, 2·4 Decemher 1992 Slation 1·1: 1-4. Brishane. Australia. Lellyik, D" O. Grimef:iel!. ami J. Tamnes. 19HH. Selection __' :Illd K, R. Whillen. 19S0. Intluence of the tr:un;- ..\Ia,b stf:ltegy in domestic reindeer: 5. Pregnane" in domcstic pipeline corridor on the local dbtrihution of c:lrilH)u. I':lges rcimJccr ill Tnllldcl;lg C'oullty. Norway. N(;r,k ·175·-18·\ in E. Reimers, E. G:l:lre. :ll1d S. Sl;jenneberg, Landhruksfmsk. 2:151-j61. editors. l'rocl'edillgs of Ihe Second Inkrnation:ll R<,ind,'l'T1 M1I1Vhy. S. M. 1988, Caribou behavior and n)()WnJ<,nts in the Caribou Sylllposium, Rows. Norway. Direkwratct for viii Kuparuk oil field: impli\.~alions for energetic :lJld imp:lct og ferskl'annsfisk, Twndheim. Norway, analyses. Proceedings of thc Third North ..\mcrican Carib<1u \\'orkshop< Alaska Departmelll of Fish and Gmnc, Juneau, Al:\ska, US ..\. Wildlik Technic:ll Bulletin 8:19(}·21O. i ARCrIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SU/I.·H.fARIES 45 __, :llld J. A: Curatolo. 1987. Activity budgets :md Whitten, K. R. and R. D. Call1cron. 1983a. Movements of mo\'<:mcnt r:lles of caribou encountering pipelines, roads, collared c Section 5: Forage Quantity and Quality Bmoks Range mountains approach the Beaufort Sea. The displacement :lre,L cho.'ien for comparison was located to the south and east of the 1002 Area in the only [Jan of Janet C. JOI:q •.'II.\OI/, Mark S. Udt'l'it:., alld Newey A. Felix Alaska's North Slope thaI is a designated Wildemess Area. The Porcupine caribou herd has tr:lditionally used the The displacelllel1l area had topography similar 10 lhe coastal plain of th~ Arctic National Wildlife Refuge. lraditional area: a mix of rolling foothills and Ct);lsta[ Alasb. for calving. Availability of nutritious forage has plains. It lay along lhe spring migration route typiCillly been hypothesizcd as one of lhe reasons the Porcupine traversed by the Porcupine caribou herd. Female caribou caribou herd migrates hundreds of kilometers 10 reach the have calved in this area. especially during years when coastal plain for calving (Kuropat and Bryant 1980. snow melled late (Fig. 3.18). Russell et al. 1993). We gathered data at both study areas during the Forage quantity and qualit)' ;}nd the chronology of caribou calving period in early June of 1990 and 1991. snowmdt (which determines availability and phenological Fifly-five 30m x 30m study sites in 1990. and 45 in 1991, stages of forage) have been suggested as important habitat were loc:lted at the intersections of grids positioned attributes lhat lead calving caribou to select one area over r:lndomly ovcr the entire study area. We sampled during 3 ,wother (Lent 1980, White and Trudell 1980, Eastland et periods in 1990 (311\Iay-) June. 8-12June, :ll1d 19-22 al. 1989). A majorqu~stion when considering the impact June), and 2 periods in 1991 (4-6 June and 9- J3 JUlie). of petroleum devdopment is whether potential Data were collected on 4 prevalent plant species displacement of the caribou from the 1002 Area to identified in the literature as impL)rtant forage for caribou alternate c:llving habitat will limit access to high quantit), on Alaska's North Slope: ErioJl/1orum vllgil/(l/um (lUssock and quality forage. cottongrass). E. (ll/glIstiloliulII (tall eOllongrass). Cart'.\· Our study had the following objectives: I) quantify at/limitis (aqu:ltic sedgcl, and SlIli.\' pfmrijolia ssp. Jlllfdmi snowmdt patterns by area~ 2) quantify relationships (diamond-leaf willow) (Thompson :ll1d !'.1cCourl 1981, among phenology. biomass, and nutrient content of Russell et al. 1993). principal forage species by vegetation lype; and 3) At each study site. for:lge quantity data were collected detemline if traditional concentrated calving areas differ in 14 I-Ill: quadr:lts along 2 randomly-located transects. from adjacent are:ls with lower calving densities in terms Phenology data were collected at the same 14 quadr:lts, of vegetation characteristics. plus 20 3-m: quadrats located on 2 additional random We investigated caribou forage in 2 areas: an transects, Tussock cOllollgrass inl10rescences and historically tr:lditional calving area entirely within the diamond-leaf willow \ca\'es were colleeled on transects 1002 Area and :In :ldjacent displacement area entirely for analyses of nLJlriel11 and fiber content at a r:lndolll outside of the 1002 Area (Fig. 5.1). subsamp\c of sites during 1990 only. 111e traditional calving area was defined during the Wc compared the tr:lditional and displacement calving 1002 Area baseline biological studies as the area of areas by measuring thc following characteristics: intensive calving use during [0 of the 14 years studied distributions of vegctiltion types, snowcover. plant from 1972 to 1985. Importance of this area was upheld by biomass, nUlri~nt and fiber eOlllen\, ;md phenology. data on calving locations from later years. Non"p:lramctric analysis of variancc using a repeated Availabil ity of potential displ:lcement areas is limited measures design was used to test for differences between here becausc the eoast:l1 plain narrows as lhe rugged the calving are:1S and between sampling periods (time). Analyses were conductcd individually for each parameter '- in each year. , ~ " " Inter,Lctions between area and tillle were tested with 1\-1anll-Whitney tests (Conover 1980) of area differenccs for each time contrast ill a full orthogonal set. If interactions were insignificant (/' > 0,(J5), area differences were tested wilh Ivlann- Whitney tests based on the Illeill\ valuc for all s:llnpling periods. The differences between the first :llld last sampling periods were tested with the sign test using data from both areas. If any inlaaetions were significant, tests for differences between areas were conducted separately for eilch sampling period, and sign tests were conducted sep:lr:ltely for e:lch arei:!. Figure 5.1. Map of c.3ribou forage sludy area. Porcupine c.3ribou herd, on the coastal plain ollhe Arctic National Wildlife Refuge, Alaska. ARCfIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUMMARIES 47 Forage Comparisons Within and Outside the uncommon at the displacement area sites. The 2 other 1002 Area sedges had very low cover and no significant differences. Diamond-leaf willow did not leaf out during the study Spring snowmelt was very e:lrly in 1990 and was period in 1991, but in 1990 willow leaves had gre(lter Ilearly complete before the calving period. Snowmelt in biomass in the traditional calving an~a when they leafed 1991 was slightly earlier than normal. In 1991, we found OUI. the traditional calving :!rea had more lIfca with partial Tussock cotlongrass flowers and diamond-leaf willow snowcover remaining during the calving period than the leavcs were tested for forage quality throughout the slUdy displacemelll area (40<;';' vs. 33%, P = 0.02). Some plallls period in 1990 (Table 5.4). Higher nutrient concentrations were in earlier phenological stages in thc traditional area increase forage quality, while higher fiber and lignin (Table 5.1). concelllrations dccrease digestibility. Both plant spccies TIle quantity of new green forage was low throughout tendcd to have greatcr forage Table 5.1. Median phenological slagesaor major forage species in the Porcupine caribou herd's lraditiorlal caribou calving area (C) and potential displacement area (D) on lhe coaslal plain of lhe Arclic Nalional Wildlife Refuge, Alaska. 1990 31 May- 03 Juno 08 - 12 June 19-22Juno C D C 0 C 0 Amab Tlmoc Tussock coltongrass 3 3" d 3 3"d 3 4.. P.:O.Ol Tall collongmss 2 2 2 2 P"O.60 " Aquatic sedgo 2 2 2 .0=0.44 .. Dlamondloaf willow 2 2 2 3.. P"O.Ol 1991 04 -06 Juno 09-13June (no sampling) r• c 0 c 0 Aroab Tlmac Tussock collongrass 2 2 3 3 P=O.85 I . • Tall collongrass 2 i P=O.04 ,i' " Aquatic sC!dge 2 2 P::O,83 "' Dloffiondtoaf willow 0 O"d 0 P.:O.Ol • P< 0.05, •• P.: 0.01, ns _ no significant dilforence. , Phenological stages: Tussock coltongrass, 1 := boot stage, 2 := early flower, 3 := lullllower, 4 := s(){)d; Tall cottongrass and Aquatic sedge, 1 := vegetatlvo .: Scm, 2 := vegetative;> SCm, 3 := early 1Iower, 4 := full nower; Diilmondleaf willow, 0 == no now grO\~1h. 1 == bud swollon, 2 := leaf unfolding, 3 := full lea" b SlgniHcallCo lovel for difference between oreas averaged over all periods. , Significance level for chango boN/eon first and last sampling period. d Phenological stage signllicanUy i'luvanced, allhough median valuos wore lhe same. 48 BIOLOGICAL SCIENCE REPORT USGSIBRD 2002-000J poorer than inlhc lower foothills of t}lC traditional calving Tabla 5.2, Medianabiomass (g/m2)and percent cover of 4major caribou forage species in the 5 mosl common vegetation types on the area. Glacial lobes covered about olle·fiflh of the foothills coastal plain of the Arclic Nalional Wildiife Refuge. Alaska. during the in the displacement area during Ihe most recent glaciation Porcupine caribou herd's calving penod. June 1990. that ended -10.000 years ago. lllese recelllly deglacialed areas have very little tussock lundra (Jorgenson 1984). VegataUon TYPesb Different distributions of veget3tiontypes may explain Illost of the differcnces found in fornge quantity and Species WG MS MSD IT ST quality bctween the traditional and displacement areas. Tussock cotlollgrass nowers had greuter biomass and .:: O.OlAlJ 0.04e 0.031lC forage quality in the tussock tundra type compared with other ,'cget3tioll types (Tables 5.2 and 5.6). The greater Tall COl1onqrass biomass of flowers in the traditional a.rea mainly resulted A1l frolllthe greater eXICnt of tussock tundra. No consistent % cover 1.2 1.4" O.Se O,4e O.Sue differences in flower quantity or quality between tussock Aquatic slX1q!) tundra in the traditional calving an~a ;llld tussock tundra in the displacement area were observed. % cover 0.9' 0.,' O.OB 0.0" O.OB The location of the Porcupine caribou herd traditional DjamQndloilf willow calvin!! area is greatly influenced by veget:llion type distributions and snowmelt patlerns across the Arctic glm~ 0.00" 0.881le O.OOJJl O.83c 3.2Sc Refuge coasl:ll plain. lllese factors appear to detennine a Values are medians for all siles. with site vatues obtained as moans for 3 times. Medians with the sarno supem::ript were the quantity and quality of forage availablc to Ule caribou nol slgnificanUy differont (P.:: 0.05). during calving. b Vegetalion types; WG ::: weI gramlnoid tundra. MS ::: moist Because of the low amount of for:lge available during sedge-wiflow tundra. MSD ::: moist sedge-Dryas tundra. IT::: tussock tundra. ST::: low shrub tundra. the calving period. the differences in vegetation Table 5.3. Median densily (no/m2). biomass (gfm 2), and percerll cover of major forage species irlthe Porcupine caribou herd's lradiliorlai caribou calving area (C) and polpnlial displacement area (0) on Ihe coastal plain of the Arctic NatlQnal Wildiife Refuge. Alaska. 1990 31 May- 03 June 08-12June 19 - 22 Juno C D C D C D Area!! Tlmeb Tussock collongrass flowers nolm2 0.6 0 0.5 0.2 0.2 0 P=0.87 "' o'm2 0.02 0 0.01 <: 0.01 0.D1 0 P=1.00 n' Tall collongrass % cover 0.' 0.4 0.6 0.3 0.6 0.2 P:::0.93 Aquatic sedge '" % cover 0 0 0 0 0 0 P=Q.72 ., Dlamondlear willoW leaves o'm2 0 0 0 0 2.0 0.3 P=O.10 1991 04 ~ 06 June 09-13June (no sampling) C D C D C D Areaa Timeb Tussock collongfllss flowers no/m2 2.7 0.0'· 3.5 0.0·· P<:0.01 n' o'm2 0.09 0.00·' 0.11 0,00·· P<:O.Ol n' Tall cottongrass % COver 0.2 0.3 0.3 0 P=O.68 n' Aquatic sedge % cover 0 0 0 0 P=Q.oa ., •P <: 0.05, •• P <: 0.01. liS no significant difference. 4 Slgnillcance levol fQr difference bel\veen areas avoroged over 311 periods. b Significance Jevel for change between first and lasl time periods. If the significance levels diflorod betwoen areas. both are shown (C/D}. , last sampling period with significantly hlghar cQvor, although median valuos were tha sarna. ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SU1'.lMARJES 49 Table 5.4. Median nlltrient and fiber concentrations {percent of dry weight) of 2 major forage species in different phenological stages in the Porcupine caribou herd's traditional caribou calving area (e) and potenlia! displacement area (D) on the coastal plain of-the Arctic National Wildlife Refuge, Alaska. Early Flower Full Rower Sow Tussock coltongrass C 0 C 0 C 0 Area a Tlmab .. .. Nitrogen 2.8 2.6 2.5 2.2 2.4 2.2 P=O.Ol "' . . Phosphorus 0.49 0,45 0,46 0.38 0.38 0.36 P:0.03 'Ins Calcium 0.18 0.16 0.13 0.12 0.14 0.11 P=0.25 "' Neutral detergent fiber 55.8 58.0 58.2 62.7 66.8 65.9 P:0.07 .. .. AcId detorgent fiber 16.5 18.4 19.0 20.4 22.8 23.2 P:O.Ol Ugnln 2.3 2.6 2.5 2.3 1.9 1.9 P==O,43 "' n (II of slles) 6 7 8 15 8 14 leaf Unfolding Full leaf Dlamond/eaf willow C 0 C 0 Nitrogen 3.7 3.4 2.2 2.2 P=O.27 Phosphorus 0.50 0.47 0.18 0.17 P=0.79 Calcium 0.51 0.49 0.62 0.59 P=Q.34 Neutral detergent tiber 22.2 22.4 25.0 25.6 P=0.71 Acid detorgont fiber 16.3 15.6 17.0 17.7 p..O.71 lignin 10.3 9.4 8.8 9.4 p,.O,43 n (II of siles) 8 8 8 8 , P< 0.05, .. P< 0.01, ns _ no significant dilference. 0 Significance lavel for difference between areas averagod over all periods. b SIgnificance level for chango between first ond last lime periods. If tho slgnifk:anco levels differed between areas, both are shown (C/O). A1ltosts for tussock cottongrass Inflorescences wara of lull flower and soed stages only. Table 5.5. Dislribulion ofvegelalion types (percent of area) in the cariboll habitlt study area (Fig. 5.1) based on an independent sample of756 systematically-located vegelation plots on the coastal plain of the Arctic National \Vildlire Refuge, Alaska. Vegetation Type Entire Calving Habitat Traditional Displacement Calving Coastal Plain StUdy Area Calving Area Area Tussock Tundra 22 30 39 21 Moist Sedge·Willow Tundra 30 25 31 19 lolV Shrub Tundra 7 11 8 13 Moist Sedge·Dryas Tundra 12 9 7 12 Wet Graminold Tundra 13 8 8 7 Dryas River Terrace 3 7 13 Riparian Shmblands 2 3 3 3 Barren 2 3 3 4 P Table 5,6, Median nutrient and fiber concentralions (percent of dry weigh!) of tussock collongrass inflorescences in different phenological stages compared oolvieen tussock lundra and o!her vegetation types on !he coastal plain of the Arctic National \'Vildlife Refuge, Alaska. Full Flower Sood n" Other n Olher Stage Nilrogen 2.4 .. 2.4 Po:: 0.01 2.0 .. 2.1 .. Phosphorus 0.43 0.34 0.39 0.35 P 0:: 0.01 Neutral detergent liber 60.0 63.6 66.2 66.7 P '" 0.25 . . AcId datergent fiber 19.7 21.8 22.8 23.6 P""0.04 lignin 2.6 1.1 1.9 1.9 P", 0.03 nlilolsiles} 17 6 16 6 • P 0:: 0.05, ··P<.O.Ol a IT '" tussock tundra; Other'" all other vegetallon typos that had tussock collongrass inflorescences lrlcluding moist sedge-willow tundra, moist sfrdge-Dl)'as tundra, and shrub-dominated tundra. characteristics found between the 2 areaS studied arc Russell, D. E., A.I\1. Martell, and W. A. Nixon. 1993. The range probably biologically impOrtillll and could affect cnlving ecology of the Porcupine caribou herd in Canada. Rangifcr, success of the herd if pctroleum development causes thc Sp.;:cial bsuc 8. Thompso!J, D. C., and K. II. McCourl. 1981. Seasonal diets of displacement of c,llving caribou Out of the 1002 Area into lhe Porcupine caribou herd. American lIfidland Naluralist adjacent arcas with lower forage valuc, 105:70·76. While, R. G., :md J. Trudell. 1980. Habitat prefaencc and References forage cunwlllplion by reindeer and caribou ncar Alk'Jsook, Alasb. Arctic :lnd Alpine Research 12(4):511-529. Conover, W. J. 1980. I'ractic:ll nonpararnctrie ~talislics. Secund cdition. John Wiley :md Sons, New York, Ncw York, USA. Easlland, W. G.. R. T. Bowyer. and S. G. Fancy. 1989. EffeclS of snow cover on selection of calving .~ile~ hy caribo\!. Journal of Mammalogy 70:112'1-828. Jorgcnson, J. c., P. E. Joria, 1'. R. l\lcCahe. ll. R. Reill., 1\1. K. Raynolds, M. Enwrs,l\1. A. Wilms. 1994. Users guide for the land·cover nwp of lhe eO:lstal plain of lhe Arctic National Wildlife RctilgC. u.s. Fish and Wildlife Service, Fairbanks, Alask:!, USA. Jor.gellson, M. T. 198·1. 'nle response of I'egelalioillo !:mdscape evulution on gl:;cial till ne;lr Tonlik L1ke, Alaska. Pages 13·1-141 ill V. J. Lallau and C. L. Kcrr, editors.lnyentorying forcst and olher veg'~lati()n of the high .-.1tilu(/c regions: proceedings of all irlleOl:uionalsymposiurn, Society of Americ:1ll Foresters Hegion.-.I Technic.-.! Conference, F:rirbanks, ..\laska, USA. Kuropat, P., and J. P. Bryant. 1980. Foraging heh:wior of COI\' caribou on lhe Ulukok calving grounds in northwcstern A1ask:!.l'agc.~ 64-70 ill E. Heimers, E. Gaare, lmd S. Skjennehcrg, ediwrs. Proccedings of the Second Inlernational Heimkcr/Carihou Symposium, Hows, Norway, JI}79. lJirekhJralCl for vill og ferskyannfisk, Trondhcirn, Norway. L<.'nl, 1'. C. 19S0. Syrwjltic ,no\I'lIl<.'h p:1l1crns in arctic ,\lasb in relation to cllribnu habi1111 use.Pag,·s 71-77 ill E. Reimers, E. Gllllre, and S. Skjenncberg, dilors. Proceedings of lhe Second 1I1tcn!atiO!lal Reindeer/Caribou Symposium. HOf()s, Norway. 1979. DirektoTaICI [(ir vill og ferskvannfisk, TroJl~heirn, Norway ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUI\IMARIES 51 Section 6: Predators use area probably existed, but were not documented in the analyzed data set. DOllald D. }Ollllg, Thomas R. McCabe, Robert Ambrose. Grizzly bear distributions were estimated annually, Gerald W Garlwr; Greg 1. Weiler; Harry V. Reyno/d.r, based on 23-60 annual locations of radio-collared bears Mark S. Udel'irJ., Dan J. Reed, Ilnti Bnui Griffith during the first week of June, 1983-1994. No grizzly bears were radio-collared in Canada. Grizzly bear habitat Calving caribou (Rallg/fer ranmdlls) of the Central use was investigated using Chi-square tests (Neu el Arctic Iwrd, Alaska, have avoided the infrastructure a!. 1974). Distance-based tests of independence (Diggk associated with the complex of petroleum development and Cox 1983) as well as analysis of variance procedures areas [rolll Prudhoe Bay 10 Kuparuk (Cameron CI a!. 1992, were used to COmpare grizzly bear and calving caribou Ncllcmann and Cameron 1998, and Section 4 of this distributions. documellt). Calving females of the Porcupine caribou herd lllay similarly avoid any oil field roads and pipelines Predator Distributions developed in areas traditionally used during the calving and post-calving periods. This may displ.1cc the c:lribou Predators (grizzly be,lrs, wolves, and nesting golden (emaIL's 3ml calves to areas cast and sOlJlh of the 1002 eagles) in general were more abundallt in 11le foothills and Area of the Arctic National Wildlife Refuge. Jllountains than on the coastnl plain (Fig. 6.1). The Increased calf mortality could occur if calving caribou distribution of grizzly bear radio-locations relative to the arc di~placed into areas that have a higher density of coastal plain, taothill, and mountain zones was 11011 predators, higher rates of predation, or where a higher f:1lldOIll (P < 0.0001, Chi-square). proportion of the predators regularly usc caribou as a food In all years, the foothills received greater usc by bears source (Whillcn et,ll. 1992). than expected, whereas the coastal plain received less use Qur study assessed predation risks to caribou calving than expected (P < 0.05), except in 1990 when the coastal in the 1002 Area versus calVing in potential displacement plain was used in proportion to its availability. We areas. Due to funding constraitlls, our research focuscd on hypothesize that bears were more :lbundant in the grizzly bears (UrSlls ilretos), with wolves (CallIIS II/pus) foothills because the rolling hills proVided greater and golden eagles (:1quila ehr)'S{1l!tos) receiving only diversity in topogr3phy, vegetation, and phenology than cursory aUention. Our research objectives were I) to the l1atter coastal plain. Other studies have reported lower t:ollljJ;lrC rcla tive ,lbundancc \} f prCtl.ltors within the 1002 grizzly hear densities 011 the arctic coastal plain th:m in Area with thai in adjacent periphcml areas, 2) to the fOOlhills of the Brooks Range (Miller et a1. 1997. I determine fat:tors :Jffecting predator abundance on the Reynolds 1979). I calving grounds, alld 3) to quantify the \lSl: of caribou as a Radio-collared wolves were more likely to be found in I food source for predators and the importance of caribou to the foothills (55%) and mountains (36%) Ulan on the the productivity of predator populations using the coa.,tal coastal plain (9%). All active wolf dens (n = 11) were I plain of the Arctic National Wildlife Refugl:. located in the 1ll01llltnins, with the exception of one den To al·curately describe the activities ofpretJators located ill the foothills. Since 1982, there havc been lIO I rdativc to calving caribou, We divided the study area into reponed cases of wolf deliS on the coastal plain of the I 3 naturally occurring physiographic zones: wastal plain, Arctic Refuge. I which included Virtllally all of the 1002 Area « 300 III All 170 golden cagle nest SlnlCIUrcs, including 22 I elevation); foothills (301-900 1lI ek"ation); and mountains active ncst sites, that were located within 30 km of the (> 900 III elevation). 1002 Area were found in thl: foothills and mountains Landscape II.~C distriblilions were estimated with fixcd (Young et al. 1995). Subadult golden eagles, howl:ver, I kernel analyses ll.~ing Least Squares Cross Validation were ,1bundant on the Arctic Refuge coast31 plain and (Silvcnnan 1986, Seaman et al. 1996, 1998, 1999). foothills where their distribution.~ coincided with those of COIlce!ltra{Ni liSt' art'as were defined as the utilization calving c:lfibou. contour that included sites with gr~'ater than average density (Seaman et;ll. 1998). In all cases, sampling was Factors Associated with Predator Distributions limited to the llonh .,Iope of the Brooks Range. Eagle distribution estimates were based on aerial .Gri~zly bear distributions during the caribou calving Stlrvey locations of 202 nest structures that \I'ere no doser penod III C;lrly June appe:lred to he inl1uenced bv a than I km from adjacent stntctures. Wolf distribtllioll combination of faclors including seasonal habit;t estimates wcre based on al:rial survey locations of 22 dens selection pallcrns, annual variations in sllOwmelt, and ill the Arctic Rclitgc and Ilnrthwcstcm Yukon lcrritorv, annual diStribution patterns of calving caribou Canada. Addition.ll \Volf dens in the foothills and . Within-year (1983-1993) spati:lI,listributio·n patterns illlmnlains to the ea.'t of tlle l'stimated wolf t:oncelltr.tlcd l)f radiO-COllared grizzly bears tJid not differ among time 5~ BlOLOGICAL SCIENCE REPORT USGSII3RD 2()(J2·(){){lJ Figure 6.1. Distribution of a) golden eagle (Aquila cllfysaeloS) nest structures, b) wolf (Canis lupus) dens, and c) griZZly bears (Ursus arc/os) near the calving grounds of the Porcupine caribou herd. Solid yellow lines enclose concentrated use areas (CUA. siles with grealer lhan average observation density). solid while lines delineate 99% use distn'bulions (UD), and the dashed red line delineates the approximate 300-m·elevalion boundary between the coastat plain and foothill/mountain physiographic lones. The ouler pen'meters of all annual griZZly bear fixed kernel estimates of CUA and 99% UD are depicted. period~, whereas concurrent distributions of cal\'ing and 1989, respectively. than in years when snowmelt caribou did differ. This suggests that annual grialy bear occurred late (12.1'.',,). as in 1988. Distributions of radio· tlislriblllions were inOuenced less by the distribution of collared bears and caribou cows with calves tended to be calving caribou than by other factors (e.g., annual positively associated in 1988 :l11d 1989 (i.e .. years of late snowmelt pallerns). Among-year differences (1' < 0.05) in and normal snowmclt. rcspectively, when calving grialy bear spatial distribution panerJls suggest that occurrcd primarily in the foothills). and negatively ;\lInual variations in snowmelt contribute 10 annual bear associated in 1990 (i.e.. a year of carly snowmelt when distribution patterns. calving occurred primarily O!1 the coastal plain) (Young et Radio·collarcd grizzly bears were relocated more a1. 19(4). frequently on the coastal plain in years when snowmelt Analyses of concurrent grizzly bear and calving occurred early (38.9%) or normally (23.S'ib), ,IS in 1990 caribou distributions in 1983-1993 indicated that bears l:I ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL W1LDLIFE RESEARCH SUl\·lMARIES 53 selected high or medium caribou density zones in 5 of 9 References (56%) years, but avoided the highest density of caribou in 2 (22%) years. Two ye:lrs were not comparable. Cameron, R. D., D. J. Reed, J. R. Dau. ;lnd W. T. Smith. 1992. During the caribou calving period, radio-collared Redistribution of calving caribou in response to oil field wolves were located primarily in the mountains and development on the Arctic Slope of Al;lska. Arctic 45:338 foothills where their activity was associated with den 342. Diggle, P. J., ;lnd T. F. Cox. 1983. Some distance-based tests of sitcs. All known wolf dcn sites on thc North Slope of the independence for sparsely-sampled multivariate spatial Arctic Refuge have been locatcd in the mountains and point patterns. International Statistical Review 51: 11-23. foothills. Thus, the avai labilily of suilable: den sitc.~ Miller, S.D., G. C. White, R. A. Sellers, II. V. Reynolds, J. W. appears to be the primary factor innuencing wolf Schoen, K.Titus, V. G. Barnes Jr., R. B. Smith, R. R. distributions during the calving period. Nelson, W. B. B(\lIard, ;"Ind C. C. Schwartz. 1997. Brown Factors affecting the distribution of nesting golden and hlilek bear density estimation in Alaska using eaglcs differed from those of subadult birds. Nesting or radiotelemetry and replicated mark-resighttechniques. adult birds sought suitable nesting habitat on cliffs found Wildlife Monographs 133. Nelkmalln. c., and R. D. Cameron. 1998. Cumulative impacts primarily in the foothills alld mounlains in proximity 10 of an evolving oil-field complex on the distribution of colonies of Arctic ground squirrels (Spermophilus parry's), calving caribou. Canadi;ln Journal of Zoology 76: 1425 their primary prey (Young et al. 1995). Subadult birds 1430. appeared to be associated primarily with distributions of Nell, C. W., C. R. Beyers, J. M. Peck, and V. Boy. 1974. A calving caribou. teehniquc for analysis of Iltilization-av:li!ability data. Journal of Wildlife !'.bnagemcllt 38:541-545. Rates of predation Reynolds, 1-1. V. 1979. Population biology, 1lI0\·ement, distribution (\nd h;lbit;lt utilization of a grizzly bear Use of caribou as a food source varied among and popul:ltion in NPR-A Pages 129-182 in Work Group 3, Studies of selected wildlife ;lnd fish and their use of habit:lts within predator species. Of 26 gri7.Zly bear observation on the l(\nds in and (\djaeent to tlle National Petroleum surveys that were stlccessfully completed (>1 hr), 8 (31%) Reserve in Alaska 1977-1978. u.s. Department of the included a kill ofa caribou calf (Young and l\kCabe Interior Niltional Pelroleum Reserve in Alask:l 105(c) Land 1997). Kill rates of caribou calves ranged from 1.0 10 6.3 Usc SlIldy, Anchorage, Alaska, USA. killslbear unit/day; a bear unit being a solitary individual, Seaman, D. E., B. Griffilh, and R. A. Powe]1. 1998. a family group, or a male with I or more consorts. KERNELHR: a program for cstimming ;lnimal home Trends in the data suggested that bears were more r:lnges. Wildlife Society Bull<'tin 26:95·100. likely to encoullIer and kill caribou calVes as calving __, J. J. Millspaugh, B. J. Kernohan, G. C. Bnlllllige, K. J. density decreased. This suggests that predator swamping Raedeke, and R. A. Gillen. 1999. Effects of s;lmplc size on kernel home r;lnge estimates. Journal of Wildlife may be an effective anti-predator strategy by calving Managemcnt03:739-7.n. females of the Porcupine caribou herd with respect to __, and R. A. Powell. 1996. An eV;llu:ltion of the accuracy predation by grizzly bears. of kernel density cstiJ1);ltors for home rangc analysis. Radio·collarcd wolves were relocated in the vicinity Ecology 77(7)2075-2085. of caribou 34% of the time and on caribou carcasses 9% Silverman, B. W. 1986. Density estinwtion for statistics and of the time. Productivity was similar (P > 0.05) between 3 data analysis. Ch(\pman and Ilall, Lond()J1, Englilnd, United lVolf packs with access (4.3 pupsflilter) and I pack Kingdom. without access (4.2 pups/litter) to the traditional caribou Whitten. K. R., G. W. Garner. F. J. M:Hwr, and R. B. Harris. calving grounds. Because there are few wolves (20-40) 1992. Productivity and early calf survival in the Porcupine and their distributions are usually separated from tho.'ie of caribou herd. Journal of Wildlife M:\Ililgel11ent 56:201-212. Young, D. D., and T. R. McC;liJe. 1997. Grizzl)' bcar predation calving caribou, wolves kilt relatively few caribou during ratc_~ on carihou calvc$ in northeastern Alaska. Joumal of the calving period. Wildlife Managelllclll 01 (.l): I056- 1060. Based Oil prey remains collected at nest sites, 1988 ___' _~, G. W. Garner. and Il. V. Reynolds, 199·1. U,.., of 1990, we observed little evidence of use of caribou by :1 Jisl:mce-oased lcst of irldcpemknce to [ll..,asurc brown nesting golden cagles. Ground squirrels were their Ilc;lr·cariblJu as,odalion in norlheaSl('rIl .-\I:lska. Ninth predominant prey (Young et at. 19(5). Subadult birds, Inlernational Confercnce of ll('ar RcsC;1fch !'.lanagemelll however, arc important pretbtOfs of cal\'illg caribou <):-135--1·12. McllllYh~. (Whitten ct at. 1992; sa (lim sCcriVlI 3 (lIth;s rqwrr). __, C. L P. J. Benle. 1'. R. l\lcCahe :mu !{. E. Amhrosc. 1995. N..,sting by goltlen eagles on lhe North Slop" of the Brooks Rangc in north<':\stcrn Alask:l. Journal 01 Field Ornithology 66(3):373-379. 54 BIOLOGICAL SCIENCE REPORT USGSII3RD 2002-0001 Section 7: Muskoxen (95% contour) were used to document changes in distribution and range expansion over time. Patricia E. Reynolds, Kenneth J. lVi/SOli, and David R. Locations ofmuskoxen sc:en during seasonal muskox Klein surveys in the Arctic Refuge, as well as locations of mixed-sex groups seen during other studies, were used to Dynamics and Range Expansion of a docuillent the Continued expansion of the population Reestablished Muskox Population distribution fromI994-200J. Reconstructed models of the population estimating maximulll and predicted population Muskoxen (O~'ibos moschatlls) disappeared from growth were used to evaluate how changes in calf Alaska in the late 1800s, but relUrned to the Arctic production, survival, and emigration affected local National Wildlife Refuge when animals were abundance of muskoxen. reestablished into areas of former range in 1969- I970 The Arctic Refuge's reestablished population of (Klein 1988). Released at Barter Island (Kaktovik) and muskoxen grew slowly for a few years and then increased the Kavik River, Illuskoxen initially moved into regions rapidly for more than a decade (Reynolds 19980). that encompassed the 1002 Area on the coastal plain of Between 1977 and 1981, the population grew at r = 0.24, the Arctic Refuge. From 1974 to 1986 the muskox a rate approaching nlilximum growth. In 1986,368 population grew rapidly. By 1987, however, numbers muskoxen were counted in the 1002 Area but after 1986 declined in the regions that they had first occupied numbers of muskoxen declined (Fig.7.1). The r:\te of ' (Reynolds 19980). increase slowed to 0.14 in 1982-1986 and to <0.00 in Petroleum e;o;ploration and develoJlment could occur ill 1987-1995. lllusko;o; habitat in the 1002 Area of the Arctic Refuge. 11le rme of population growth (r =0.14) in 1972-1996 Status of the muskox population and factors related to (Reynolds 19980) was similar to rates recorded for other trends in local abundance need to be detennined if e;o;panding populfltions of lIluskoxen in Alaska and changes resulting from natural processes arc to be Canada (Spencer and Lensink 1970, Gunn et al. 1991). separated from those that might result if industrial An introduced population of llIuskoxen in Greenland was development is permitted in the Arctic Refuge. still imlpting 25 years after release, but those animals We developed a study with the following objectives to were in an area of abundant high-quality forage with no understand the dynamics of the muskox population in and predation and low snowfall (Olesen 1993). ncar the 1002 Area of the Arctic Refuge: I) detenJline ln 1996-2001, numbers of muskoxen counted in the abundance and rates of population increase, production, 1002 Area ranged from 16810 212 (P. E. Reynolds, U.S. and survival; 2) document changes in population Fish and Wildlife Service, unpublished data) and indicate distribution over time; and 3) evaluate factors associated that muskox abundance is still declining slowly (Fig. 7.1). with changes in the number of muskoxen. Factors affecting changes in the number of muskoxen Numbers of muskoxen seen during annual censuses in in the 1002 Area of the ArctiC Refuge included changes in 1982-200 I, combined with data from earlier studies, were rates ofsllccessful reproduction and sun'ival as well ns Ilsed to estimate animal abundance and population tn::nds changes in animal distribution. of n1U.~ko:"en in the 1002 Area (regions first oecupil.'tl) Calf production was the only source of increase in this and adjacent areas to the cast and west (regions occupied reestablished population; a lack of adjaccnt populations later) (Reynolds 1998(/). Rates of.mcccssful calf producTion (defined as calves: 100 femules >2 years old present in late June), survival of calves and ye;lrlings, and long term reproduction pattem.~ by marked female llIuskoxen were determined from annual sex and age eOlllposi tion counts nl.1dc from Ihe ground in 1983-200 I. fbdio-collared auult muskoxen were relocated (j tillles!ye;lr from 1982 to 199·110 determine seasonal and anllual variability in pOJlulalioll distribution and to doculllent adult lllonalities. Locations Were determined from the air with a global positioning system (GPS) or were plotted on 1:63,360-sealc llWpS. The adapti\'e-kt~rnd 87 91 93 95 97 [19 01 technique within the computer program CALHOl\IE (Kie .11nlUYEAR et a1.19(6) was llsed to delineate the size and locations of regions used by mixed-sex groups of llluskoxen in 1969 Figure 7.1. Number of muskoxen observed in the regions first 1981,1982-1985,1986-1989. and ]l)90-199J. Core a/"ell.\" occupied after reintroduction - the 1002 Area. Arctic National Wildlife OlliSi' (70% adaptive-kernel contour) and !01II1 range Refuge, Alaska, USA, during spring censuses, 1982-2001 ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUMt1ARIES 55 of muskoxen precluded immigration. Growth of the Unlike calf production, which declined in 1983-1995 population during its most rapid increase was due to high (r= 0.75, P < 0.001), calf and yearling survival did not rates of reproduction and survival of muskoxen in newly decline over time (calf survival: r =0.01, I' =0.71; occupied habitats. In the 1002 Area, indices of successful yearling survival: r =0.01, P = 0.82). Annual variability calf production reached a maximum between 1977 and in young animal survival followed the same annual trends 1980 (87 calves: 100 females >2 years old) during years as calf production and was related 10 SIIOW depth and the when successful reproduction by some 2-year-old females length of the snow season (Reynolds 1998a). and 100% reproduction among females >2 years old Between 1983 and 1999 the percelllages of radio occurred in some groups (Jingfors and Klein 1982). collared muskoxen dying each year were variable but Calf production declined between 1983 and 2001 (Fig. showed an increased trend (Reynolds 1999). Sources of 7.2). In 1983-1986, as the rate of population increase mortality included kills by predators, including humans. begun to slow, calf production in the 1002 Area averaged Legal hUllling of muskoxen in the Arctic Refuge began 61 calves: 100 femaks >2 years old compared with 49 in in 1982. Over lime, the lIumber of permits issued ctlch 1987-1990,41 in 1991-1994, and 28 in 1995-1999 year increased frolll 5 males only to 12 males and 3 (Reynolds 1999). In June 2000 and 2001, very few calvcs femaIcs. The season was expanded from 2 to 8.5 months. «5 calves per 100 females >2 years old) were seen. An :l\'erage of 7 muskoxen was killed in 1985-1989 Because calves were counted several weeks after birth, compared with an average of 10 in 1995-1999. About 3% we could not determine if changes in the production of of the muskox population in the Arctic Refuge was muskox calves were due to lower fecundity or increased harvested annually from 1990-1999 (P. E. Reynolds, U.S. neonatal mortalities. Fish and Wildlife Service, unpublished data). Reproductive patteOls of radio-collared females in the Kills or scavenging of muskoxen by grinly bears 1002 Area showed similar trend.~. Mean reproducliI'(' (Ursus arcros) in and near the Arctic Refuge increased intervals (number of years between successful significantly between 1986 :llld 2001 (/3 =0.504. df= 18, reproductive event.~ in a 3-year period) increased I' < 0.001) (Fig. 7. 3). Known kills of muskoxen by significantly (r = 0.95, II = 6, P = 0.0009) between 1982 grizzly hears ranged from 0-2 deaths per year before and 1999. By 1991-1993, 1Il0st marked females 1993, 1-4 de:lIhs per year in 1993-1996, and 5·10 deaths successfully reproduced at intervals of 210 3 years, rather per year in 1997-2001 (Reynolds et al. 2002). than every year (Reynolds 200 1). Percentages of marked Forty-seven deaths ofadult or sub-adult muskoxen females without calves for 3 or more consecutive years from known grizzly bear predatioll occurred between were 0% in 1982-1987, 15% in 1988-1990, and 25% in 1982-2001. Of these, 28 nll1st..:oxen died during 10 1994-1996 (Reynolds 2001). In summer, body weights of incidellts of multiple kills in which bears killed more than 8 lactating muskoxen (me:lIl = 223 kg, range = 188~254 one Illuskox from a group. r-.lost of these kills (79%) lOok kg) were not different (I =2.2, df = 10, P =0.167) from S place between May 1998 and June 2001 (Reynolds et al. non-lactating females (mean = 196 kg, range = 136-254 2002). kg) and were similar to weight.~ of female muskoxen in Gri7.7.ly bears likely also killed Illuskox calvcs and other wild and captive populations (Reynolds and cau.~cd other mortal itics of young calves that were Reynolds 1999). ro ~" •• , " DMu;p"'~J~' ~ "e0 .Sir.....,kilos , • • P""iblJ 0 " • • ,"0 " • , " 15 y~.3.13JJ,.71J~'~ , " R'" () 7\38 0 , " • z " ~ g ~ § ~ ~ ~ ~ g gg g ~ ~ ~ ~ ~ ~ ~ YC~f Figura 7.2. Changes in rales 01 successful production of mus~ox calves in the regions first occupied aller reintroducliOrl-the 1002 Y"~f Area. Arctic National \Vildlife Refuge. Alas~a, 1983-2001. Successful call production was measured by countirlg lhe number of calves per Figure 7.3. Number of mus~oxen killed or scavenged by grizzly bears 100 females >2 years of age in lale June. from April 1982lhrollgh June 2001 in northeastern Alas~a. USA. (from Reynolds et al. 2002) 56 BIOLOGICAL SCIENCE REPORT USGSfBRD 2002-0001 descrted during predalion cvcnts. ~lultiplc kills ofcalvcs likely to increase from their present leyel of<250 animals were observed in C:lI\ada (Clarkson and Liepins 1993). in the ncar future. The increase in kills by grizzly bears suggests thai Ifexploration and extraction of petroleum resources prcdlllion may have bccn onc factor that resulted in vcry arc permitted in the Arctic Refuge coastal plain, low numbers ofcalvcs in late June of 2000 and 200J. associated industrial activities could further reduce the Deep snow and a prolonged winter seaSon in 2000 and number of muskoxen in the IDOl Area either through 2001 also likely contributed to the low numbers ofcalves induced disJlersal or decreased productivity and survival. seen in Ihose ycars and lllay havc cxacerbated the number /l.Iuskoxen arc year-round residents of the ID02 area, ofpredation events (Reynolds et a!. 2002). which heightens their vulnerability. In addition, their Shifts in distribution :lnd emigration also affected small numbers make it less likely that the Illuskoxen can numbers of muskoxen in the 1002 Area of the Arctic recover from perturbations. Refuge. Following their release in 1969 and 1970, most Status :llld distribution of muskoxen in and near the muskoxen became associated with 1 of 3 mixed-sex ID02 Area should continue to be monitored to document groups in 3 regions of the Arctic Refuge. The regions first future trends. occupied were located between the C3nning and Aichilik Rivers within the boundaries ofthe 1002 Area (Fig. 7.4a) Seasonal Strategies of Muskoxen: Distribution, (Reynolds 1998a). After 1986, muskoxen in mixed-sex Habitats, and Activity Patterns groups colonized new regions cast and west oftlle 1002 Area (Fig. 7.4c,d) (Reynolds 1998a). Seasonal shifts in distribution, habitat usc, 3nd activity In 1995, about 800 llluskoxen werc counted in the are means by which animals maximize energy intake and enlire range of the population (Table 7.1), which had avoid conditions that risk their survival. The muskox is :111 expanded westward to the Itkillik River, Alaska, and energetically conservative species (Klein 1992) and its eastward to the Dabbage River in northem Yukon seasonal habitat usc and energy budgets influence its Territory, Canada (Reynolds 1998a). In 1998-2001, reproduction and survival (While et al. 1989). Limited mixed-sex groups of muskoxen continued to expand their forage availability and energy constraints in winter as range west to the ColviJle River, southwest along the well as potential cumulative effects of disturbance Sagavanirktok River, and south and cast of the Babbage contribute to its susceptibility. River in northwestcrtl Canada. During these years, <700 As year~round rcsidents of the coastal plain of Ihe muskoxen were counted throughout the total range of the Arctic Refuge, muskoxen arc vulnerable to human population (Table 7.1) (P. E. RCyllolds, U.S. Fish and activitieS in both winter and SUlllmer. Information is Wildlife Service, unpublished data, E. A. Lenart, Alaska needed about their seasonal patterns of distribution and Dcpartment of Fish and Game, unpublished data, and D. activity to cvaluatc and minimize. potential effccts A. Cooley, Yukon Renewahle Resources, unpublished associated with oil and gas exploration and developmelll data). proposed for the Arctic Refuge's 1002 Area. Differences betwecn the observed and predicted Our study to detefllline seasonal patterns of lllusko;"en abundance in the 1002 Area, based on rc-collstmcted on the coastal plain of the Arctic Refuge had the population projections. suggest that ch:\llges in muskox following Objectives: I) comp:lfe distribution and habitat calf prodllction and animal survival caused most of the usc of muskoxen in different seasons, and 2) deteolline decline ill the rate of population growth (Reynolds 1999). seasonal movements and activity patterns of muskoxen. Density dependcnt factors as well as annual variability in rn the Arctic Refuge. snow is present from 8-9 months snowfall and increasing rates of predation atllikely e:lch year (September - 1\1ay). Fi\'c seasons werc delined influenced observed changes in calf production and for muskoxen based on ecological and hiological animal.wryival. conditions; call'illg (late l\farch to mid-June), summa Emigration of mixed-sex groups of muskoxen also (late June to mid-Septembcr), {'arfy winrl'r (late reduced the number of muskoxen in the 1002 Area Scptcmber 10 lllid-Nov~l1lber), mitt-wiTlfer (late November (ReynoldS 1998/1, 1999). In 2000 and 2001, the additional to mid-January), and 111ft' will/a (late January to mid emigration \)f mixed-sex groups containing marked I\farch). animals ;lJld the low rates of successful calf production To idemify pt1pulation distribution in different «5 calves per 100 females> 2 years old) contributed to .\caSOJlS, 19-25 radio-collared Illuskoxcn were monitored the declining trend in Ilumhers of muskoxen in the 1002 and 4 to 6 radio-relocation surveys were flown each year Area (P. E. Reynolds, U.S. Fish and Wildlife Scrvice, from 1932 to 1995. Locatil)lls of groups of muskoxen, unpublished data). both marked and \lnJ1lark~d, were determined using a Although muskoxen arc continuing to cKpalld into global positioning systcm or wer~ plotted on 1:63,360 their fonner range ill northem Alaska and nortllwestcO\ sL:;l!e maps. Canada, numhers of IllllskllXen inlhe ]()02 Area arc llOt ! ARCrIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SU~H..1ARIES 57 I b) 1982-85 Barter Island '\~Sagavanirktok R. c) 1986-89 ~ Canning R. Barter Island ---..c::r-"'-0-. ~ i:/-F.r J:&...... ""t...... , 11 .,'. !.i!!'~ ,'";.7 -y'~./'~ I•. :\.~Kongakut R. ~ r ~*_'~"" t',· ~\~\ ....~ ~~Il.:f :I~l.* 'F--'~ • t .::::.. ' ;.-:' ,l...·:· 'l"~c-a-n-a/d~a- \ ... . ., • ..•• 'I • • "ir. 1 \,- " • t-; -' .. ' ...... (" >'---~ )) d) 1990-93 rJ-;,r~-:~=""c~a;~;n:[ng R. Barter Island If//p,, ,C,),""1(1;;;'.... A"~ ,- .r'''''' "(. .~: (~.~ '~". ": t:- -:: '.. # Kongakut R. Il ... ' ..' ....<.~.; .' '~." .. -. : :.-: \:., ••_ ,~", •• :., • -, .... -" .. ' ...... f' ;, ...... ,. 1 '. '~'. £..-' ..:J"'~_~- ( • '.,. " : '. •••••••••• I ~ ",: ·'1 I'; : .I 'y~ .,~: ""----~t- ".,',':. Canada NAT10N~E:~~':E ~. r ('ARCTIC REFUG .. '~ CORE AREAS \~, 0 TOTAL RANGE + LOCATION OF MIXED·SEX GROUP Figure 7.4. Range expansion of muskoxen in mixed·sex groups in and near the Arctic National Wildlife Refuge. Alaska, 1969·1993. Total ranges were defmed by 95% adaptive kernel contours. Core areas were defined by 70% adaptive kernel contours. (from Reynolds 1998a) 58 BIOLOGICAL SCIENCE REPORT USGSIBRD 2002-0001 Table 7.1. Number of muskoxen seen in different regions in northeastern Alaska, USA, and northweslern Canada in 1982·2000 during pre calving surveys. GMU 268 and 26C are Slale of Alaska game management units. The muskox population originated from animals released adjaC€nt 10 the Arctic National Wildlife Refuge, Alaska. in 1969 and 1970. The muskoxen began to disperse inlo new regions east and west of the Arclic Refuge by 1986 (Reynolds 1998a). West altho Arctic 1002 Area in the Arctic East of the Arctic Refuge: Itkillik River to Refuge: All Arctic Refuge: Refugo in northern Arctic Aefuge Canning Rlyer (GMU canning RIver to Canning River to Canada Yukon Terrilory, + west + ensl Year 26B)0 Alchllik Aiverb (GMU 26C) Canadac 1982 219 219 2'9 ) 1986 9 386 399 23 431 1990 122 273 332 41 495 1995 330 228 321 146 797 1998 207 213 331 116 654 2000 277 189 246 149 672 a data source: E. A Lenart, Alaska Departmenl of Fish and Gamo, Fairbanks, Alaska, USA b regions first occuploo; numbers included in Arctic Reruga numbers \ c dlltll source: D. Cooley, Department of Renewable Rosources, Yukon Territories, Cannda Seasonal distribution and movemenl rates were core areas was highly variable in sumlller, out means determined from 15 female muskoxen filled with satcllitc differed by almost an ordcr of magnitude between collars (ultra-high frequency platform transmitter summer and other seasons. 111e minimum sii'.c of core teffilinals that were relocated by satellite) (Reynolds areas used in summer wa.~ >4 times larger than minimum 1989). Three to.'5 animals carrying satellitc collars were core areas occupied in winter or calving. monitored yearly from October 1986 through March rvtuskoxen wac conservative in their daily movements J992. These collars transmitted infonnation about animal throughout the ycar. Most (95%, Il = 2314) lllovelllelllS location and activity every second or thinl day for 6 hr/ made by satellitt-collared llluskoxen wtrc <5 km/day day (Reynolds 1998b). (Reynolds 1998b). Of these, 46<;·" were <1 kill/day. Seasonal distribution of the population and seasonal Moderate 1Il0V~ll1ents of 5-10 kill/day took pl3ce primarily home ranges of satellite-collared mu.skoxen \\"ere' between June and September (77 of lOS). Only 1 «1%) delineated with an adaptive-kerncltechnique and the moderate 1ll0\'ellle11l of 5-10 km/day was recorded program CALHOl\!E (Kie et :II. 1996). Seasonal between January and April. Movement rates >!O kill/day, differences in population distriblllion were cOlllpared as resulting in relatively long moves, w~re rare (18 of 2314); the overlap of core areas (70% cOlllour), distances 16 (89%) movements >10 km/day occurred in July. bet\\,'een core-area centers, and core-area sizes. Mean daily movemenls in summer (2.6 km/day) were Mean movement rates (km/day) for ench season and greater (P < 0.05) lhan in other seaSOllS (1.1-1.4 km/day) eaeh month were calculated from distanccs moved by {Reynolds 1998b). l\lcan rales of movcmenl were satellite-collared lllllskoxen. Distances were calculilted signific:Hllly higher (P < 0.05) in July than in olher between consecutive locations at 40-55 hr intervals. fo.1can months (Fig. 7.5). Activity counts/minute from satellite- activity indices for each season and each month were derived. AClivity counts from 5 satellite-collared 4 'AC~\Ilt)' Illuskoxen with >10 days of activity COUlltS pcr monlh " • ... mdex '.5 ~ were used to estimate mean aClivity (Reynolds 1998h). ~ 20 , 0 , ...... -.-I.'ovement rate ~ Lmd-cover and terrain lypes, extracted from a land c . . 'E ,,. . 2.5 15 , , ~ cover lllap derived from Landsat-Thematic l\lapper dala , . • ~ . 2 (Jorgenson et al. 1994), were Ilsed t\) determine seasonal • _0· --.:: ..... -.•..•.. • ~ 10 'J1\ ','0" • ~ differences in habitat usc at a landscape scale. Sekction , . '.'-...... ~---- 0 .. " B ralios of 6 laml·cover classes and 5 telTaln typcs wcre u , ./ ~ 05 based on prop()l1iol1s present in core :\reas (habitats Ibcd) o ~~.~~~-,-~-~ 0 divided by propo11ions in the entire study area (habitats !.lay Jul Scp Nov Jan Mar available) (Reynolds 199811). The average size \)f core areas IlsL'd by lIluskoxen Month carrying s:llellilc l:ollars was significmllly larger (Jl < Figure 7.5. Seasonal changes in rales of mo;'emenl and activity 0.05) in SUlllllll:r (223 km') than in calving season or lhe 3 counts of satellite·collared female muskoxen in and near lhe Arctic wintl:r seasons (27-70 kill') (Rcynolds ] ~)\)ob). Thc size of National Wildlife Refuge, Alaska, i986·1992. (from Reynolds 1998b) ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUMMARIES 59 collared muskoxen were also greater in summer (I' < and early winter bUi avoided in other se;lsons. Upland n.OOI) than in otln:r seasons. Activity COUnts differed shrub was selected only during the calving season and among months (I' = D.OOI) and were highest in July and avoided in other seasons. Bare cover (including bare lowest in April during the onset of the calving se;lson. ground, water, and ice) was .~eleeted in all seasolls except Seasonal home ranges occupied by females with spring. Mountain terrain was avoided in all se;lsons satellite-collars overlapped less (I' = 0.01) between (Reynolds 19981), calving and summer than betweell early winter and mid Ground-based studies (Wilson 19(2) provided more winter and betweell mid-winter and late wintCf (Reynolds information at regional and local scales (st'!' 11(':([ 1998b). This rdlccted Ihe sedentary nature and small subsectioll 011 wimer haln'fm /1.I't'). Locations of mixed-sex home range size of the muskoxen in winter. Distances groups of [lluskoxen during summcr and winter surveys between seasonal home ranges were also small. The demonstrated the importance of river corridors and distribution of the population of muskoxen occupying the adjacent uplands to this population (Fig. 7.6), coastal plain of the Arctic Refuge showed lillie change The small seasonal shifts in distribUlion and low between seasons. movemcnt ratcs observed in this study confinned that AI a landscape scale, muskoxen llsed rip;trian cover muskoxen arc energelically conscrvative throughout the along river corridors, floodplains. and foothills in all year (Jingfors 1980, Thing et al. 1987) and that they havc seasons. Moist sedge was selected in late winter and a high fidel it)' 10 geographic regions. Seasonal changes in calving; tussock tundra was avoided in late winter. Wet movcments. activity, and habitat usc were related to sedge was used in proportion to availability in summer 1002 Area Arctic National Wildllife Refuge Beaufort Sea Barter Islclnd r.~nniinn River Kongakut River 60 120 Kilometers ( , / / Jl 1\) ! ,/ Figure 7.6. Locations of mixed-sex groups of muskoxen seen during winter and summer sUf\leys in the Arctic National Wildlife Refuge, Alaska, USA,1982-1999. 60 BIOLOGICAL SCIENCE REPORT USGSfllRD 2002-0001 availability of forage and the energy budgets of weight arc less likely to breed or successfully reproduce muskoxen. (White et al. 1997) and arc less likely to survivc a severe In winter, snow limits forage availability and habitat winter. selection (1ingfors 1980). In late winter, muskoxen In our study we .found that movemcnl mtes :\lld selected feeding sitc.~ with soft shallow snow activity incrcased in June as plants began to leaf out and (Biddlccomb 1992, Wilson 1992). These siles were were highest in July as live plant biomass peaked (Chapin frequently narrow windblown bluffs adjacent to rivers 1983). Movcmcnt rates and activity of muskoxen carT}'ing where snow accumulation was low (Nclkmann ;lUt! satellite-collars began to declinc in August as plant Reynolds 1997), By mid- to late wintcr, riparian willows senescence and rut occurred (Reynolds 1998b). and wei-sedge cornllllillitics may be unavaihlblc to Seasonal strategies that emphasize energy inlake in muskoxen as snow depths increase (Wilson 1992, Evans sUlllmcr and encrgy conservation in winter, combined el 31. 1989). with physical adaptations for cold weather and the ability Winter forage of muskoxen is of low {juality (Staaland to process low quality forage, perrnitlTluskoxen to survive and Olesen 1992). Graminoids were a dominant year-round in locations seasonally avoided by most other component of the latc winter diet of muskoxen in animals. Muskoxen arc prcscnt during all scasons in the llortheastemAla.sb (O'Brien 1988, Biddlecomb 1992, potcntial oil exploration and development area of the Wilson 1992). l'vluskoxen, however, can digest low quality .·\rctic Rcfuge. grarninoids efficicntly and may havc a fasting metabolic This study did not quantify Ihe effects of pctroleum rate lower than other ruminants (Adamczewski et al. devclopment on muskoxen. But human activities that 1994, Lawler 200I). In winter, muskoxen conserve energy increase cncrgetic costs to muskoxcn in winter or by reducing movements and activity, decreasing the size decrease foraging opportunities in SUllllller have the of usc areas, and cOllcelllrating in 11 few habitats wherc greatest probability to affc.ct thc Illuskox population. foralle is not covered with deep snow. Riparian habitats frequently used by lIluskoxen arc also Unlike caribou that calve in early June when nutritious likely to be llsed as sites for gravel and water extraction vegetation is emerging, most muskoxen give birth several and wimer road construction if exploration and weeks before high quality green forage is available. In devclopment of petroleum resources occur on the coastal Alaska, Dall's slwcp (Ovis dal/i) (Rachlow and Bowyer plain of the Arctic Refugc. 1994) and moosc (Alces alet's) (Bowycr ct al. 1998) havc Exploratory and construction activities in northern similar calving strategies to muskoxen. To reproducc Alaska oftentJke placc in winter. Muskoxcn arc succcssfully, female llluskoxen must bc in good body parlicularly vulnerable to disturbance in winter because of condition at calving timc to fud thc high cos! of lactation. limited habitat, thc length of the arctic winter, and their TIleir cnergy-conscrving stratcgy of restricting necd to conservc cnergy throughout the winter including movcmcnts and aClivity and sclecting habitats w.ith low the calving season, The average size of muskox groups is snowcovcr allows female muskoxen to Ill:limain body larger in winter than in mid-summer (Reynolds 1993). condition throughout thc winter and spring (TIling et al. Large groups of animals often arc more easily disturbcd I 1987). than small groups be.cause largc gr0l1ps contain more l\.·lost llIllskoxcn in the Arctic Refuge givc birllJ in individuals respollsivc 10 pcrturbations. April and l\fay and Iactatc undcr conditions of poor Effects of human ,Ictivities on muskoxen are likely quality forage and harsh wcather. TIdr increased use of related to the scale of the activity and the availability of foothill terrain and upland shrub during the calving alternate habitats that can be Ilsed if animals arc SC<'lson reflected shifts into areas where snowcover was displaced. lv'Iuskoxen that expanded wcstward from thc shallow or blown free and thcir energetic costs of Arctic Rcfuge usc the widc Sagavanirktok Rivcr valley in fomging were lower. 11uskoxCll with young calves also summer despite the prescnce of the Daltoll Highway and Illay avoid flooded riparian areas during calving and post the trans-Alaska oil pipdine. Habitats availablc to calving periods. Iviovelllent rates of muskoxen carrying muskoxcn in the Arctic Refuge, however, arc satellite collars rcached a ycarly low in April at the onset geographically constricted: The coastal plain is narrower of the calving season. becausc the mountains of the Brooks Range arc closer to During thc sllow-free SllTlHner when food quality and the l3eilUfort Sea (Fig. 1.1). IJuantity arc high, muskoxen increase their movel\lcnt and If undisturbed, muskoxen generally slay in relatively activity, occupy larger areas, and usc di\'erse habitats as small areas lhroughout the wintcr. Avoidance by industry they forage 011 a variety of high-quality vegetation (Robus of these areas used by muskoxen could reduce the 1981, O'Brien 19S5). They tr;lck the changing plant probability of disturbance and displacemcnt of muskoxen. phenology in loc:ll arcas to obtain high quality forage and Minimizing human activities in areas occupied by rapidly regain body weight lost during winter. pregnallcy, llluskoxcn from mid-winter through the calving season and carly lactalioll. Musko,xcil that fail 10 regain body could reduce the likdihood of disturbance during the ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUl\fl\'IARIES 61 period when energy conservation is crjticalto survival. in feeding zones. Non-vegctative cover was greater in Locating permanent facilities away from river corridors, adjacent and nonadjacent wnes (Wilson 1992). Oood plains, and adjacent uplands could also help to Dict selection based on fecal analysis of winter pellets reduce potential effects of industrial development on (corrcctcd for digeslibility) indicated a high use of sedges Illuskoxen. (39.1%) and Illosses (24.6%) (Wilson 1992). Sedges and ,grasses were selected (use> availability); and horsetails, Winter Habitat Use by Muskoxen: Spatial Scales lichens, willows, and othcr sl1mbs were avoided (usc < of Resource Selection availability). Although selection for grasses was high, grasses did not make up a large proportion of the diet or During the snow season, which lasts up to 9 months in the available habitat. the Arctic Refuge, muskoxen remain in slllall areas, Analysis of mmen samples indicatcd that sedges restricted by the availability of forage and by strategies (31 %), grasscs (19%), mosses (15'."0), and forbs (13%) nccded to conservc energy (Reynolds 1998b). Human comprised most of Ihe diet. The proportion of willows disturbance or destmctioll of their habitat could displace was 8% in millen samples. In other studies, riparian Illuskoxen from these limited wintering areas. willows were used by muskoxen in latc winter (O'Bricn To detcrmine what kinds ofsites arc used by 1998, Robus 1991). During our study, howcver, snow llluskoxen in late-winter and why these sites arc selected, limited thc usc of Illost riparian shmb communities. we sct the following research objectives: I) detennine Willows Were browsed in areas where they protmdcd selection of vegetation types based on use and through the SIIOW (Wilson 1992). availability, and 2) compare .~now depth and hardness, Snow dcpth was shallower and softer in feeding zones vegetation biomass, and environmental variables at than in nonadjacent zones, and shallower in feeding zones feeding and non-feeding sites. Our study sites were th hardness were less in microsites than in unused portions reproduction. As winter progresses :lnd snow of feeding sites. Snow depth was the single variable most accumulates, or if deep snow falls early in the winter, influential in discriminating between used and non-used muskoxen lllay be forced to select foraging areas with areas. l\luskoxen also appeared to avoid walking through deep snow or low plant biomass. areas of soft deeJl snow. Most feeding zones were ncar If muskoxen arc limited in their accumulation of body some type of topographic relief that had been subjected 10 reserves during summer, effects of a severe winter or wind scarring. Snow depth was shallower in feeding overuse of winter range will have greater impacts on zones of tussock sedge tundra and moist sedge tundra, reproductive success and survival. If, in addition, animals suggesting that within vegetation types, muskoxen chose are disturbed by human activities and cannot optimally fceding zones based on snow depth alone. No differences use available habit lost while digging craters also reduccs the daily rate of 1)l1 a variety of high quality forage to regain botly \wight forage intake Crleischll1an 1988). before the nest winter. River c-olTidors and nearby In high snow years, when sOllie habitats are not uplands are often used by muskoxen in SUllllller. av'lilablc .llld llJuskoxen spend morc l'llergy moving .md Muskoxen in the Arctic Refuge arc vulnerable tIl foraging, muskoxen may be energetically constrained, disturbance frolll activities associated witll petroleuill resulting iJllow~r survival and Jess successful exploration and extraction because of their year-round ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SW...H..,.fAIUES 63 residency, their small population numbers and their need __' :lnd D. R. Klein. 1982. Productivity in recently to conserve energy for the 9 months of wimer if they arc eMablished muskox populations in Al:lska. Journal of to successfully reprodua. Wildlife Managclll<.'.nt 46: I092- 1096. Jorgenson, 1. C., P. 1:. Joria, T. R. McCabe, B. R. Reitz, M. K. Disturbances that displace lllusko.xen from preferred Raynolds, M. Emers, M. A. \Vrlms. 1994. Users guide for winter habitats into areas of deeper snow or that increase Ihe land·covcr map of the coaslal plain of the Arctic tlleir activity and 1l10venwnts could significantly increase National Wildlife Refuge. U.S. Fish and Wildlife Scrvice, their energetic costs in winter. Female muskoxen that arc Fairbanks, Alaska, USA. required to expend grealer energy to survive the winter Kie, J. G .. J. A. Balwin, and C. J. Evans. 1996. CAU-lOME: a wilt have fewer reserves for pregnancy and lactation and program for eSlimating animal home nmges. Wildlife lIlay not reproduce successfully. Muskoxen frequently use Society Bulletin 24:342-344. habitats along or adjacent to rivers. These locations llIay Klein, D. R. 1988. The eslablishmcnt of muskox populations by be sites for gravel and water extraction and winter road translOC:ltion. Pagcs 298-317 ill L. Nielsen and R. D. construction if petroleum development is permincd in the Brown, editors. Translocation of wild a.nimals. Wisconsin Humane Society, Inc., ~Iil\\'aukee. Wisconsin, USA. Arctic Refuge. __. 1992. Comparativc ecological and behavioral Avoidance by industry oflucas used by muskoxcn and adaptations of Ol'ibo$ l/10schalU$ and Rangijer tarandlls. the location of permanent facilities away from river Rangifer 12(2):47-55. corridors, flood pl,lins, and adjaccnt uplands could reduce L,l\vler, J. P. 2001. Ueat incremcnt and methane production by the probability ofdisturb:lIlce and displacement of illuskoxcn fed browse. Dissertation, University of Alaska, llluskoxen. Status :lIld distribution of muskoxen in and Fairbanks, Al:lska, USA. near the 1002 Area should be monitored 10 doculllcnt Nellemann, c.. and P. E. Reynolds. 1997. Predicting laIc winter future trends. distribution of muskoxen Ilsing an indcx of tcrrain ruggedness. Arctic and Alpinc Resean:h 29:33·1-338. 0'Bricn, C. Ii. 1988. Characteri7,ation of muskoJl habit.11 in References northeastern Alaska. 1l1csis, University of Alaska, rairbanks, Alaska, USA. Ad,llllclewski, J. Z., W. M. Kcrr, E. F. Lmllllcrding, and P. F. Olesen, C. R. 1993. Rapid population inere:loe in:m introduced Flood. 199·1. Digcstion of low pwtcin grass hay by llluskox population, West Greenland. Rangifer J3(1);27-3J. muskoxen and callie. JouJllal of Wildlife l\lanagclllcnt Raehlow, J. L., ,llld R. T. Bowycr. 1994. VariabililY in materna] 58:679-685. behavior of DalJ's sheep; environlllentaltracking or adaptive Biddlccomb, M. E. 1992. Comparati\'c p.1l(cms of wimer "trateg)'? Joumal of Mamm:llogy 75:328·337. habitat usc b)' lllllsko.,cn and caribou in norlhen! Alask:!. Rapota. V. V. 1984. Fceding ecology oflhe Taimyr lIlusko;l;en. lllesis, University of Alaska, Fairbanks, Alaska. USA. Pages 75-80 in D. It Klein, R. G. White, and S. Keller, Bowyer, R. T., V. Van Ilallenbcrghe, and J. G. Kic. 1998. Timing cditors. Proceedings of Ihe First Intcmatioll:ll Musko;l; and synchrony of parlUrition in AlaskallIllO()Se: long-term Symposiulll. Biological Papers, Uni\'Cfsity of Alaska S~cial vcnus proxim:11 c(fecls of climate. Journal of Manlillalogy Report 4. 79:1332-1344. Reynolds. P. E. 1989. An experimental satellile collar for Chapin. r. S. 1983. Direct and indircct cffects of t~mpern1Ure on nluskoxen. Canadian Joum:ll of Zoology 67: I 22-112-1. :lrctic pl'lIlls. Polar Jliology 2:47-52. _._.1993. 111e dyn:lInic$ of mtlsko;l; social groups in Clarkson, P. L"'md I. S. Lkpim. 1993. Gri7z1y hear. Ur.wJ northeastern Alaska. Rangifcr 13:83-89. ()rcIOJ, predation on muskox, ()~'ibl)s 1/l0.fC!latll.f, ~:\lves ncar __. 1998a. Dynamics and range expansion of:l rcestablished the Horton Rher, Northwest Territories. Canadian ridd Tlluskm popu!atioll. journal of Wildlife l\lanagement NalUralist 107: I00- I 02. 62:734-744. Evans, B. 1'.1., D. A Walker, C. S. Benson, E. A. Nordstrand. __. 1998b. Seasonal distribution, activity and h:lbitatuse of :\I1d G. W. Petcrsen. 1989. Spali;1l irllerrclatiom;hips betwccn nluskoxen in northcastcrn Alaska. Chaptcr 2 ill Ecology of a tcrrain, snow distribution :Hld vegetation pallcn!s at an arctic rcestahlj,hed populatioll of musko.'Cll in northeastcm foothills sile in Alask:!. Hol:lrctic Ecology 12: 270-278. Al:ISb. Dissertation. University of Alaska. Fairbanks, F.1ncy, S. G. 1986. Daily energy budgcts of caribou: a :\laska. USA. siJ11ulati()ll appro'lch. Disscrtalion. Uni\'ersity of AI:lska. 1999. Factors assm:ialeu with stabililalion of muskox Fairbanks, Alasb, USA. l1ulllbers ill northeastern Alaska. Paper presented at the Fki5chman. 5, J. 1988. A llwdcl of the cncrgy required hy TClllh Arctic lIl]gtllat,~ Conference. 9-12 August 1999. caribou to dig a fe<.'ding crater, Pag<.' 186 ill. R. D. Callinon. Tromso, N()[\,\'~lY. Suhmilled 10 Rangi fcr lin final rc\'i~i(ln). and J. L Davis. editors. Pro(,'c<.'dings \)f the Third North .__. 200I. Rcprodllcti\'c pallerns of f,'male llllbko.,cn in Allleric:11l Carihou Worbhop. !\Iaska Dcpartlllcill of Fish northeastern Alask:i. Alees 37(2): 1-8. and Game Wildlife Technicaillulletin S. _____, :111\1 H. V. Re)'nolds. 1999. Hody weight and Gllllll, A., C. Shank. and B. MtLcan. 1991. The history. Matus rC'pfllducdvc status of felllaic muskoxen in northeaSlcrll :lIld managemerll of muskoxcn on Bank.> Island. Arctic AlilSka. P:lper prcsented at thc Telllh Arctic Ungulate 44:1SS-195. Conference, 9-12 August 1999, Tromso, Norw~l)'. Suhmil1cd Jingfors, K. T 19110. Habitat relati'lrlships :lilt! activity paHerns to Rallgifcr (in fjnal rcvision). of a r"introduced I11lJsko)( P'>]lul:llion. 'J1lCsis, Universit)' of AlasJ.::l, F;lirhanks, AI:lska. USA. 64 BIOLOGICAL SCIENCE REPORT USGSfBRD 2002-0001 __, __, and R. Shideler. 2002. Predation and multiple kills of muskoxen by grizzly bears. UrsuS 13:in press. Robus, M. A. 1981. Muskox habitat and use palternS in northeastern Alaska. Thesis, University of Alaska, I~airbanks, Alaska, USA. Smith, T. IT. 1984, Population status and management of muskoxen on Nunivak Island, Alaska. Pages 52-56 ill D. R. Klein, R. G. White, and S, Keller, editors. Proceedings of the First Intcrnational Muskox Symposium. Biological Papers, University of Alaska Special Repon.1, Spencer, D. L., and C. J. Lensink. 1970.111C muskox of Nunivak Island. Journal of Wildlife Manage!llelll 34: 1-15. Slaaland, B., :md C. R. Olesen. 1992, Muskox and caribou adaplation to grazing Oil the AngujaarlOrfiup Nunaa range in West Greenland. Rangifcr 12:105-115. '111ing, fl., D. R. Klein, K. Jingfors, and S. Holt. 1987. Ecology of muskoxen in Jameson Land, northeast Grl'cn land. Holarctit.: Ecolog)l10:95-103. White, R. 0., D. E Holleman, and B. Tiplady. 1989. Se;lsollal body Weight, body condition, and lactationaltrcnds in muskoxen. Canadian Journal of Zoology 67: 1125-1133. __, J. E. Rowell, and W. E. Hauer. 1997.TI1C role of nutrition, badycollditian nod bctalioo on calving success in muskoxen. Journal of Zoology London 243: 13-20. Wihon, K. J. 1992. Spalial scales of Illusko;r; resource selection in latc winter. TIlesis, Univer:;ily of Alask;l, Fairbanks, Al.1ska, USA, SU~HvfARIES ARCflC REFUGE COASTAL PLAIN TERRESTRIAL WILDLiFE RESEARCH 65 Section 8: Polar Bears movemcnts of females with cubs were lower than single females. SrCW'!l C. Amsrrup Total annual mOVemcnts ranged from 1,454-6,203 km. Bcars lhat spcnt part of the ycar in dens moved less Ihan Movements and Population Dynamics of Polar others, but non-denning classes of bcars did nOl differ in Bears t0l:11 annualmovelllent (AmstnJp 1995, Amstrup et al. 2000). Polar bears (Ursus !I1aritimus) arc hUflled througholU Fcmales with cubs were generally lhe mOSI active most of their range. In addition to hunting, polar bears of group, ,lilt! single females the least active. Highest and the Beaufort Sea region arc exposed to mineral and lowest levels of ,lctivity were recorded in June and petroleum extraction and rdated hUlllan activities such as Scptember, but there also was a strong activity peak in shipping, road-building, and seismic testing (Stirling early winter. Activity levels were lowesl in the early 1990). morning and higher from mid-day through late evening. Little was known at the start of this project about how Beaufort Sea plllar bears kept their tIl0Velllelll.~ within polar bears move about in their environment; and boundaries outside of which they seldom ventured. although it was understood that many bears travel across Annual activity areas ranged from 12,730 km~ to 596,800 1 political borders, the boundaries of populations had not km • tlfonthly activity are:lS ranged from a mean of 344 been delineated (Alilstrup 1986, Amstrup et al. 1986, klll~ for females with cubs in April to 11,926 klll~ for Amstrup and DeMaster 1988, Gamer et al. 1994, Amstnlp females with yearlings in December (All1Slmp 1995, 1995. Amstrup et al. 1995, Amstrup 2000). Amstmp et aJ. 2000). As human populations increase and demands for polar Bears from the Beaufort Sea population occupied all bears and other :lrctic resources escalate, managers must area extending up to 300 km offshore, from Cape know the sizes and distributions of the polar bear Bathurst in Canada to PI. Hope, Alaska, and enclosing populations. Resource managers also need reliable 939,153 klll 1 (Amstrup et aJ. 1986, Garner et al. 1994, estimates of breeding rates, reproductive intervals, liller Amstmp 2(00). .~izes, and survival of young :llld adults. Animals origin,tlly captured along the Beaufort Sea Our objectives for this research were I) to de!emline coast spent appro.>;illlately 25% ofthcir lime ill the the seasonal and annual movements of polar b~ilrs in the llortllcastern Chukchi Se:l, but animals captured in lhe Beaufort Sea, 2) to define the houndaries of the Chukchi Sea vcntured into the Beaufort Sca only 6% of population(s) ll.~ing this region, 3) tQ detennine the size the time. With few exceptions (Dumer and Amstmp 1995) and status of the Beaufort Sea polar bear populatloll, and bears captured in the Beaufort Sea were faithful to 4) to establish reproduction and survival ratcs (Amstmp Sllllllller activily areas in the central portion of the 2000). Beaufort Sea (Amslmp et 31. 1986, Amstmpl995, One-hundred-fifty_tllrcc satellile radio collars (P1Ts), Amstmp et al. 1995, Amstrup et al. 2000). Although any fillcd to 106 adult female polar bears in the Beaufort Sea, bear caught in this region could be relocaled anywhere were relocated 37,277til1les between 19R5 and 1993 else in the region, individual bears appeared faithful to (Arnstrup 1995, Amstrup 2000, Amstmp ct at. 2000). gencral geographic regions (Fig. 8.1). Rccelll analyses of Polar bears were observed to move more than 4 km/hr for pallerns in scasonal fidelity of polar bears (Bethke et al. extcnded periods, but mean hourly rates of movement 1996) suggested tllat 3 scparate populations or stocks varied from 0.30-0.96 kill/hr. Females Wilh cubs had could be distinguished. lower hourly rates of movement than females with Thesc 3 relatively discrete stocks overlap to a grcater yearlings and those (single females) without YOllng. or lesser extent within Alaska waters (S. C. Am.~trup, U.S. ~'fovellient rates varied si~nificall!ly among months: Geological Survey, unpublished data). Thercfore, it is no thcy ~enerally were lowcst in sprin~ and late summer and longer re'l.~onable to refer to only I group of polar bears highest in early winter (Amslmp 1995, Amstrup et al. (Amstrup 1995, Amstrnp 2000) occupying this region 2000). Geographic displacemcnls frolllthe beginning to (All1stmp et al. 2001). AltllOugh these groups arc not the cnd of each month were slllaller for females with cuhs distinguishable genetically (Paetkau cl al. 1999), thev arc of thc year than for single females, and larger ill distinct enough to mandalc managllment rccogniti()J1~ Novcmber than in April. Two groups, the Chukchi Sea and the Southern Tn I\by, JUlie, July, and August, radio-colbred bears Beaufort Sea populations, sharl~ the mainl;md CO;lSt,11 .~hifted locations to the north. Collared bears moved hack areas of Alaska in the grllatest numbers (Amstrup ct al. to the south in October. Mean tOlal distances moved c:lch 2lX)l). Recognilion of these stocks helps to explain some Illonth ranged from 186-492 kill. Total movcments in of tlw lllo\"emem p / ./ \ \ / / Chukchi ./ n = 4977 / (125) / \ ID®iii1 ..90 r-T~l~ ,;/ ~g := =P~T~ / ~g --r~- ;~g -'~E- 3040 ,-~~~==, / 3540 18 ~"=-=- / ~g o I/ 20 167D I Figure 8.1. Numbers and relocation positions of satellite radio-collared polar bears (# of individuals) captured in each of 6 longitudinal zones within the Beaufort Sea. Histograms illustrate proportions of those relocations made in each zone. For example, 32% of the 2,226 relocations 01 bears originally captured in the Lonely zone were recorded in the Barter Island zone, Alaska; 47% of the 1,079 relocations of bears captured in the Wainl'.Tight zone, Alaska. were recorded in the Chukchi zone. OCCurs in Alaska and much of the harvest along the lIew ability 10 estimate potential impacts that oil spills mrlinland coast of northwestern Canada. may have on polar bears. TIlnt ability has major Oat;l were analyzed for .189 captures of 534 bears ral1lificatiol1.~ for assessing risks of a variety of potential between 1967-1974 (a period of hypothesized over developments (Dumer et al. 200lb). harvest) and for 1.087 captures of789 bears obtained Both IOllg and short-term trends in condition of octwcen 1981-1992 (:1 period when the population should individual animals were observed during this study. have recovered from over-ha!"vest). Population growth Condition of adult females, as reOected by total mass. throughout the intervening years was also examined showed significant seasonal trends (Durner and AmstrIJp (Am5tmp 1995, Al11.~trup ct al. 200 I). 1996). Despite seasonal Ouctuations, longer-term trends Amstnlp et al. CWOI) and t1cDonald and Amstrup also were suggested. Trends in recruitment and survival (2001) suggested that the Humber of polar bears in the rates (in the 1970s compared with those from 1980 Southern Bcaufort Sea popuilltion grew at more than )';';;, through 1992) suggested all inverse compensatory per year between 1967 and 1998. reaching an estimated relationship hetween tlllal popUlation size and recruitment population tll'lt could he as high as 2.500 animals. of sllbadults. Popul:llion size alone explained ,SSt;:;, of the Although contact with hydnw;lrbons Gin have scriOlIS v.1riation in pmportions of 2- anti 3-year-olds in annual ramifications for polar bears (Amstmp et al. 1(89). the samples (Armtrup 1995). Large populatiolls of the laller Jlolar bear's apparent rapid population growth has pan of the slUdy appeared to recruit proportionately fewer spanned the entiro.~ history of petroleum de\'l'lopmcllt in ju\'cniles, and snwller popUlations of the early pari of the arctic Al:lskil fAmstrup 2000, Amstmp et a1. 2001. study recntitetl higher proportiolls of juveniles. i\lcDonald and Amstrup :WO\). This suggests that Condition of single adult females and those willi cubs, managed resource development can be compatible with ;15 rctkctcd in mcasuremcnts of ;lxi;ll girth. appeared to healthy polar bear popUlations. Also ellcouraging h [he decline significantly :IS the population grew. PI)jlulatio/J ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDUFE RESEARCH SUMt-.'fARIES 67 size alone explained 75% of the variation in axial girth of now be ncar historic highs, managers must be alert to reproductive age females. possible changes in human activities, including hunting Although numbers of young produced per female and habitat alterations that could precipitate future when the population was small «0.40) and when it was declines. large «0.38) were similar, Iillers of Illore than one yearling were more frequell! when the population \Va.'i Reproductive Significance of Maternity Denning small. Sampling inconsistencies during the 2 periods on Land precluded comparison across years for cubs and 2-year olds but not for yearlings. Observed reproductive The distribution of polar bears is circumpolar in the intervals of 3.4 and 3.7 years in early and late periods N{)fthern Hemisphere, bUlmatemal dens known at the were suggcstive of change, but not significantly different stan of this project were concentrated in relatively few, (Amstrup 1995). The :lge structure of the small population widely scattered locations (Amstnlp 1986, Amstnlp et al. \\'a,'i younger than that of the larger population of later 1986, Amstnlp and DdI'laster 1988, Amstrup and Gardner years. 1994). Survival of aduHs, as calculated from life tables, was Among the best-known denning concentration areas higher :lIId survival of yOLlng lower when the population were the SVillbard Archipelago north of Norway; Franz was large. Survival rates of adult Beaufort Sea polar Josef Land, Novaya Zemlya, and Wrangel Island in bears, however, were as high or higher than those Russia; and the west coast of Hudson Bay in Canada. measured anywhere else. Annual survival of radio Denning W;JS cither unCOllllllon or unknown in gaps collared females ranged from 0.946-0.980 (Amstrup and between known denning concentration areas. The Dumer 1995). Survival of cubs ranged between 0.610 and Beaufort Sea region of Alaska and Canada lay int11c 0.675, while that of yearlings was 0.751-0.903. large.~t of those gaps, :md some had hypothesized that Intllis study hunting explained 85% of the polar bears of this region actually were born in other documented deaths of adult female polar bears (Amstrup areas. and DUnJer 1995). Natural mortalities were not cOllllllonly Now we realize that the coastal plain area of the Arctic observed among prime age animals (Amstrup and Nielscn National Wildlife Refuge lies in a region of polar bear 1989), and we still know lillie about Ille proxirn:lIc causes denning; :ll1d its coastal plain also may contain significant of natura} deaths among polar bears. gas and oil resources. Polar bears in dens could be In the early 1990;;, the trends described above affccted in many ways by petroleum development, but suggested a population that could be approaching carrying neither the distribution of dens nor the sensitivity of bears cap;lcity and was dtller swble or growing more slowly in dens was known before our rcsearch (Al11stnJp 1986, than in the early 1980s. 1I.10re recent data suggest an Amstrup and DeMaster 1988). alternate hypothesis: ApP;lrent density dependence was a To ;lscerlain the /lumber and distribution ofJenning function of more transitory ccological effects. The polar bears that could be impacted hy oil development on apparent continued growth of the population illlo the latc the Arctic Refugc coastal plain, we cstablished the 19905 and the expansion of numbers of matcrnal dens as following research objectives: I) to determine the well as expanded ureas ll.~ed for Jenning (st'(.' bdo\l') distribution of polar bear dens in northem AlaSKa, 2) to appear to contradict earlier conclusions regarding as<2ertain the time that polar bears enler and emerge frolll carrying capacity and density effects. This suggests that dens, 3) to calculate the relative success rates ofdens or] issues related to population statuS should be revisited land and 1)J1 sea icc, and 4) to determine whether oil and (AllIstrup et a!. 1986, Arnstrup 1995, Am.,tmp et a!. 2001, gas exploration and dcveloplllelll ofthe Arctic Refuge tl-fcDonald and Alllstrup 2001). coastal plain would adversely impact polar bears of the Estill1:lIed numbers of bears at the close Ilf tile study Beaufort Sea by dismptillg denning activities. were relatively large. Effects of the increasing human Po!;lr bears were captured and radio-collared between intrusions into the polar be;lr environr1lent lI;we not been 1981 and 1992. Amstmp and Gardner (1994) determined observed at a population level, suggesting that pro;H.:tive that denning in the Beaufort Sea region was sufficient to management can assure coexistence of polar bears ;lIld account for the estil11;lIed pOJlulation. They :llso noted that human developlllents. the proportion ofdens on land was. higher in the !nte AbsllllllC numbers of bears, howcvCl", still are ,mall I980s and early 1l)()Os than it was earlier in the study <2ompared to many other .~pecies. Early estimates (Fig. S.2). 'nl;lt trend continucs, and other distributional suggested the additional loss of ;IS fev,; ·as 30 bears each changes al so Illay have occurred in the late 1990s and year might push the total take from the population to the early 2000s. Of a IOtal of IS2 dens located by telemetry m;lxillluill sustained yield (Amstrup et al 1986, Amstfup between ,~pring of 1982 and spring of 2001, 150 were ;md DeI\'faster 1988). Excess take did predpitate a decline within the study area from 16]0 to 137" W longitude in the 1%05 Hlld 1970s. H,:nce. although POPlJlatillJlS may (Pointl-Jope to :'hJc.kenzie Rivcr). Polar bear dens in this 68 BIOLOGICAL SClENCE REPORT USGSfBRD 2002-0001 14 WCre II November and 5 April for land dellS and 22 November and 26 lvtarch for pack-icc dens (Amstnlp and ~ 12 DFASTlCE a LAND Gardner 1994). ~ 10 ~ aPACKICE Female polar bears captured in the Bl:aufort Sca ~ apPl:ared to be isolated from those caught cast ofCape •.r; e6 Bathurst in Canada. Bears followed to >1 den did nOI , reUSl: siles, and consecutive dens were from 20 km to 8 4 ~ 1,304 kill ap region continued !O occur on land, pack iL:e, and land-fast The proponion ofdens locatl:d on the Arctic Refuge ice. dropped frolll 47'70 10 41 % when lhe periods before :lnd Seventy-three of the 150 mateOlal dens discovered by after 1992 wcre compared, while the proponioll of dens telemetry between 16r Wand 137" W wefl~ on land or located within the bounds of the 1002 area dropped from land-fast ice where they wcre potcntially vulnerable to a 36% 10 30%. The decrea.'>c in proportion of land dl:llS on variety of human disturbances. the Arctic Refuge was accomp3nied by an increase in the The remaining 77 identified maternal dens were on proportion of dellS found 011 land areas west of the Arctic drifting pack ice where they were relatively invulnerable Refuge. Although this diSlribution shift is 1I0t statistically to most hUlllan 3ctivities. 111e proportion of pack-icc dens significant (Chi-square lest P = 0.88), it is readily dropped dramalically in the lauer half of lhe study. A app.:m:nt all the m.lp (Fig. 8.4), decrease in slUdy elfort in offshore regions in the late The shift may be explained simply by sample size 1990s lIlay explain a portion of thc declinc inl\umbers of limitalions. The continuing growth in polar bear numbers, dens found on p:lck ice. Bears denning on p ---1 . -,--- j I \ ------i --I- \- / \ ! ------1_, ,-- Figure B.3. Maternal den locations for 5polar bears followed to dens for more than one ~ear. All dens were located by radio telemetry. Bears repeatedly denned inlhe same general geogmphic area, but not the same place. Likev,ise, polar bears repeatedly denned in the same substrate. (from Amstrup and Gardner 199.t) ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUt-.·ft-.1ARIES 69 170' 165' ,.,. ISS' ,,,. 145' 140' 135' ,,,. , , :- , • ~ , , , ., , ~" , (', , , • , , ' ,, $:. ,-'<\. ., .• ~ ., , ,. \~ f/ ,!< ,', \ <8. ., " i:-' .. ~ '" « '%, 0 .f,.. (,1 ,;" ,. ,. '1,·1] ," throughout the sludy period. 111e distribution of lIlatemal (Amstmp 1993). Pcnurhatiolls resulting from capture, denning continues to be a fenile area for future research. marking, and radio tracking nwtcmal bears did not affect Despite a possible decline in proponionaluse of the litter sizes or stature ofeubs produced; and 10 of 12 Arctic Refuge for denning, there still appears 10 be a denned polar bcars exposed to exceptional levels of higher concentration of dens on the Arctic Refuge than on activity were not measurably affccted (Amstmp 1993). adjacent lands. DeveloplJlcnt of hydrocarbon resources Hcnce, polar bears in dens llIay be less vulnerable to tllerdorc could incrC'\.~e the potential for disturbance of human disturb,lnces than previously thought. TIlis finding denning polar bears by human activities. corroborates the oh.~crvadons or Blix and Lentfer (1992) Because the chronology of denning is now known, who reported that polar bears in dellS arc well insulated howcver. human activities could bc temporally managed from disruptions outside of their dellS. to minimize cxposure of denning bears (AmstOlp 1993, Aggressive and proactive management, therefore, can Amstmp and Gardner 1994). Spatialmanagelllcnt of minimize or e1iminatc most of the potential adverse industrial activities could further Illinimize exposure of clfeets of hUlllan developmcnts on denning polar bears. It dens to disturbanc~s because Jenning occurs in low will be important to conduct rcsearch and monitoring of density (including the Arctic Refuge) within relatively polar bear denning and ecology concurrent wilh any uncomlllon habitats that can be mapped (Amstmp 1993, approved dcvelopments III assure that managelllent efforts Dumer el al. 200Ia). do have the desired mitigation effccl.~. Available data indicate polar bears arc relatively resilient to disturbance, coming from Ollt side their dens (Amstrup 1993. Amstrup ,lIld Gardner 1994). Data showcd that dcns exposed to even high levels of activity did nol suffer a delC'cwble reduction in productivity 70 BIOLOGICAL SCIENCE REPORT USGS/BRO 2002-0001 References __• _~, and T. L. McDonald. 200lb. Estimating the impacts of oil spills on polar bears. Arctic Research of the Amstrup, S. C. 1986. Pobr bcar. Pages 790-80~ ill R. United States 14:33·37. DiSilvestro, edilOr. Audubon wildlife report, 1986. TIte Gamer, G. w., S. C. Amstrup, I. Stirling, and S. E. Belikov. National Audubon Society, New York, New York, USA. 1994. Habit:ll considerations for polar bears in the North __. 1993. Human disturbances of dcnning polar be;lrs in Pacific Rim. Transactions of lhe North American Wildlife Alaska. Arctic 46(3):246-250. and Nalllral Resources Confcrence 59: 111-120. __. 1995. Movcmcnts, distribution, and population McDonald, T. 1.., and AmstnJp, S. C. 2001. Estimation of dynamics of polar bears in the Bcaufort Sea. Dissertation, population size using opcn capture-recapture models. Unj;'ersity of Alaska, Fairbanks, Alaska, USA. Journal of Agricultural, Biological, and Environmcmal __.2000. Polnr benr. Pages 133-157 in J. J. Truen and S. R. Statistics 6(2):206·220. Johnson, editors. TIle natural hislOry of an af<;tic oi] field: Pactkau, D., S. C. AmstOlp, E. W. Born, W. Calvert, A. E. development and biota. Academic Press, Inc., New York, Derocher, G. W. Garner, F. Messier, I. Stirling, M. Taylor, O. New York, USA. Wiig, and C. Strobeck. 1999. Genctic structure of the __, and D. P. DcMastcr. 1988. Pobr bear Ur.ws marilimlls. world's polar bear populations. 1..lotccular Ecology 8: 1571 Pages 39-56 in J. W. Lentfcr, editor. Selected llw.rine 15S.:I. mammals of Alaska: species accounts with research and Stirling, I. 1990. Polar be;lrs and oil: ecologic perspectivcs. manngemcnt recommendations. "tarinc Mammal Pages 223-234 ill J. R. Geraci and D. J. SI. Aubin, editors. Commission, Washington DC, USA. Sea Mamn1:lls and oil: confronting the risks. Academic __, and G. M. Dumer. 1995. Survival of radio-collared polar Press, San Diego, California. USA. bears and their dependent young. Canadian Joumal of Zoology 73(7): 1312-1322. __, and __, 1. Stirling, N. J. Lunn, and F. Messier. 2000. Movements and distribution of polar bears in the Beaufort Sea. Canadian Joum Section 9: Snow Geese g • 30 Jerry n~ lillpp, OOlllla G. Robnt.'lo/l, am! A/all IV. ~ Brackney 200 '"•0 Size and Distribution of Snow Goose " 0 Populations -" 100 ~• ,E Part of the coastal plain of the Arctic National Wildlife z 0 Refuge, Alaska, is used as all autumn staging area by 82 83 84 85 86 87 88 89 92 93 lesser snow geese (Chell cacru{c.fcens c(/nllh'.fc~'!ls) from Year the Western Can;:ldian Arctic population (hereafter called the Westem Arctic population). There were approximately Figure 9.1. Numbers of lesser snow geese observed on the coastal 200,000 breeding adults in the Western Arctic population plain of the Arctic National \'fIldlife Refuge, Alaska, USA. during aerial through the mid-1980s (Johnson ~llId Herter 1989), btlt the surveys from 1982·1993. Poor weather prevented surveys in 1990 and population has recently increased to about 500,000 1991. breeding adults (Kerbes et a!. 1999). Early in their autulllllllligration, adult and juvenile features snow gtese selecled when feeding (Hupp and snow geese from the Western Arctic population feed Robertson 1998). intensively while staging on the Beaufort Sea coastal plain in Canada and Alaska to build fat reserves lJ(;:eded Snow Goose Habitat, Food, and Energy for migr~ltioJl. Aerial census!!.s from 1973 to 1985 Requirements indicated that up to 600,000 adult and juvenile snow geese used the coastal plain for 2-4 weeks in late August TIle staging ;:Irea on the Beaufort Sea coastal plain until mid-September (Oates et al. 1987). provides forage tll .. t geese use to build energy reserves We studied arlnual variation in numbers and sp;lti,ll prior to continuing their migration sOlllh (Pallerson 1974). distribution of snow geese tlwt staged on the coastal plain Upon departure from the cO;lstal plain, snow geese make a of the Arctic Refu£e. 2,000-klll-nonswp night to tlle next stopover area in Numbers and distribution of SIIOW £eese on the Arctic 110nhern Alberta (Johnson and I-lcner 1989). Geese that Refuge were assessed from aerial surveys during 9 years lack sufficient fat reserves lllay be less likely to survive from 1982-1993 (Robertson ct al. 1997). During surveys migration (Dwell and Black 1991). biologists estimated the numbers ofgeese in flocks and Because snow geese arc easily disturbed by human marked flock locations olllOpographic maps. Survey aClivity (Davis and Wiseley 1974, Wiseley 1974, Belanger results were digitized on a lllilJl of the coast:d plain. A grid and Bedard 1989), development of the coastal plain could of 25-km" cells was superimposed over the digitized map. displace geese frolll feeding habitats. Exclusion from We t~llJied the numbers of geese observed in a cell during feeding habit:lts could reduce the likelihood that staging each survey and the /lumber of years each cell W~lS uscd geese would acquire fat reserves needed for migration. To by geese. identify snow goose areas that could be impacted by The numbers ofsnow geese that staged on the Arctic developmellt, we needed data on forage preference as Refuge ranged frolll 12,800 to 309,200 individuals across well as the distribution and avaihlbility of feeding years (Fig. 9.1). The numbers were highly variable habitaL~. because in some years most of the population remained in We studied body condition and diet of snow geese in Canada. whereas in other years the majority of the order 10 understand their energetic and nutritional Westem Arctic population staged on the .·\rctic Refuge. demands. Wc also ~lssessed usc and availability of fceding Snow geese occupied approximately 605,000 ha of the habitats and the effects that grazing geese h;ld on Arctic Refuge coastal plain between the I-Iulahula River vcgetation at the.~e sites. l and Canadian horder. Only 20',:;" of the 25-klll t:ells wcre Body condition and diet tlf l.'i I snow gcc~e collct:ted frequently u.~ed (i.e., used ~j years) yet 80% of the durin!:! 1984-85 ;UH119K8 were cvalll;lted (Fig. 9.3). Adult frequently 1I,eu cclb fell within the boulldarie.~ of the sl\ow-gecsc gained an average of 22 g of body f;lt/day and JO02 Area (Fig. 9.2). The mid·coastal p!;lin,!letween thc departed the Arctic Refuge with about 600 g of fal Okpilak and Aichilik rivers was used more frequently reserves. Juveniles ;lrrived on the Art:tic Refuge with than areas ncar the coast or the steep foothills. ArC;lS that srna!lt:r fat reserves than adults, acquired lipid reserves at were used frequently were :l!sO llsed by larger Illllllbers of a slo\\"er rate (I] g/day), and departed with smaller geese. Frequently used ;lreas had Illore of the landscape reserves (375 g). At the end of staging, juvcniles lj;\d 72 BIOLOGICAL SCIENCE REPORT USGSffiRD 2002-0001 A N -_.:::::", ------=-- _ High Use,AreI1 (5 or more }'\'anI) _ Medium Use Area (3 to -I years) Lesser Snow Geese _ Low Usc Area (1 to 2 yell1!:i) Use Areas, 1982 - 1993 r:::J An.1.k NWR l..and.5 o S 10 15 20m! rZJ Kaktovik Jnuplat Corp. u.nds -- 1002 Boundary IJ 8 J6 U ~km FIgure 9.2. Frequency 01 use of 25·km 1 cells by lesser snow goose flocks on the coastal plain of thQ Arctic National 'Nildlife Rduge, Alaska, 1982-1993. Use of ceils by snow geese was assessed during aerial SUlveys. proportionally smaller lipid resen'es (15-18% of body population of 300,000 snow geese that stages for 3 weeks Illass) lhan adults (21-24':',;" of body mass) and likely were could consuillc as much as 4,200,000 kg (wet mass) of al greater ri.~k of having inadequate energy reservcs for cO!longrass stembases. Thus the population consumes a migration. very large amount of forage in a short period. We examined esophageal contenls of snow geese to Nonhem scouring-rush primarily grew on riparian idelltify important forage species (Brackney and Bupp terraces within 400 m of river channels. Riparian terraces 1993). Snow geese primarily consumed 2 food items: the adjacent to rivers arc important habitat for snow geese as underground stcmbase of Eriophorllm IJIlgusrijolillll1 (tall Illey feed on scouring-msh. couongrass) and the aerial shoots of Eqllist'1U1II We measured vegetation and soil moisture at sites variCglll!l1Il (northern scouring-rush). The birds typically where snow geese fed 1m lall cOllongrass, and then we fed on northern scouring-nlsh during the morning whell devdoped a statisticall1lodelto identify suitable feeding surface soils and Wall:[ were frozen, and they consumed habitat (llujlp and Robertson 1998). Thc model was tested underground parts of tall coUongrass during afternoon using captive snow geese. Snow geese typically e.\ploited and evening ancr soils had thawed. small, homogeneous patches of cOlltlngrass in flooded We examined forage illlake and digestibility among areas. 'Illey avoided uplands and flooded areas where captive snow geese 10 beller understantlthe population's cOllongrass was imermixed with Cafex, shrubs, or forage requirements (Hupp et a!. 19(6). Snow geese fed tussocks. for a high percentage of the day (5{)'(iO';""r) and maintained The habit'll selection model was used to assess the high rates nfforage intake (14 g dry matter/hour). On a availability of couongrass feeding sites along 192 daily hasis a goose probably consumes the equivalellt of randomly located transects on the 1002 Area cast of the about 3Wi, of its body llIass in clltlOllgrass stl'lllbases, :\ lIulahula River. Cottongrass fceding sites occurred in ARCTIC REFUGE COASTAL PLAIN TERRESTRIAL WILDLIFE RESEARCH SUl....IMARIES 73 ADU.TS reduces forage availability in subsequcnt years. Geese ." may be unable to successfully exploit a site for several years after it has been grazed. §6Xl Snow geese consume large volumes of forage at • feeding sites that are slll ." JlNENILES Effect and Mitigation of Human Activities on :§ Snow Geese ." III Staging snow geese are easily disturbed by aircraft 0: y = 101.5 +13.1x • :J •'" •• activity (Davis and Wiseley 1974, Belanger and Bedard "'" 1989). Repeated aircraft disturbance can reduce their rate 0 of food intake due to disruption of feeding behavior and displacement from feeding habitats. Reduced fat "" accumulation and diminished survival during migr3tion could result from repeated aircraft disturbance. o 5 10 15 20 25 The following objectives were designed to llssess DAY OF STAGING snow goose response to experimental aircraft overflights: I) determine the effect of aircraft on activity patterns and FIgure 9.3. Rates 01 lipid deposition by lesser snow geese during fall habitat usc, 2) calculate the effect of increased stress or staging on the Arctic National Wildlife Refuge, Alaska. Geese were displacement caused by aircraft overflights on the energy collected in 1984, 1985, and 1988. Data were pooled across years and budgels of the geese, and 3) determine implications of size of fat reserves scaled to the date geese were first obselVed on the petroleum devcl(lpmelll to survival of snow geese. Arctic Refuge in each year, Studies ofaircraft disturbance were limited due to low snHlll patches that were highly interspersed with less numbers of geese on the Arctic Refuge in most ycars from 1988-1993. poor weather, and the need to meet other suitable feeding habitat. 'Il\l~Y were widely distributed but comprised a small percentage (.:53'}i;,) of the study area. study objectives. Snow geese flushed at a mean disl;lnce of 5.2 km (SD = 2.Y) from a Bell 206B helicopter during Larger-scale micro-relief features weft~ also examined overl1ights in 1991 (11= 19). Flocks were displaced an at SIlOW goose fceding areas. COHongrass feeding sites average of 1.8 km (SD = 2.0) froilltheir feeding sites. primarily occurred along Ilarrow « I 1lI) edges of Hooded thermokarst pits, water tracks, and troughs. When feeding TIlese results arc similar to a 1973 study of aircraft distmhance to the Western Arctic population in Canada in on cottongrass, snow geesc selected area.~ with greater which fixed-wing aircraft and helicopters l1ushed snow availability of therlllok2 disturbances! hom caused fewer geese to usc the disturbed area cotlongrass frolll which plants rcgenerate. Four years after 50% !11e following day (BClanger and Bedard lYH9). Energetic an expaimemal removal, the biolll Public rtportlng burden for ifill colltetlon JI nUmaltd to Ivtrlll11 hour ptr ,"pon.., Including time for reviewlrJil imlructlons, searching e.dstlnll data sources, g~ and malnlalnllv the data oeeded. and COOlple~r"9 and revlewlng the collection of Informallon. ~nd comments regardinll this burden e1linate or any othet aspect of this Mecllon of 1nl00000lon,lnduding Sl1J9llSllom fOf rllducing this boo:!en, to Washlr9lon Headquartm Ser..lces, Directorate for Inlormatlon Operations and Reporb, 1215 Jefferson Davis Hl;lhway, Suile 1204, Allington. VA 22202""'302. and to lhe OfrK:e of Managemenl and Budge!, PapefWOl1( RedvcUon Projoc:t j0704..()168) WaslllrYJlon. DC 20503. 1. AGENCY USE ONLY (laM BIn) 2. REPORT OATE 3. REPORT TYPE AND OATES COVERED April 2002 Biological Science Report 4. TITLE AHD SUBTITLE 5. FUNDING NUMBERS Arctic Refuge CO:lStal Plam Terrestrial Wildlife Research Summaries 6. AUTHOR(SI Douglas, D. C, RC}Tlolds, P. E., and Rhode, E. B" editors 7. PERFORMING ORGANIZATION HANE(S) AHO AODRESS{ES) a. PERFORMING ORGANIZATION REPORT U.S. Department ofthe Interior NUMBER U.S. Geological Survey USGSiBRDiBSR·2002-0001 9. SPOHSORrNGfMONITORlNG AGENCY NAME(S) AND ADDRESS{ESj 10. SPOHSORIHG.MONITORING AGENCY REPORT HUMBER U.S. Department ofthe Interior U.S. Geological SUr\'ey 11. SUPPLEMENTARY NOTES 12.1. DISTRIBUTiON/AVAILABILITY STATEMENT 12B. DISTRIBUTiON CODE Release unlimited. Available from the National Technical Information Service, 5285 Port ROy:ll RO:ld, Springfield, VA 22161 (1-800.553-6847 or 703-487-4650). AVlIilable to registered users from the DefenseTechnicallnformation Center, Attn: Help Desk, 8722 Kingman RO:ld, Suile 0944, Fort Belvoir, VA 22060-62 I8 (1-800-225·3842 or 703-767-9050). 13. ABSTRACT (Mal:m\JTl 200 WOrt!!) This report summ:lw-es investig:llions ofkcy terrestrial wildlife spl.:cies that use an appro;<;imate 1.5-million·acre al"C 14. SUBJECT TERMS (Ke)WOl'ds) 15. NUMBER OF PAGES Arctic National Wildlife Refuge, ANWR, 1002 Area, Alaska, North Slope, tundra, ix+ 75 coastal plain, caribou, Porcupine caribou herd, muskmen, polar bear, snow geese, brown bear, petroleum 16. PRICE CODE 17. SECURITY CLASSIFICATION 11. SECURITY CLASSIFICATIOH 19. SECURITY CLASSIFICATIOH 20. LIMITATION OF ABSTRACT OF REPORT OF THIS PAGE OF ABSTRACT Unclassified Unclassified Unclilssified , Unclassified Technical Report Series u.s. Geological Survey TIle Biological Resources Division publishes scientific and technical articles and reports resulting from the research perfonncd by our scientists and partners. These articles appear in professional joumals around the world. Reports are published in two report series: Biological Science Reports and Infonnation and Technology Reports. Series Descriptions Biological Science Reports ISSN I081·292X Informalioll ami Technology Reports ISSN 1081-2911 The series records the significant findings resulting from 1l1~s~ reports are intcnded for publication of book-length sponsored and co-sponsored research programs. They may monographs; synthesis documents; compilations of include extensive data or theoretical analyses. Papers in this conference and workshop papers; important planning and series nre held to the same pccr·rcview and high quality reference materials such as strategic plans, standard operating standards as their joumal counterparts. procedures, protocols, handbooks, and manuals; and data compilations such as tables and bibliographies. Papers in Ihis series arc held to the same peer-review and high quality standards as their journal counterparts. U.S. Geological Survey· Alaska Science Center 1011 E. Tudor Road, MS 701 Anchorage, Alaska 99503 Chier William K. Seitz Production Staff Document Layout and Mary E. Whalen Covcr Dcsign Section I Map Figurcs Jay A. Johnson Digital Distribution James E. I-Iaga and Adeline C. Sheridan Assistancc Cover Photography Coastal plain: A. Thayer; caribou: K. Whitten; muskoxen: M. Elllers; grizzly bcar: H. RC)110Ids; snow geese: 1. Bupp; \'cgctatioll sampling: C. Curby; polar bears: S. Amstrup; tussock cOtlongrass: M. Elllcrs.