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SUSITNA HYDROELECTRIC PROJECT
FINAL REPORT
BiG GAME STUDIES
VOL.IV CARIBOU
KENNETH W.PITCHER
ALASKA DEPARTMENT OF FISH AND GAME
333 RASPBERRY ROAD
ANCHORAGE,ALASKA 99502
APRIL 1987
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Between January 1980 and June ,::~A::e A1as:~~!~;~~~9
contracted with the Game Division of the Alaska Department of Fish and .''
Game (ADF&G)to provide field data and recommendations to be used for f ft]5
assessing potential impacts and developing options for mitigating
impacts of the proposed Susitna Hydroelectric Project on moose,
caribou,brown bear,black bear,Dall sheep,wolf,wolverine,and
belukha whales.ADF&G was only one of many participants in this
program.Information on birds,small mammals,furbearers,and
vegetation was collected by the University of Alaska and private
consulting firms.
Formally,ADF&G ' s role was to collect data which could be used to
describe the baseline,pre-project conditions.This information was
supplemented with data from other ADF&G studies.Baseline conditions
were defined to include processes which might be sufficiently sensi-
tive to either direct or indirect project induced impacts to ~lter the
dynamics of the wildlife populations.The'responsibility of impact
assessment and mitigation planning was assigned by APA to several
private consulting firms.ADF&G staff worked closely with these
firms,but only in an advisory capacity.
The project was cancelled before the impact assessment and mitigation
planning processes were complete.In an effort to preserve the
judge~ents and ideas of the authors at the termination of the proj e.ct,
the scope of this report has been expanded to include material
relating to impact assessment and mitigation planning.Statements do
not necessarily represent the views of the APA or its contractors.
Conjectural statements sometimes are included in the hope that they
may serve as hypotheses to guide future work,should the proj ect be
reactivated.
The following list of reports completely cover all of the Game
Division t s contributions to the project.It should not be necessary
for the reader to consult the many progress reports.
Moose
Modafferi,R.D.1987.Susitna Hydroelectric Project,Big Game
Studies,Final Report Vol.I -Moose -Downstream.Alaska Dept.
of Fish and Game.
Becker,E.F.and W.D.Steigers.1987.Susitna Hydroelectric
Project,Big Game Studies.Final Report,Vol.III -Moose forage
biomass in the middle Susitna River basin,Alaska.Alaska Dept.
of Fish and Game.
B.and J.S.Whitman.1987.Susitna Hydroelectric
Big Game Studies.Final Report,Vol.II Moose
Alaska Dept.of Fish and Game.
ARLIS
1987.Susitna Hydroelectric Project.Big Game
Final Report.Vol.VI -Moose Carrying Capacity
Alaska Dep~.of Fish and Game.
Ballard,W.
Project,
Upstream.
Becker,E.F.
Studies.
Estimate.
w.
Alaska Resources
Library &Information Services
Anch()r~I1f'.Alaska
Caribou
Pitcher,K.W.1987.Susitna Hydroelectric
Studies.Final Report.Vol.IV -Caribou.
and Game.59pp .
Black Bear and Brown Bear
Project,Big Game
Alaska Dept.of Fish
Miller,S.D.1987.Susitna Hydroelectric Project,Big Game Studies,
Final Report.Vol.V -Black Bear and Brown Bear ..Alaska Dept.
of Fish and Game.
Wolf
Ballard,W.B.,J.S.Whitman,L.D.Aumiller,and P.Hessing.1984.
Susitna Hydroelectric Proj ect,Big Game Studies.1983 Annual
Report.Vol.V -Wolf.Alaska Dept.of Fish and Game.44pp.
Ballard,W.B.,J.S.Whitman,and C.L.Gardner.1987.Ecology of
an exploited wolf population in southcentral Alaska.Wildlife
Monographs No.__(In press).
Wolverine
Whitman,J.S.and W.B.Ballard..1984.Susitna Hydroelectric
Project,Big Game Studies.1983 Annual Report:Vol.VII -
Wolverine.Alaska Dept.of Fish and Game.25pp.
Dall Sheep
Tankersley',N.G.1984.Susitna Hydroelectric Project,Big Game
Studies.Final Report.Vol.VIII -Dall Sheep.Alaska Dept.of
Fish and Game.9lpp.
Belukha Whale
Calkins,D.1984.
Final Report.
Game.16pp.
Susitna Hydroelectric Project,Big Game Studies.
Vol.IX -Belukha Whale.Alaska Dept.of Fish and
".
''''__-----------__--_---_-_----_--
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SUMMARY
The Nelchina caribou herd,which ranges over a 20,000 mi 2
area in southcentral Alaska,has been particularly important
because of its size and proximity to population centers.A
proposal to construct a large hydroelectric proj ect which
would include two reservoirs,access roads and assorted
other developments on the Susitna River in the western
portion of the Nelchina range has raised concerns about the
welfare of this herd.Impact studies were conducted between
April 1980 and October 1985 addressing the following
objectives:(1)determination of range use,movement
patterns,migration routes and timing of maj or movements;
(2)evaluation of the popUlation status of the Nelchina
herd;(3)delineation of subherds;and (4)literature
review of impacts of development on caribou and reindeer
populations.The results of these studies are being used to
evaluate potential impacts of project·construction,to make
recommendations to minimize adverse impacts and to evaluate
mitigation measures.The primary methodol.ogy for the study
was the repetitive relocation of radio-collared caribou
along with standardized techniques of popUlation size
estimation and composition sampling.
Distribution was more variable in winter than during other
seasons.Wintering Nelchina caribou ranged from the
Talkeetna Mountains foothills,across the Lake Louise Flat,
through the middle portions of the Gakona and Chistochina
River drainages,along the northwestern slopes of Mount
Sanford in the Wrangell Mountains,northeast through the
Mentasta Mountains and onto the Tetlin Flats.Most
wintering Nelchina caribou were distant from the proposed
impoundment sites.Historical winter ranges in the
Talkeetna Mountains and to the north of the Watana
impoundment area were not used during the study.
Spring migrations to the Talkeetna Mountains calving grounds
from winter ranges to the east included a northwesterly
movement from the Lake Louise-Susitna Lake area south of the
Tyone River into the Talkeetna Mountains,generally in the
area of the Oshetna River.During some years (1980-1983)
substantial numbers of females traversed the upper portion
of the proposed Watana impoundment enroute to the calving
grounds.
During all five years of the study the female segment of the
herd utilized the traditional calving grounds located in the
northern Talkeetna Mountains.Core drainages used during
calving included the Oshetna and Black Rivers and Kosina
Creek.Relocations of females during the calving period
averaged 3,742 feet elevation.During the calving period
radio-collared males were mostly in transit from winter to
summer range.Fidelity to a single calving ground was shown
ii
by 59 of 60 radio-collared females that were monitored for
two or more calving seasons.
Primary summer range for the female-calf segment of the
Nelchina herd during the study period was the northern and
eastern slopes of the Talkeetna Mountains.Two radio-
collared females left the Talkeetna Mountains after calving
and spent the summer north of the Sus i tna River in the
benchlands of the Chulitna Mountains,an area historically
important as both summer and winter range.During summer
male radio-collared caribou were found scattered throughout
the high country of the Nelchina Basin with only small
numbers intermingled with the cow-calf segment.
Movements of Nelchina caribou were variable during the
autumn period with many animals dispersing out of summer
range onto the Lake Louise Flat.More mixing of the sexes
occurred than during calving and summer.
During the rut Nelchina caribou were found from the
Talkeetna Mountains east to the Wrangell Mountains
foothills.Considerable west-east movement usually occurred
during this period.The sexes were generally well mixed.
Relocations of radio-collared caribou during this stUdy
encompassed an area of about 16,237 mi 2 •The northeastern
Talkeetna Mountains are the core area of the Nelchina
caribou herd,containing the calving grounds,summer range
and occasional winter range.The northwestern portion of
the Nelchina range received minimal use by main Nelchina
herd animals during this study while historically it was
important summer and winter range.
The main Nelchina herd was estimated to contain 27,528
animals in October 1985 i composed of 50%females 2:1 year,
27%males 2:1 year and 23%calves.During recent years the
herd has undergone:a growth phase,1950-1960;a peak,1961-
1965;a decline,1966-1973;and another growth phase,1974-
1985.Between 1980 and 1985 the herd grew at about 8%
annually with an additional 4%harvest.Adult survival was
estimated at 0.91 and 0.93 respectively for females and
males from the main Nelchina herd.Between 1980 and 1983
calf survival was estimated to average 0.44 for the first 11
months of life.Hunter harvest has been limited by a permit
system during recent years and the reported harvest has
averaged about 883 animals annually since 1980.
The precipitous decline of the Nelchina caribou herd from
70,000+animals in the early to mid-1960's to <10,000
animals in the early 1970 t S appears to have resulted from
multiple factors.Primary causes probably included
excessive human harvest,increased predation and decreased
calf survival during several severe winters.
-
,...
.iii
Three distinct subherds were identified based on relocations
of radio-collared caribou.Approximately 400 caribou were
estimated to reside year-round in the upper Talkeetna River.
The Chunilna Hills contained a resident group of about 350
caribou.About 1,500 animals occurred year-round in the
upper drainages of the Susitna,Nenana and Chulitna Rivers.
Probable subherds also occurred in the western Talkeetna
Mountains and along the southern slopes of the Alaska Range.
Male and female radio-collared caribou used similar habitats
during the rut and winter seasons when spruce forests were
primarily utilized.During spring,calving,summer and
autumn,habitat use was different between sexes.Males
tended to utilize lower elevation habitats such as spruce
forests and shrublands to a greater extent than females
which more frequently used the highland tundra-herbaceous
habitats.
The proposed Devil Canyon impoundment and transportation and
powerline corridors to the west appear to have little
potential to adversely impact Nelchina caribou as neither
currently nor historically have many caribou occurred in
this region.
The Watana impoundment area has historically been crossed by
large segments of the Nelchina herd both during spring
migration to the calving grounds in the Talkeetna Mountains
and during summer and fall movements to summer and winter
ranges north of the susitna River.Recent crossings of this
nature have been infrequent;however,it is probable that
large scale movements will again resume at some point in the
future.Skoog (1968)considered this region to be the most
important for year-round use by Nelchina caribou.The major
concern with the Watana impoundment i~that the female
segment of the herd will try to cross the reservoir during
spring migration to the calving grounds and that mortalities
will result because of hazardous conditions.
The proposed Denali access road would bisect summer and
winter range for about half of the upper Susitna-Nenana
subherd and would run through historical summer and winter
range for the main Nelchina herd.It is uncertain what
impacts the road would have;however,heavy traffic could
resul t in avoidance by caribou and perhaps some mortality
through caribou-vehicle collisions.
Disturbance from increased aircraft traffic and activities
associated with project construction do not appear to be of
serious concern as most activities would not occur in
important caribou habitats or could be mitigated through
time and area restrictions.Increased access and
development in remote areas of the Nelchina range resulting
from project construction must be considered as potentially
detrimental to the herd.
Most importantly,the Susitna hydroelectric proj ect should
be viewed as one of a number of developments which have or
may occur on the Nelchina caribou range.While no single
action may have catastrophic results the cumulative impact
will likely be a reduced ability of the Nelchina range to
support large nlli~bers of caribou.
iv
v
TABLE OF CONTENTS
Page
S umma.ry-..............................'..................i
List
List
of Tables
of Figures
•••••••••••••••••••••••••••••••••••••e,••
.......................................
vi
vii
Habitat Use
Seasonal Elevation Patterns
Results and Discussion
Distribution and Movements:Main Nelchina Herd
1
3
5
5
24
26
29
31
41
44
45
53
54
59...............................
..........................................
....,-.......................................
...............................................
Decline of the Nelchina Herd
Subherds
Population Size and Composition:Main Nelchina Herd
Mortality/Survival
Personal Communications
References
Potential Impacts of Project Construction
Acknowledgements
Introduction
Methods
vi
LIST OF TABLES
Page
Table 1.Historical range use of0 the Nelchina
caribou herd ~. . . . . . . . . . . . . . . . . . ..15
Table 2.Population estimates of the Nelchina
caribou herd,1955-1985 ............•........25
Table 3.Nelchina caribou herd fall sex and age
composition data 26
Table 4.Reported hunter harvest of the Nelchina
caribou herd,1946-1985 ....•................28
Table 5.Crosstabulation of radio-collared caribou
relocations from the main Nelchina herd
by sex and season .........•.................43
Table 6.Crosstabulation of radio-collared male
caribou relocations from the main Nelchina
herd by habitat and season 43
Table 7.Crosstabulation of radio-collared.female
caribou relocations from the main Nelchina
herd by habitat and season 44
Table 8.Crosstabulation of radio-collared caribou
relocations by habitat and subherd 44
Table 9.Mean seasonal elevations (feet)for
relocations of female and male radio-
collared caribou from the main Nelchina
herd 45
vii
LIST OF FIGURES
Page
Fig.1.Nelchina caribou range with basic
geographic features 2
Fig.2.Distribution of Nelchina radio-collared
caribou during winter,1 November-31 March,
1980-1985 --'..............6
Fig.3.Distribution of Nelchina radio-collared
caribou during winter,1 November 1980-31
March 1981 '............................................7
Fig.4.Distribution of Nelchina radio-collared
caribou during winter,1 November 1981-31
March 1982 _,"...... ...... ........ .. .. .. ..8
Fig.5.Distribution of Nelchina radio-collared
caribou during winter,1 November 1982-31
March 1983 .......'..................................................................9
Fig.6.Distribution of Nelchina radio-collared
caribou during winter,1 November 1983-31
March 1984 '... .... ..10
Fig.7.Distribution of Nelchina radio-collared
caribou during winter,1 November 1984-31
March 19 85 ..".......................................................................11
Fig.8.Division of Nelchina range into areal units
based upon topography,vegetation and
caribou use 13
Fig.9.Distribution of Nelchina radio-collared
caribou during spring migration,1 April-
14 May,1980-1985 ..••....•.......•.•......•....14
Fig.10.Distribution of Nelchina radio-collared
caribou during calving,15 May-10 July,
1980-1985 ...."".. ...... ...... ...... .. .. .. ........ .. .... .. .. .. .. .. .. .. .. .. .. .. .. ......17
Fig.11.Distribution of Nelchina radio-collared
caribou during summer,11 June-31 July,
1980-1985 19
Fig.12.Distribution of Nelchina radio-collared
caribou during autumn,1 August-30
September,1980-1984 21
viii
Fig.13.Distribution of Nelchina radio-collared
caribou during the rut,1-31 October,
1980-1985 .g 0&)••••••"•••••••••,.•••••••22
Fig.140 Distribution of main herd Nelchina radio-
collared caribou during entire study period,
14 April 1980-12 October 1985 •................•23·
Fig.15.Distribution of upper Talkeetna River
radio-collared caribou,18 April 1980-21
June 1982 33
Fig.16.Distribution of Chunilna Hills radio-collared
caribou,18 April 1980-19 November 1984 ......•.34
Fig.17.Distribution of upper Susitna-Nenana radio-
collared caribou,9 May 1980-12 October 1985 ...35
Fig.18.Distribution of upper Susitna-Nenana radio-
collared caribou during calving,15 May-I0
June,1980-1985 II-•••38
Fig.19.Distribution of upper Susitna-Nenana radio-
collared caribou during summer,autumn
and the rut,11 June-31 october,1980-1985 .•..•39
Fig.20.Distribution of upper Susitna-Nenana radio-
collared caribou during winter,1 November-
30 April,1981-1985 .................•..••.•....40
Fig.21.Distribution of upper Susitna-Nenana radio-
collared caribou which were resident in the
Clearwater Mountains area,1980-1985 42
INTRODUCTION
The Nelchina caribou (Rangifer.tarandus)herd,one of 28
herds in Alaska,is found primarily in the large basin
formed by the upper drainages of the Susitna and.copper
Rivers _and surrounded by four mountain ranges:the Alaska
Range,the Wrangell Mountains,the Chugach Mountains and the
Talkeetna Mountains (Fig.1).The Nelchina range contains a
variety of habitats ranging from spruce-covered lowlands to
steep,barren mountains.Human developments are largely
limited to the peripheries of the Nelchina range and consist
primarily of the Alaska Railroad,Parks Highway,Denali
Highway,Richardson Highway,Trans-Alaska Pipeline,Glenn
Highway and associated settlements.
This herd has been a particularly important wildlife
resource because of its proximity to the majority of the
state's population and because access to the herd is
provided by the highway system.Since harvest records were
started in 1946 nearly.112,000 caribou have been reported
taken from this herd.The popularity of hunting for animals
in this herd was shown in 1984 when 12,516 people applied
(including a $5.00 application fee)for 1,900 permits to
hunt for Nelchina caribou.
Because of its importance and accessibility,the Nelchina
herd has been the most intensively studied caribou herd in
Alaska (Doerr 1979).The U.S.Fish and Wildlife Service
began studying the herd in 1948 and continued through 1959.
Since that time the Alaska Department of Fish and Game has
been continually involved with the Nelchina herd through
both research and management programs.Skoog I s (19 68 )
doctoral dissertation,a major work on caribou biology,
dealt largely with the Nelchina herd.
There is currently under study a proposal to construct a
large hydroelectric project on the Susitna River in the
western portion of the Nelchina caribou range.Impacts on
the Nelchina herd of the proposed development,which may
include two dams and impoundments,access roads and railroad
spurs,electrical transmission lines and settlements,were
unclear.Habitat loss to inundation did not appear to be a
serious consideration as less than 1%of the total Nelchina
range would be flooded and Skoog (1968)concluded that
caribou use of the impoundment area was largely limited to
transient animals.The proposed Watana impoundment could
serve as a barrier to migrating caribou.The area along the
Susitna between Deadman Creek and Jay Creek has served as a
migration route both during spring migration to the calving
grounds and during the post-calving shift to summer range
north of the Susitna (Hemming 1971).Factors associated
with ice dynamics on the Watana Reservoir such as ice
shelving (Hansc'om and Osterkamp 1980),ice jams and glare
ice sheets could be a source of mortality to migrating
t
NORTH
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ALASKA RANGE
F.lgure 1.Nelohlna caribou range with basic geographic features.
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3
caribou.Roads,railroads and electrical transmission lines
have all been reported to disrupt caribou or reindeer
movements (Klein 1971,Vilmo 1975,.Cameron et al.1979).
Disturbances associated with construction and maintenance of
hydroelectric facilities could result in reduction ,?f
caribou use of nearby areas as shown for the Prudhoe Bay 011
fields (Cameron et al.1979).The proximity of the
Talkeetna Mountains calving 'grounds to the proposed Watana
impoundment is of concern because of increased human
activity associated with development in the area.Concern
has been expressed that subherds.in the general re.gion of
the proposed impoundments could become more isolated by
construction of the Susitna hydroelectric project.
studies to evaluate potential impacts of construction and
operation of the proposed Susitna hydroelectric project and
to suggest possible mitigation were begun during the spring
of 1980 and continued through fall 1985.Specific
objectives included:(1)determination of range use,
movement patterns,migration routes and timing of maj or
movements with emphasis on movements occurring in the
vicinity of proposed development:(2)evaluation of the
population status of the Nelchina herd including estimates
of herd size,productivity and mortality;(3)delineation
of subherds within the overall range of the main Nelchina
herd:and (4)literature review of impacts of human
development on caribou and reindeer populations.
Complicating the interpretation of data gathered during
short-term studies of caribou range use and migratory routes
is the well-recognized tendency for changes in range use,
particularly winter range (Skoog 1968).Therefore the
analysis of data resulting from t~is study must be
considered in light of historical information.It is
fortunate that considerable information is available on the
Nelchina herd and these data were used extensively in 'this
analysis.
METHODS
Data on range use,timing of movements,migratory routes,
movement patterns and subherd status were collected by
periodic relocations of radio-collared caribou.It.was
assumed that the behavior of radio-collared caribou was
representative of the herd in general and I have no reason
to suspect that this was not true.caribou were captured by
use of immobilizing drugs;etorphine (M-99),xylazine
(Rompun)and acepromazine administered with projectile
syringes (Cap-Chur equipment)shot from a helicopter.
Radio-collars in the 152.000-153.999 MHz range,purchased
from Telonics Inc.,were used.Radio-collared caribou were
relocated from a fixed-winged aircraft (Cessna 180,185 or
PA-18)equipped with two Yagi antennas,one attached to wing
struts on each side of the aircraft.Antenna leads were
4
attached to a right/left switch box coupled to a radio-
tracking receiver/scanner.Animals were located by
balancing the transmitter signal between the two antennas
through use of the left/right switch box to orient the
aircraft and follow the signal.During the study period 85
radio-collared caribou were monitored between 1 and 63
months each for a total of 2,651 individual relocations.
Seasonal periods used for data analysis were:calving,15
May-10 June;summer,11 June-31 July;autumn dispersal,1
August-3D September;rut 1-31 October;winter 1 November-31
March;and spring migration,1 April-14 May.
The study area consisted of the entire range of the Nelchina
caribou herd as detailed in the Introduction (Fig.1).
However we monitored radio-collared animals much more
frequently when they were in the vicinity of the proposed
Susitna hydroelectric development.
Radio-collared animal relocation data were initially
recorded"on a paper map and the associated descriptive
information was entered on a field form.The descriptive
data were keypunched and entered on a computerized data
file.The relocation data were recorded with a computerized
geoprocessor.Specifics of the data management program are
detailed in the Biometrics and Data Processing report by
Miller and Anctil (1981).
A modified version of the aerial photo-direct count-
extrapolation census procedure (Hemming and Glenn 1969,
Davis et al.1979,Doerr 1979)was used to estimate the size
of the main Nelchina herd.This"technique is composed of
three separate procedures:(1)a complete count of all
animals in the post-calving aggregation;(2)composition
sampling of these same animals to determine the number of
females ~1 year;and (3)representative fall composition
sampling to estimate the proportions of females,males and
calves in the herd.Herd size is then estimated using the
female estimate obtained from the post-calving aggregation
count and composition sampling and the estimate of herd
composition obtained in the fall.critiques of this
procedure are available from Davis et ale (1979)and Doerr
(1979).
Actual counts of caribou in the post-calving aggregation
were made by observers from PA-1S Super cub aircraft.Most
caribou were counted visually although when larger groups
(>250 animals)were encountered they were photographed with
hand-held 35 mIn cameras.During the censuses conducted
during this study no extremely large aggregations (>2,000)
of caribou were encountered.
A helicopter (Bell 206B)was used to sample the post-calving
aggregations,the herd during the rut and the herd in April
5
to estimate proportions of females,males and ca~ves.
Groups of animals were approached from the rear until the
sex of each animal older than a calf could be determined
from the external genitalia (presence or absence of the
vulva).
Estimates of mean annual survival rates were made from
radio--collared animals using a formula provided by Trent and
Rongstad (1974).This formula is based on the number of
mortalities experienced by radio-collared animals and the
period of time the radio-collared animals were monitored.
Estimates of calf survival to 11 months of age were made by
multiplying the calf to female ~1 year ratio obtained in
April by the estimate for annual survival of females ~1
year,and then dividing by the ratio of calves to females ~1
year at birth (Fuller and Keith 1981).
RESULTS AND DISCUSSION
Distribution and Movements:Main Nelchina Herd
Winter (1 November-31 March)Winter distribution was the
most variable for any seasonal period ranging from the
Talkeetna Mountains foothills and lower Watana Creek area in
the west to the Chisana River and Tetlin Lake area in the
east (Fig.2).During the winters of 1980-81 and 1981-82
the primary wintering areas were the eastern Lake Louise
Flat and the middle portions of the Gakona and Chistochina
River drainages (Figs.3&4).In winter 1982-83 Nelchina
caribou ranged from the Tetlin Lake-Chisana River area,
through the Mentasta Mountains,along the Wrangell Mountains
foothills,throughout the Gakona and Chistochina-River
drainages and onto the Lake Louise Flat (Fig.5).During
winter 1983-84 the herd divided into three main
concent~ations (Fig.6)with interchange among all groups.
The largest concentration (about 15,000)ranged along the
Wrangell Mountain foothills between the Dadina River and the
headwaters of the Copper River.A smaller group of caribou
(perhaps 2,500)was found along the northeastern slopes of
the Mentasta Mountains.The third group (about 6,5 a 0)
wintered on the Lake Louise Flat,primarily west of Lake
Louise.Winter distribution in 1983-84 was the most
dispersed winter distribution seen during the entire study
period,with Nelchina caribou spread over an east-west range
of about 150 miles.During the winter of 1984-85 most
Nelchina caribou remained in the western portion of the
range,primarily on the western Lake Louise Flat and in the
Talkeetna Mountains foothills (Fig.7).
During winter males tended to be segregated from females
(Fig.2)and used some of the same locations from year to
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#doftaha,.Fla"
)i\
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1 ..81."",1 6 •
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t
'l4 R"",aE\.\.",1 S.
NORTH
8c,le 1:1,808,070
o 100 Km.,I
"'
'I
~.~\~
.~
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Figure ,.Distribution o(Nelchlns radlo-qollared CIU'''OU during wlnter,·1 November 1.880-31 March 1881.·
•=females,_=males.....•
.
Nas
at....e .c~:II'uZ..~W 0 III.
Q 2...~fD .-W~t-...V~~
(I)~~I0.....-...tD as•4-.
at<Pt-;.-%
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'-~1 Q III
~.c:I~as e:E:
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G >III(a:t'G 0.z0~.-z ...'PO
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.c:Ic:e'-II•~4!J'-~••..~•c:~~,,\y.~Q .0
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'-..~-CI II-t.L.•
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o
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r
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/1 TETLIN
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Scale 1:1.688.870
o 100 Km.
I I
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Figure I.Distribution of Nelchlna radio-collared caribou during winter.1 November 1982-31 March 1983.
•=females.-:::males.(0.
:!l
"
(}TETlIN
LAKE
.To~
...
to.\A"(S.
\A~~1 ,.S1 ~)~;l)
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Scale 1:1,666.670
o 100 Km.
I I
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;:)
~
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u
:....•--.c:O·
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)
\\'1:'\~
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Figure •.Distribution of Nelchlna radio-collared caribou during winter.1 November 1983-31 March 1984,.
o=females.-=males.
...
o.
.'"
%.......--:roz
e
~
oo..
o
.t-=.===....
•
IIIo
CD 0
r
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CD
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CD....•.ae•>oz......•..c•
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III•,..-III•E..•=-Q IIu.•
12
year (Figs .3-7).Concentrations of wintering bulls were
found in the area east of the Richardson Highway and north
of Glennallen,the area near Slana and the Gakona and
Chistochina River drainages.
Movements of Nelchina caribou,northeast of the Mentasta
Mountains such as occurred during 1982-83 and to a lesser.
extent in 1983-84,have only rarely taken place.During the
winter of 1965-66 a similar movement occurred and it was
speculated that emigration of Nelchina caribou may have
occurred (Glenn 1967).A similar movement may have also
taken place during 1978-79 as caribou trails were seen going
to the northeast through the Mentasta Mountains and caribou
sightings were reported from the Tok-Tetlin area (R.Tobey,
S.Eide;pers.comm.).Speculation that such movements
outside of "normal lt range are caused by either behavioral or
food-related pressures resulting from high population
densities (Skoog 1968)does not seem appropriate as only one
of these movements (1965-66)occurred during a population
high.
During winters that Nelchina caribou utilized the Wrangell
Mountains foothills,the Mentasta Mountains and the Tetlin
area,they were intermingled with Mentasta herd caribou.
During the winter of 1982-83 a radio-collared Mentasta
animal wintered on the Lake Louise Flat among Nelchina
caribou.Despite this"mixing during winter all radio-
collared animals returned to their original calving grounds
or summer range.
Nelchina caribou have used numerous winter ranges during the
past 30 years (Table 1,Fig.8).Important historical
winter ranges not utilized between 1980 and 1985 were:range
unit 5,located north of the middle portion of the susitna
River;range unit 11,primarily the Talkeetna River;range
unit 12,essentially calving and summer range in the
Talkeetna Mountains;and range unit 15,southeastern
Talkeetna Mountains.There appears to be considerable
winter range available which has not been utilized in"recent
years.
spring Migration (1 April-14 May)The migratory route of
the female segment of the herd from winter range to the
calving grounds in the northeastern Talkeetna Mountains
depends primarily on the location of the winter range.
During the five winters of this study Nelchina caribou used
winter ranges to the east so their general approach to the
Talkeetna Mountains was similar each year,with only minor
variations.This included a northwesterly movement from the
Lake Louise-Susitna Lake area south of the Tyone River (Fig.
9).Entry into the foothills usually took place in the
vicinity of Oshetna River and i.ts confluence with the
Susitna River.During the springs of 1980-1983 substantial
numbers (exceeding 50%in 1982)of the female segment of the
It .lI ~:j;
o 60 Km.I I
River
~.-
t
NORTH
Figure 8.Division of Helchlna range Into areal units based upon topography,vegetation
and caribou use (modified from Skoog 1988).
.-
Cot).
-0
c .
.2 •....•~•.a e':....II••S ..•••••e...•~..
Q II-...•
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15
Table 1.Historical range use of the Nelchina caribou herd
(modified and expanded from Skoog 1968).
Year
51-52
52..;.53
53-54
54-55
55-56
56-57
57-58
58-59
59-60
60-61
61-62
62-63
63-64
64-65
65-66
66-67
67-68
68-69
69-70
70-71
71-72
72-73
73-74
74-75
75-76
76-77
77-78
78-79
79-80
80-81
81-82
82-83
83-84
84-85
85-86
Calving*
Grounds
12
12
12
12
12
12
12
12
12
12
12
12
12
1,5,12
12,8,11
12,8,11
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
12
Summer*
Range
12,5
12,5,15
5,12
5
12,15
5,12,15
5,12
5,12
5,12
5,9,6',12
5,9,6,12
5,12
5,12
5,12
5
5,4
5,4,12
5,12
12,5
5,12
5,12
12,5
12
12
12,5?
12
12
12
12,15
12,15
12,15
12,15
12,15
12,15
Rut *
13,5,12
13,12,15
5,12,13
5,6
12,15,16
5,6
5,6,13,15
5,13,11,12,13
12,15,6
13,15,5,1'1
12,13,6,15
13,15,6,12
5,13,6,12
5,9,13,6
6,9,13
9,11,13
13
12
13
13
12,15
15,13,12
12,13
12,13
13
13
13,7
13,7,8,12
7,16,13
13,12,8,5
7,16
Winter*
Range
13,12
13
13
13
5,12,6,9
5,1,6,11
11,2,5,15
11,15,1,5,6,13
1,11,5,13
5,11,1,2,13
1,6,2,5,11
1,13,2,5,11,15
1,5,6,11
1,5,6
16,13,15
16,13,1,2
16,13,1,4,5
13,7,8,11,2
13
16,13
16,13,15
15,7,13
15,13,12
16,13
13
13,16
13,16
13,16
13,7
13,7
13,7
16,13,7
16,13
13,12,8
*Range units modified from Skoog (1968):see Fig.8.
herd traversed upper portions of the proposed Watana
impoundment enroute to the calving grounds.In 1981 it
appeared,based on sequential relocations of radio-collared
caribou and sightings of tracks and caribou,that many
animals used the frozen Susitna River as a travel route
between the Oshetna River and Kosina Creek.In 1982 the
Susitna was ice-free during spring migration and a small
16
portion of the female segment crossed the river and
traversed the peninsula north of the big bend and then
recrossed the Susitna near the gaging station.In 1983 it
appeared that only a small portion of the female segment was
in the Watana impoundment area during spring migration which
involved fewer animals than during the three previous years.
During the springs of both 1984 and 1985 migrating females
moved south of the proposed impoundment.Movements of
females onto the calving grounds generally occurred during
the first two weeks of May although considerable annual and
individual variation took place.
In spring 1980,1983 and 1985 three radio-collared females
moved down from the Butte Lake area and crossed the Susitna
in the vicinity of Watana Creek.Historically,many animals
used this route to the calving grounds after wintering north
of the Susitna River (Skoog 1968,Hemming 1971).
Most males lagged behind the females and remained on winter
range longer in the spring.Most males did not migrate to
the calving grounds but moved instead to summer range in the
high country throughout the Nelchina basin (Fig.9).
Calving Period (15 May-10 July)Locations of radio-
collared caribou during the broad limits of the calving
period (15 May-10 June)ranged across the northern slopes of
the Talkeetna Mountains from Sanona Creek to the alpine
foothills east of Fog and Stephan Lakes (Fig.10)
encompassing an area of about 3,307 km 2 (1,277 mi 2 ).Mean
elevation of female relocations during this period was 3,742
feet,ranging from 2,300 to 5,800 feet.This does not
precisely portray the exact calving sites as most births
occur from 20-28 May (Skoog 1968)so many of the relocations
were either before or after actual calving.Core drainages
used during calving were the Oshetna and Black Rivers and
Kosina Creek.During the calving period,radio-collared
Nelchina bulls were found generally to the east of the
calving grounds (Fig.10)mostly in transit to summer range.
Since 1949,the first year for which records are available2Nelchinacaribouhaveutilizedanareaofabout1,600 kID
(1,000 mi 2 ),in the northern Talkeetna Mountains,for
calving (Bos 1974,Hemming 1971,Skoog 1968).While the
precise areas utilized have varied,calving has taken place
between about 3,000 and 4,500 feet elevation.Limited
deviations of this pattern have occurred.In 1964 deep snow
delayed arrival at the calving grounds (Skoog 1968)and many
cows apparently gave birth to their calves north of the
Susitna River (Lentfer 1965).In 1965 (McGowan 1966)and
1966 (Glenn 1967)some calving occurred in the Fog-Stephan
Lakes area which is to the west of the normal calving area.
In 1972,following a deep-snow winter,females were late
arriving on the calving grouI:1ds and it was thought that
delayed calving occurred (Bos 1973).During the spring of
•.
J:
l-e:oz
.
rP
~0
1 "'"~G
G
~G
G
~-~_.
•-..
0
Q)0
c•=
r
17.
....
o
~
it..
II
oo
Io
~......
I:
.c
o
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I:.
0 •-•:::I -
.0 ....E-II•iff
Q .•0 •-..•E..
:::I •-a II
I&.•
18
1982,a year with deep snow in the eastern Talkeetna
Mountains,calving took place at lower elevations (P <0.05)
than during other years of the study (mean of 3,100 feet
compared with 3,742 feet during all years of the study).
Shideler (1986)concluded that it is not always possible to
recognize unique characteristics of heavily used geographic
areas or habitats,but when disproportionately large numbers
of animals select an area (such as a calving ground)over a
period of years it must be assumed that this behavior
confers some advantage to the animals.Therefore a loss of
habitat or reduction in access is likely to disadvantage the
population..
Fidelity to a single calving ground was shown by 59 of 60
radio-collared females that were monitored for two or more
calving periods.The single exception was a female that
calved north of the Susitna River and to the west of Deadman
Mountain in 1983.The following two years she calved on the
Talkeetna Mountains calving ground of the main Nelchina
herd.
Summer (11 June-31 July)Primary summer range for the
female-calf segment of the Nelchina herd between 1980 and
1985 was the northern and eastern slopes of the Talkeetna
Mountains (Fig.11)ranging from the Little Nelchina River
to the hills east of Fog and Stephan Lakes,an area of about
3,904 km 2 (1,507 rni 2 ).This was basically an expansion of
the calving grounds utilizing higher elevations and·
peripheral areas.The Oshetna River was the most heavily
used portion of the summer range.At least two radio-
collared females left the Talkeetna Mountains after calving
and crossed the Susitna River in the proposed Watana
impoundment area to summer range in the eastern benchlands
of the Chulitna Mountains.Historically,movements across
the Susitna River after calving were corr~on as the Nelchina
herd has used summer range in both the Talkeetna Mountains
and in the Chulitna Mountains benchlands (Hemming 1971,
Skoog 1968).In 1971 the female-calf segment of the herd
crossed the Susitna River at least four times in May and
June (Pegau and Bos 1972).To my knowledge,main Nelchina
herd caribou have not used summer range north of the Susitna
River to any significant degree since about 1976,although
between about 1951 and 1972 it was utilized in most years
(Table 1).Crossing apparently occurred between Deadman
Creek and Vee Canyon (Skoog 1968).
During summer male radio-collared caribou were found
scattered throughout the high country of the Nelchina Basin
(Fig.11)with only small numbers intermingled with the cow-
calf segment.summering males were found in the upper
Gakona River,the Alphabet Hills,the Clearwater Mountains j
the Chulitna Mountains and benchlands,and throughout the
northern and eastern Talkeetna Mountains.It appeared that
",.,..~"
)P.
100 Km.
A.TETLINVLAKE
•Tok'
~1S'
~~",1 ..S1"
~1S.
'l4 ~~"G~\.\.
t
NORTH
"--------.Scale 1:1,888.670
o
41 o"a"a"1:'/at.
Figure 11.Distribution of NeloMna radio-collared caribou during summer,11 June-31 July,1980-1985.
o =females,_=male 8~~
U).
20
the largest concentration of summering bulls was located in
the southeastern Talkeetna Mountains in the vicinity of
Caribou Creek.
Autumn (1 August-3D September)Movements of Nelchina
caribou during this period were quite variable.
Considerable use of summer range occurred although animals
often dispersed across the Lake Louise Flat and into the
Alphabet Hills (Fig.12).Individual movements were often
extensive with some individuals traversing the Lake Louise
Flat between the Talkeetna Mountains and the Alphabet Hills
and then returning to the Talkeetna Mountains.Some
individuals moved to the north across the Susitna River in
the proposed Watana impoundment area.The amount and timing
of movement out of summer range varied greatly between
years.More mingling of the sexes occurred during this
period than during calving and summer.Movements during
this period were more like dispersals or wanderings than
directed migrations.
Rut (1-31 October)During the study period rutting
Nelchina caribou were found from the Talkeetna Mountains
north to the Butte Lake-Brushkana Creek area and east to the
Wrangell Mountains foothills (Fig.13).Historically
Nelchina caribou have rutted in a wide variety of locations
wi th the eastern Talkeetna Mountains and Lake Louise Flat
being most extensively used (Table 1).The Deadman-Butte
Lakes area was heavily used during years that segments of
the herd wintered or summered in the area.Often,
considerable movement occurs during the rut,usually from
west to east.It appears that habitat type is not a
critical determinant of rutting location but rather rutting
occurs in virtually any area that caribou might be moving
through during that period.The sexes are usually well
mixed during this period (Skoog 1968)although some males
may be apart from the cow-calf segment both early and late
in the month.
Current Distribution (1980-1985)Use of the Nelchina
range by radio-collared caribou from the main herd during
the entire study period is shown in Figure 14.The area
encompassed about 42,055 km2 (16,237 mi Z).On an annual
basis the area utilized was as follows:1980-81,18,341 km2
(7,081 mi 2 );1981-82 22,800 km~(8,803 mi 2 );1982-83,
36,193 km2 (13,974 mi 2 ),1983-84;33,511 km2 (12,939 mi 2 );19~4-85,32,912 km 2 (12,707 mi 2 ).Skoog (1968)considered
the main portion of the Nelchina range to be composed of
about 45,000 km2 (17,5000 mi 2 );however,he did not include
the Wrangell Mountains foothills or the area to the
northeast of the Mentasta Mountains in these calculations as
they were not·utilized to a significant extent during that
period.He included areas in the western portion of the
range that were not utilized during this study.Hemming
(1971)considered the .Nelchina range to be
,"..'"
8eel,1;1.666,670
o 100 Km.
,t
V'
()TETl.IN
LAKE
.Tok
~,,-o.
...-0"'"~~~"
t
\l<"&'
G~\.\."'(»....~
NORTH
Figure U.Distribution of Nelchlna radlo-collar,d urlbol!during .-utumn.1 Auguet-30 September,1980-1984.
•=femalea,_=male ••~...•
22.
Q
C
..
III
(;I
..
::I
"::Io
,Q
.-::I..
"«I..·III II-«I--0 III
(;I E
I II0-•"·III ,...«I-III III
C E-.c «I
(;I -II
«I •Z'-·0 10
co
C CD
0 ..-I
=0
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II ..
Q «I
.Q
.;0 :...u
«I 0..
::I ..
Q l,'I)-Iu...
«I
III
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....
C
«I
",11
."O,~;J Q'\../°1 0 OJ '!l ,~
::l i"J
8'"'~,.j~~
:,;}.~"1 W
:l W!!'!'
;lC:;)
<0
..I"'"".,.....s-r-.>..;'""";;"'.
X
t-a:oz
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(t)
'i
('l
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23.
as .
I:"III
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10
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as CD
e ....
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ase
II
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~.<
Q
II.
........
o
o
I
o
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III
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I:
.
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(
24
composed of about 52,000 km 2 (20,000 mi 2 )at the time of his
work in the area.
The northern and eastern Talkeetna Mountains are the core of
the Nelchina caribou range.The herd has shown near-perfect
fidelity to the calving grounds located in this region.The
Talkeetna Mountains are also the primary summer range and
have been used on occasion as winter range (Skoog 1968).
Locations of winter ranges are the most variable and during
this stUdy have included the Lake Louise Flat,Gakona and
Chistochina River drainages,Wrangell Mountains foothills,
Mentasta Mountains and area to the northeast,and the
Talkeetna Mountains foothills.The northwestern portion of
the Nelchina Range,including drainages of the upper
Chulitna,Nenana and Susitna Rivers,received minimal use by
main Nelchina herd animals during the stUdy period while
historically it was important summer and winter range.
PopUlation Size and Composition:Main Nelchina Herd
Annual censuses of the main Nelchina herd were conducted
during this study and the resulting estimates,as well as
prior estimates of herd size,are presented in Table 2.
These data indicate that in recent years the herd has
experienced a growth phase,1950-1960;a peak,1961-1965;a
decline,1966-1973;and then another growth phase,1974-
1985.Census methods do not always produce precise
estimates and,in retrospect,certain estimates (e.g.1973,
1976,1977,1978)are likely in considerable error.
Indicated growth between years is much greater than
biologically possible without immigration,an unlikely
possibility.The 1984 estimate was probably low,the result
of nonrepresentative fall composition data.However when
the complete series of estimates is examined a strong trend
of herd growth since the early to mid-1970's is apparent.
The observed exponential rate of annual increase (r),based
on regression of natural logs of the unadjusted -series of
population estimates from 1972-1985 (Table 2),was 0.10.
For the years 1980-1985,r =0.07.During the later period
an additional 4%of the herd·(primarily males)was
harvested annually.
Watson and Scott (1956)provided the first reasonable
estimate of total popUlation size for the Nelchina herd in
1955.Skoog (1968)concluded from fragmentary reports from
early explorers that the Nelchina herd was at a high level
during the mid-1800's.By 1900 the herd had declined to
fairly low numbers and probably remained that way until the
1940's or 50's when herd growth began (Hemming 1975).Skoog
(1968)felt that the herd probably was never below about
10,000 animals.
composition sampling was conducted during the rutting
period,in early October,of each year of the study (Table
"-
25
3).The ratio of males ~1 year to 100 females ~1 year was
relatively consistent,ranging from 54 to 62 except for 1984
(40)..This was likely an erroneous estimate resulting from
misclassification or nonrepresentative sampling.The ratio
of calves to 100 females ~1 year varied greatly,ranging
from 27,the lowest recorded since 1962,to 54,one of the
three highest values ever recorded for the Nelchina herd.
The reason for the variability in calf production and/or
survival to 5 months of age is unknown.
Table 2.Population estimates of the Nelchina caribou herd,
1955-1985.
Total Number of Number of Number of
Year Estimate Females Males Calv'es
1955 40,000
1956 36,240
1962 71,000
1967 61,142
1972 8,094 4,954 1,674 1,466
1973 8,136 4,913 1,341 1,882
1974*10,245
1976 8,081 4,979 1,663 1,439
1977 13,936 7,509 2,868 3,559
1978 18,981 9,866 4,429 4,686
1980 18,713 9,164 5,673 3,876
1981 20,694 10,154 6,184 4,356
1982 21,356 10,199 5,650 5,507
1983 24,838 13,212 8,046 3,580
1984 24,095 13,912 5,495 4,688
1985 27,528 14,121 7,464 6,293
*Count of postcalving aggregation only,no extrapolation.
Current ADF&G management obj ectives for the Nelchina herd
include:(1)restricting the harvest until a population
level of 30,000 animals older than calves is reached,(2)
maintaining a minimum sex ratio of 25 males/100 females,(3)
providing for the greatest opportunity to participate in
hunting caribou,and (4)providing for an optimum harvest of
caribou.Management objectives are expected to be
periodically reviewed as additional information on herd
status,range condition and resource demand and allocation
are obtained.
Currently the Nelchina herd contains about 6%of the total
statewide caribou population (410,000-450,000).It is
exceeded in size by the large Western Arctic and P0rcupine
26
herds in northern Alaska and is slightly smaller than the
Alaska Peninsula and Mulchatna herds in southwestern Alaska.
Historically,the Fortymile herd has been much larger than
the Nelchina 'but currently numbers about 50%as many
animals.
Table 3.Nelchina caribou herd fall sex and age composition
data.
Cows Calves Bulls
Year N 5\,N %/100 N %/100.,
cows cows
1980 402 49 170 21 42 249 30 62
1981 797 49 342 21 43 485 30 61
1982 413 48 223 26 54 229 27 55
1983 705 53 191 14 27 429 32 61
1984 2011 58 678 20 34 794 23 40
1985 1060 50 484 23 46 574 27 54
Mortality/Survival
Natural mortality Between July 1980 and October 1985,85
radio-collared caribou were monitored from one to 63 months,
totaling 2,234 caribou-months,thereby allowing estimates
of annual survival rates to be made.The radio-collared
caribou included 56 females and 16 males from the main
Nelchina herd and 13 females from the upper Susitna-Nenana
subherd.
For females from the main Nelchina herd 12 deaths of radio-
collared caribou were attributed to natural causes,2 deaths
appeared to be the result of crippling loss from hunters or
abandoned hunter kills,3 deaths were the result of legal
hunter kills and there were four assumed radio failures,
only one of which was confirmed.The mean annual estimated
survival rate of females from the main Nelchina herd,
considering only deaths attributed to natural causes,was
0.91 (0.86-0.97;95%C.!.).If the two crippling losses or
abandoned hunter kills·are inclUded,an estimate of 0.90
(0.84-0.96;95%C.I.)-is derived for mean annual survival.
..
27
Among radio-collared males from the main Nelchina herd two
natural mortalities were recorded and it could·not be
determined if two additional deaths resulted from natural
causes or were from crippling loss.Considering only the
known natural mortalities the estimated mean annual survival
rate was 0.93 (0.77-0.99:95%c.r.).However,if all four
deaths are considered,estimated survival was 0.86 (0.69-
o.96;95%C.r.) .
Among radio-collared females from the upper Susitna-Nenana
subherd three deaths occurred.All were attributed -to
natural causes.-In addition,two radio collars were assumed
to have failed.The three natural mortalities resulted in
an estimated mean annual survival rate of 0.86 (0.66-0.97:
95%C.I.).
Monitoring flights were not frequent enough to always
precisely determine causes of death for the mortalities
which occurred among the radio-collared caribou.Among the
17 mortalities which were considered to have been from
natural causes wolves (Canis lUpus)were suspected (although
not confirmed)in 14 cases.A radio-collared male was
thought to have died from an antler wound inflicted by
another bull during the rut.A radio-collared female died
during the calving period:however,the carcass was never
examined on the ground.Cause of the other mortality could
not be determined,but because the animal died distant from
human activities it was considered a natural mortality.
Calf survival from birth to 10.5 months of age was estimated
for four cohorts (1980-1983)based on an assumed birth rate
of 0.66 calves per cow ~1 year (Skoog 1968,Bergerud 1978):
observed ratios of calves per cows obtained during April
composition sampling:and estimated survival of females
between the calving season and the time composition sampling
occurred (Fuller and Keith 1981).Survival estimates for
the four cohorts were:1980,0.43:1981,0.58:1982,0.54:
and 1983,0.19.
Hunting mortality:Harvest by hunters has been an important
mortality factor of Nelchina caribou.Since record keeping-
began in 1946 over 111,000 caribou have been reported killed
by hunters (Table 4).Between 1946 and 1955 fairly
restrictive regulations were in effect,limiting harvest to
a single animal per hunter.From -1956 through 1971
regulations became more liberal with multi-animal bag limits
(maximum of four caribou in 1964)and long seasons (nearly
eight months in 1971).More restrictive regulations
consisting of single animal bag limits and short seasons
were in place from 1972 through 1976.Beginning in 1977 and
continuing through the present,harvests have been regUlated
by a limited permit system.
Table 4.Reported hunter harvest of the Nelchina caribou
herd,1946-1985.
28
Regulatory
Year
Harvest %Females Permit Permits
in Harvest Applications Issued
1946-47
1947-48
1948-49
1949-50
1950-51
1951-52
1952-53
1953-54
1954-55
1955-56
1956-57
1957-58
1958-59
1959-60
1960-61
1961-62
1962-63
1963-64
1964-65
1965-66
1966-67
1967-68
1968-69
1969-70
1970-71
1971-72
~972-73
1973-74
1974-75
1975-76
1976-77
1977-78
1978-79
1979-80
·1980-81
1981-82
1982-83
1983-84
1984-85
Total
200
200
300
350
500
525
450
700
2,000
4,000
3,500
2,500
3,500
4,000
5,500
8,000
3,500
6,300
8,000
7,100
5,500
4,000
6;000
7,800
7,247
10,131
555
810
1,036
806
822
360
539
630
621
901
861
969
1,063
111,776
3
7
15
72
27
28
25
30
34
42
31
39
34
33
29
35
40
51
37
53
28
33
34
31
26
22
21
14
21
18
14
14
16
1,383
2,775
5,600
6,841
6,819
9,110
9,720
12,516
750
1,000
1,300
1,300
1,601
1,750
1,750
1,900
,..'
29
As previously mentioned,herd growth based on population
estimates averaged about 8%annually (r =0.07)between 1980
and 1985.Population projections during this period,based
on estimates of calf recruitment,natural mortality and
hunter ki~ls produced annual herd growth estimates of only
about 4%.It seems likely that one or more of the estimates
of population vital statistics are in error.Hunter harvest
estimates are undoubtedly low as they are based only on the
reported harvest and do not include unreported kills,
illegal kills and crippling loss.Estimates of natural
mortality of adults may be high if radio-collared animals
die at a higher rate than uncollared caribou.I wondered if
wolves might have keyed in on collars,thereby inflating the
natural mortality estimates.
Decline of the Nelchina Herd
Between the early to mid-1960's and the early 1970's the
Nelchina herd declined from a high of 71,000.(Siniff and
Skoog 1964)to possibly 90,000+(Van Ballenberghe 1985)down
to 10,000 animals or less (Bos 1975).Several authors have
analyzed available population data to try and determine
probable causes of the decline (Bergerud 1978, 1980,1983;
Bos 1975;Doerr 1979;Van Ballenberghe 1985).Bos (1975)
suggested that egress of caribou to other ranges may have
played a role in the decline.Bos (1975)also presented
data suggesting that recruitment of calves had declined;he
felt that severe weather and increased wolf predation were
the most likely causes.Doerr's (1979)analyses suggested
that wolf predation and human-caused mortality (hunting)
played influential roles in the decline.He discounted
emigration and felt that additional factors related to
quality of the range,such as decreased conception rates,
increased natal and post-natal mortality rates and decreased
natural survival of calves also impacted popUlation
dynamics.According to Bergerud (1978,1980,1983),wolf
predation,particularly on calves,and excessive human
harvest were the primary causes of the decline.Bergerud
based his argument largely on strong negative correlations
between wolf abundance and calf recruitment as indicated by
cohort analysis of age structure data from the harvest.Van
Ballenberghe (1985)downplayed the importance of wolf
predation in the decline,stating that poor survival of
calves due to severe winters,and poor survival of adults
because of hunting mortality were important factors in the
decline.
I have reviewed available data to try and determine the most
likely cause(s)of the decline.My personal experience with.
the Nelchina herd is limited to the period 1980-1985 and I
realize that changes in wolf and caribou distribution,
behavior and relationships may have occurred since the
period of the decline.I also realize that the historical
...._----_._-----,-~----------------.......------_......_-
30
data base,particularly in regard to caribou numbers,wolf
numbers and harvest data,is imprecise and incomplete.
Emigration of Nelchina caribou to other ranges probably was
not a cause of the decline (Doerr 1979,Van Ballenberghe
1985).Glenn (1967)reported movements of Nelchina caribou
beyond established ranges;these caribou were thought not to
have returned (Bos 1975).I have since seen similar
movements of Nelchlna caribou,documented by tracking radio-
collared animals,all of which returned to the Nelchina
range (Pitcher 1984,1985).
High levels of harvest by hunters are generally acknowledged
as being a contributing factor in the decline.Excessive
harvest appears to have been particularly important late in
the decline.About 10,000 caribou were killed by hunters in
1971-72,a figure similar to total population size in 1972.
Nearly 56,000 caribou were reported killed during the
approximate period of the decline (1964-1972).However,if
unreported kills,illegal kills and crippling loss are
considered the total becomes much higher.
Wolf numbers on the Nelchina range,which were at low levels
during the 1950's because of wolf control activities,
increased during the 1960's.There is some disagreement on
numbers of wolves present during this period (Rausch 1967,
1969;Van Ballenberghe 1985);however,there were probably
considerably more present during the decline than during the
previous caribou growth phase.Bergerud (1978,1980)
provided strong correlations between wolf abundance and calf
caribou recruitment,primarily based on the strength of
cohorts in samples of aged individuals in the harvest.In
order for this to have occurred,wolves must have strongly
selected for calves over other age classes.Recent wolf
studies in the Nelchina basin have not indicated selection
by wolves for calves over older age'classes (Ballard et ale
1981).Examination of serial composition data (July,
October and April)for the Nelchina herd indicate that
normally up to about 50%of the total first year mortality
occurs during the first 1.5 months after birth.In recent
years few wolves have been present on the calving grounds
and summer range 'in the Talkeetna Mountains.This indicates
to me that wolves have little to do with early mortality of
caribou calves in the Nelchina herd,while the Ballard et
al.(19S1)data suggest that wolves are not highly selective
for calves during other seasons.Regardless,wolf numbers
during the period of the decline were considerably greater
than during earlier years when the herd was growing and it
is probable that predation on caribou of all age classes was
a contributing factor in the decline.
Severe winters also probably contributed to the ·decline.
Three severe winters occurred during the period of decline
and one occurred shortly before the decline became
31
established (Van Ballenberghe 1985).The lowest values for
spring...calf/100 cow ratios all followed severe winters
(1961-62 =18,1966-67 =5,1971-72 =16)".No spring
composition data were collected in the spring of 1966,the
other severe winter.
When the caribou population on the Nelchina range was at its
peak,the density was high,perhaps approaching 4 qr 5
animals/mi 2 .Examination of vegetation plots in 1970 and
1971 indicated that the lichen flora had deteriorated over
the previous 10 years .(Pegau and Hemming 1.972).Skoog
(1968)felt that food was not limiting growth of the
Nelchina herd when it was at high densities.Bergerud
(1980)presented a convincing argument that mainland caribou
herds are not food-limited,at least from a density-
dependent standpoint,because they are able to utilize a
wide variety of plant species and are able to move about.
However I do not believe high population density and reduced
availability of preferred food items should be completely.
dismissed as possible contributing factors in the decline of
the Nelchina caribou herd.
In retrospect,it seems likely to me that the decline of the
Nelchina herd from the 70,000-90,000+level to 10,000 or
less was likely due to a combination of causes,with human
harvest the leading factor.Both increased wolf numbers,
which probably resulted in increased mortality rates of all
age classes,and extremely severe winters (three of the four
most severe winters in the past 25 years occurred during the
decline)likely contributed to the reduction.It does not
appear possible to rank these two factors according to their
importance in the decline.High population density and
range deterioration should also be considered as possible'
contributors to the decline.Perhaps anyone or two of
these factors might have caused a decline of lesser
magnitude but the cumulative impact of all factors during a
limited time span likely caused this major population crash.
Subherds
Eide (1980)suspected that several subherds existed within
the overall range of the Nelchina herd.In these subherds
females calved in areas other than the Talkeetna Mountains
calving grounds used by the main Nelchina herd.He based
this conclusion on sightings and reports of animals,
inclUding calves,in these locations during all seasons
including the calving period.Locations of these possible
subherds were the Watana Creek Hills (upper Susitna-Nenana
drainages),the upper Talkeetna River,Chunilna Hills and
the Alaska Range.Because of their proximity to the
proposed Susitna hydroelectric proj ect,radio collars were
placed on animals in three of the suspected subherds:the
upper Talkeetna River,Chunilna Hills and upper Susitna-
Nenana River drainages.Information on other potential
------------------------------
32
subherds within the Nelchina range was obtained from
observations made during this study and from reports from
other biologists and the pUblic.
Upper Talkeetna River Two adult females and one adult male
were collared in the headwaters of the Talkeetna River on 18
April 1980.These animals were relocated a total of 50
times over the next 26 months and were always found in
drainages of the upper Talkeetna River or in the upper
reaches of the nearby Chickaloon River (Fig.15).One
female was seen with a calf in 1980 and both were observed
with calves in 1981.The male spent the summer of 1980 in
the mountains west of the Talkeetna River and then shed his
collar in the upper Talkeetna River in November 1980.I
have seen,incidental to radio-tracking flights,small
groups of caribou including cows and calves in most of the
side drainages of the upper Talkeetna River.Females from
this group did not appear to aggregate either during calving
or post-calving as did animals from the main herd.One
radio-collared female was observed with a young calf in a
high (5,800 feet)snow-covered cirque far from other
caribou.This appeared to be similar to predator avoidance
behavior described by Bergerud et al.(1984a).No attempt
was made to census this subherd;however,based on
observations made during radio-tracking flights I estimated
this resident group of animals at about 400.Historically
(1956-57,1961-64)major segments of the Nelchina herd
wintered in the Talkeetna River area (Skoog 1968).
Chunilna Hills While only limited information (21
relocations from three radio-collared caribou)was obtained
from this group it did appear to be a resident subherd as
these animals remained within a local area (Fig.16).Both
radio-collared females gave birth to calves in the area.
The largest group of caribou seen in the Chunilna Hills was
about 125 animals although I have received unconfirmed
reports of 200-300 caribou in that area.Perhaps as many as
350 "animals were resident in the Chunilna Hills area.Skoog
(1968)made no mention of either resident animals or
significant use by Nelchina animals in the Chunilna Hills.
He said that caribou use was limited to a few wandering
bands.No radio-collared caribou from the main Nelchina
herd were found in the Chunilna Hills during this study
(Fig.14)..
Upper Susitna-Nenana This region,which is located in the
northwestern corner of the Nelchina range contains the
largest subherd of resident caribou.Over a 5.5-year period
14 radio-collared caribou from this area were relocated a
total of 257 times (Fig.17).Primary areas utilized
included the Clearwater Mountains,the Butte Lake-Brushkana
Creek area and the Chulitna Mountains.
Two attempts were made to estimate the size of this subherd.
33.
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Figure 17.Distribution of upper Susltna-Nenana radio-collared caribou.9 May 1980-·12 October 1986.
•=fenial e s.*=males.
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36
From 8 through 11 October 1982 a total count of caribou in
the area north and west of the Susitna River above Gold
Creek and in the Clearwater Mountains was attempted.The
western and northern boundaries were the Parks Highway and
the Alaska Range.Reasonable snow cover allowed us to
concentrate efforts in areas where tracks were present;it
also increased sightability of animals.The count took
place during the rut when most animals were found in groups
(5-75 animals),again improving sightability.A total of
2,077 caribou was counted.
Several factors may have affected the accuracy of this
census.Periods of bad weather resulted in the count being
spread over a five-day period when it could have been
completed in two days,thereby increasing the likelihood of
movement which could have resulted in either double
counting,undercounting or a combination of both.
Potentially the most serious complication was the movement
of perhaps 10%of the main Nelchina herd through the
southeastern corner of the study area during the counts.
The migratory route of these animals as they left the
Talkeetna Mountains,crossed the Susitna River and moved
through the study area·was relatively distinct because of
trailing in the snow.Animals encountered along this route
were not included in the counts.Therefore,resident
animals which may have been in the area were not included,
which would have resulted in an underestimate.Conversely,
animals from the main herd which may have dispersed from the
migration route would have been counted,thereby inflating
the subherd estimate.During the time the count was made
two radio collars were placed on adult females within the
count area.-One of these radio-collared females
subsequently joined the main Nelchina herd and migrated to
the Talkeetna Mountains calving grounds in the spring.The
next fall she again migrated through the range of the upper
Susitna-Nenana subherd.Thus it appears she was actually a
main herd animal that migratE?d through the range of the
upper Susitna-Nenana subherd during at least two years.It
is likely that other main herd animals also follow this
pattern (another animal collared in 1980 showed a similar
pattern until killed by wolves).Therefore this census
attempt probably overestimated subherd size.
Another attempt at directly counting the subherd was made on
4 and 5 April 1984.Snow accumulation in the area was above
normal at this time and caribou were concentrated in several
locations.We counted 913 caribou in the area with major
concentrations found in the following areas:hillside to
the east of the middle portion of Brushkana Creek (352);
foothills to the east of Butte Lake (198);Rusty Hill ridge
between Valdez Creek and the Susitna River (199);and
Reindeer Hills (57).
37
This count was probably considerably low as counting
conditions were poor in places and not alL.·animals were
within the area counted.Some knolls and ridges were
windblown and caribou appeared to select these areas,
probably because forage was readily accessible.Animals in
these windblown areas were difficult to see and count.At
the time of the census seven of eight radio-collared caribou
from the subherd were within the count area.None of 35
radio-collared caribou from the main herd were found within
50 miles of the count area and most were over 100 miles to
the east;therefore it was unlikely that main herd animals
were included in the count.
Because of the several factors that affected the count (poor
counting conditions,subherd animals outside of the count
area and low probability of main herd animals being included
in the count),it is likely that the count was a substantial
underestimate of subherd size.The previous count was
likely a substantial overestimate of subherdsize.It seems
reasonable to assume that the two counts are likely outer
bounds of the true population size.The upper Susitna-
Nenana subherd probably ranged between 1,000 and 2,000
caribou with the mid-point of 1,500 being a reasonable
estimate.
All observations of upper Susitna-Nenana subherd radio-
collared caribou encompassed an area of about 5,525 km 2
(2,133 mi 2 ).Distribution of the subherd extended west from
the Clearwater Mountains and headwaters of the Susitna River
across Monahan Flat along the Alaska Range to Reindeer
Hills,and also the Butte Lake-Brushkana creek-upper Deadman
Creek complex and the Chulitna Mountains (Fig.17).
Calving distribution of females (Fig.18)was quite
dispersed and occurred in three general regions:headwaters
of the Susitna River and Clearwater Mountains,Butte Lake-
Brushkana Creek area,and the Chulitna Mountains.This
dispersed calving·is in contrast with that of the main
Nelchina herd where females formed a relatively cohesive
group and gave birth to their calves in a restricted
geographic area.Summer-fall range was similar to the
calving area (Fig.19)although animals were often found at
higher elevations.Primary wintering areas were in the
Butte Lake-Brushkana Creek area,Monahan Flat and along and
to the east of the Susitna River above the Denali Highway
(Fig.20).Some winter use of the Chulitna Mountains
occurred,.particularly on the northern slopes,although
during deep-snow winters such as 1983-84 nearly all animals
moved to the east.During deep-snow conditions caribou
concentrated in the hills both east and west of Butte Lake
and on Rusty Hill ridge between Valdez Creek and the Susitna
River.It appeared that wind-blown areas in this higher
terrain were being utilized as feeding sites.
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The Chulitna Mountains were primarily.calving and summer
range although -some caribou -wintered--there,-pa-rticula:tly
during years with moderate snow accumulation.Half of the
radio-collared caribou from this subherd spent time in the
Chulitna Mountains with most migrating to the east for the
winter.As previously mentioned,some bulls from the main
Nelchina herd also spent summers in the Chulitna Mountains
(Fig.11).
Nearly all animals using the Clearwater Mountains were
residents spending the entire year in the area and could be
considered a separate subherd from the rest of the upper
susitna-Nenana animals (Fig.21).Only one radio-collared
subherdanimal that was not a resident of the Clearwater
Mountains spent time in the area.During three years of
monitoring this female spent part of one winter in the area.
Bulls from the main herd also spent summers in the
Clearwater Mountains.Based upon counts obtained during the
two censuses it appeared that about 350-400 caribou were
resident in the Clearwater Mountains.
Local resident groups of caribou likely occur in other areas
of the Nelchina Basin.A subherd(s)is probably present in
the western Talkeetna Mountains.A biologist flying moose
(Alces alces)surveys has frequently seen caribou,including
cows and calves,in the alpine area between Willow and
Little Willow Creeks (Ron Modafferi,pers.comm.).I have
also received unconfirmed reports of caribou in the Wells
Mountain area,possibly the site of another subherd.After
receiving reports of animals in the upper Gakona-Chistochina
Rivers area a reconnaissance survey of the area was flown on
9 June 1981 during which a group of 20 cows was seen,some
of which had young calves,as well as a group of 12 bulls.
A radio-collared bull from the main Nelchina herd spent two
summers in this area and many animals from the main herd are
often present during fall and winter.This is probably a
small subherd which-mingles seasonally with main-herd
caribou.I have also received unconfirmed reports of
females with calves along the southern slopes of the Alaska
Range between the Clearwater Mountains and the Richardson
Highway during summer.I have only seen bulls but have not
rigorously surveyed the area.
Habitat Use
I examined habitat use by recording vegetation type on each
low-level relocation of radio-collared caribou during the
period 1980-83.vegetation type was that which was
predominate in an area around the animal.The vegetation
classifications were simplifications of Viereck and
Dyrness 1 s (1980)level I categories.My inability to
precisely classify vegetative cover ·from aircraft plus the
fact that ground vegetation was covered by snow for much of
~
':f"
':l
':)~...J:!.l
~..•
,~.)
~~)
-":CLEARY/T ER NT8·-
~B ••'.1:1,111.110 .0 Km.~0 II
':J
'J
an Flata
'~~:)
CPBell•
Lake
/"-"""""'1
....tg.
~
....~t-
.;:,'>CJ~
t
NORTH
Figure 21.Distribution of upper Sueltna-Nonana radlo-oollared caribou which were resident In the
Clearwater Mountains area,1980-1986,•=female ••*=males.
,..
...
I\)•
43
the year precluded more precise classifications in most
cases.Categories included:spruce forest (virtually no
use of deciduous or mixed forest types was seen),tundra and
herbaceous combined,shrublands and bare substrate.
Male and female radio-collared caribou from the main
Nelchina herd did not utilize habitat types in similar
proportions (P =0.002)on an annual basis.Both sexes
used similar habitats during the rut (P =0.763)and winter
(P =0.410)but not during other seasons (P <0.05).Males
were found more often in spruce forest while females
occurred more frequently in tundra-herbaceous and shrublands
(Table 5).This largely reflects the tendency of males to
remain longer on winter range in the spring (Fig.9)and to
spend spring and summer at lower elevations (Table 9).Both
males and females utilized habitats differently (P <0.001)
by season.Males largely utilized spruce forests from the
rut through the calving period while shrublands and tundra-
herbaceous were the preferred habitats during summer.
During autumn dispersal all habitats were utilized (Table
6).Females showed a similar seasonal pattern except they
moved out of the spruce forest and into shrublands and
tundra-herbaceous habitats during calving (Table 7).
Tabie 5.Crosstabulation of radio-collared caribou
relocations from the main Nelchina herd by sex and habitat.
Spruce Tundra-Bare
Sex Forest Herbaceous Shrubland Substrate
Female 296 (44%)176 (26%)167 (25%)34 (5%)
Male 99 (60%)26 (16%)33 (20%)8 (5%)
Chi-Square -14.4,D.F.-3,P -0.002
Habitat use by animals from the main Nelchina herd differed
(P =0.000)from that of animals from the upper Susitna-
Nenana,Talkeetna River and Chunilna Hills subherds (Table
8).Spruce forest was the major habitat utilized by main
herd animals while tundra-herbaceous was the primary habitat
utilized by subherd animals.
44
Table 6.Crosstabulation of radio-collared male caribou
relocations from the main Nelchina herd by habitat and
season.
'"
Spruce Tundra-Bare
Season Forest Herbaceous Shrub land Substrate
Calving 12 (63%')3 (16%)4 (21%)0 (0%)
Summer 0 (0%)9 (41%)12 (55%)1 (4%)
Autumn 7 (23%)5 (17%)14 (47%)4 (13%)
Rut 9 (90%)0 (0%)1 (10%)0 (0%)
Winter 30 (88%)2 (6%)1 (3%)1 (3%)
spring 41 (80%)7 (14%)1 (2%)1 (2%)
Chi-Square =86.4,D.F.=15,P =0.000
Table 7.Crosstabulation of radio-collared female caribou
relocations from the main Nelchina herd by habitat and
season.
Spruce Tundra-Bare
Season Forest Herbaceous Shrub1 and Substrate
Calving 3 (2%)67 (41%)92 (56%)1 (1%)
Summer 0 (0%)43 (72%)16 (27%)1 (2%)
Autumn 23 (25%)46 (49%)14 (15%)10 (11%)
Rut 29 (76%)1 (3%)6 (5%)2 (5%)
Winter 94 (80%)4 (3%)5 (4%)14 (12%)
Spring 147 (73%)15 (7%)34 (17%)6 (3%)
Chi-Square =443.5,D.F.=15,P =0.000
Table 8.Crosstabulation of radio-collared caribou
relocations by habitat and subherd.
Spruce Tundra-Bare
Herd Forest Herbaceous Shrubland Substrate
Nelchina 395 (47%)202 (24%)200 (24%)42 (5%)
u.Sus-Nen 2 (2%)76 (63&)35 (29%)8 (7%)
Talk.R.1 (2%)44 (90%)2 (4%)2 (4%)
Chun.Hills 0 (0%)21 (81%)5-(19%)0 (0%0
Chi-Square =215.6,D.F.=9,P =0.000
..
45
Seasonal Elevation Patterns
Male and female radio-collared caribou from the main
Nelchina herd were found at different (P <0.02)elevations
during all but the autumn and rut periods (Table 9).During
the spring and calving periods males lagged far behind the
females,remained longer on winter range,and then spent
much of the Summer in the lower shrublands.Maximum mixing
of the sexes occurred during autumn dispersal and the rut,
resulting in use of similar elevations.Males were found in
'low-elevation spruce forests during winter.Females were
found at highest elevations during summer while males went
highest during summer and autumn.
Table 9.Mean seasonal elevations (feet)for relocations of
female and male radio-collared caribou from the main
Nelchina herd.
Season Females Males P
Calving 3,742 2,948 0.000
Summer 4,032 3,444 0.000
Autumn 3,771 3,605 0.389
Rut 2,649 2,523 0.424
winter 2,791 2,498 0.012
Spring.2,591 2,219 0.000
POTENTIAL IMPACTS OF PROJECT CONSTRUCTION
The proposed Susitna hydroelectric project is located in the
western portion of the Nelchina caribou range.The Devil
Canyon impoundment,with its related developments and
transportation routes and powerlines to the west does not
appear to be of serious concern.Neither during this study
(Fig.14)nor historically have many caribou from the main
Nelchina herd occurred in this region.No direct access
routes to important caribou habitats would be created.The
small Chunilna Hills subherd (Fig.16)resides a short
distance to the southwest of the Devil Canyon impoundment
site.However,it does not appear that either the
impoundment or associated developments would occur in
habitat occupied by this group of caribou.Elevations of
relocations of Chunilna Hills radio-collared caribou ranged
between 2,000 and 3,800 feet which is higher than all
proposed Devil Canyon developments except a quarry site.
46
The proposed Watana impoundment and associated developments
such as access and construction roads,the proj ect
settlement and airstrip and borrow pits present a somewhat
different situation.The Watana impoundment would intersect
a major migratory route which was heavily utilized in the
past and has been moderately used during the past five
years.The Watana development would be in close proximity
to important caribou habitats and would result in increased
human access to these areas.
Potential adverse impacts generally fall into five broad
categories with some overlap between groupings:(1)direct
habitat loss,(2)harassment,(3)avoidance of development,
(4)disruption of movements,(5)increased mortality,and
(6)increased human access to important habitats.
Direct habitat loss does not appear to be a serious impact
of proj ect construction.Most of the area that would be
altered by development such as the impoundments,borrow
sites,roads,villages and the airstrip are not heavily
utilized caribou habitat.Skoog (1968)stated that the area
to be flooded by the Watana impoundment was used primarily
by transient caribou.occasionally they spent time in the
area,particularly in spring in snow-free areas.Skoog
(1968)felt that the thick spruce and wet conditions found
in the area would not normally attract caribou although they
did feed somewhat during migration across the area.The
area lost would be <1%of the total Nelchina range and is
generally considered low-quality habitat.The exception to
this is the Denali access road running from the Denali
Highway south to the Watana dam site.This road would
traverse an area utilized by members of the upper Susitna-
Nenana subherd during the entire year.Historically this
area was used by the main Nelchina herd during both summer
and winter and was considered by Skoog (1968)in terms of
year-round use to have been the most important region in the
Nelchina range.Although during the past 10 years few main
herd animals have utilized this area it is expected that
heavy use will again occur sometime in the future.
Harassment or disturbance of Nelchina caribou caused by
increased aircraft traffic associated with the proj ect as
well as vehicular traffic along the access roads and heavy
equipment in the borrow sites and the dam construction sites
is certain to occur in portions of the development area
although the area along the Denali access road is the only
area with a history of heavy caribou use.contradictory
conClusions on the impacts of disturbance on caribou have
been reported.Calef et al.(1976)reported that severe
harassment could cause injury or death,increased energy
expenditure and reduced condition,and abandonment or
reduced use of traditional ranges.Miller and Gunn (1979)
felt that helicopter harassment had the potential for
causing stress in Peary caribou,leading to additional
47
mortality.Davis and Valkenburg (1984)reported that the
Del ta caribou herd has been exposed to more disturbance
(including considerable civilian and military aircraft
traffic)than any other Alaskan caribou herd,yet has grown
at a rapid rate and is now larger than ever recorded.
Bergerud et ale (1984b)felt that the available data
indicated caribou could tolerate periodic severe disturbance
without adverse effects on productivity and survival.
Shideler (1986)concluded'from his literature review that
caribou were probably most sensitive to harassment during
calving and post-calving and that large groups were more
reactive than small groups.He also felt that caribou could
adapt to some levels of harassment if no negative
experiences such as hunting were associated with the
disturbance.Despite the lack of conclusive evidence on
impacts of harassment on individual caribou and on caribou
populations it does seem prudent to minimize disturbance
when possible,particularly on the calving grounds (Bergerud
1978)and during post-calving.In regard to the Susitna
project the two key points appear to be restriction of
activities such as low-level aircraft traffic on the
Talkeetna Mountains calving grounds during calving and post-
calving and close monitoring of possible harassment in the
vicinity of the Denali access road which is used during
calving by animals from the upper Susitna-Nenana subherd.
Developments and associated human activity may reduce the
amount of habitat available t:o caribou by causing direct
avoidance of areas nearby developments and by impeding
movements of animals between segments of their range.It
was concluded,based on the sex and age composition of
caribou sampled along the Trans-Alaska pipeline haul road
compared with region-wide surveys and based on the
relocations of collared caribou,that the cow-calf segment
of the Central Arctic herd tended to avoid the pipeline
corridor and haul road (Cameron et ale 1979,Whitten and
Cameron 1983).Carruthers et al.(1984)maintained,that
these conclusions were erroneous because the differences in
composition were the result of differential habitat
selectivity rather than avoidance of the corridor.Shideler
(1986)found that a reanalysis of Carruthers et ale (1984)
data supported the conclusion that the cow-calf segment
avoided the pipeline corridor.Horejsi (1981)reported that
caribou showed signs of anxiety and fear in the presence of
fast-moving vehicles;they reacted strenuously trying to
escape.Johnson and Todd (1977)concluded that a group of
mountain caribou became habituated to a highway and traffic
and continued to use a traditional movement route despite
harassment and mortality.Klein (1971)reported that well-
traveled highways and railroads have obstructed the
movements of wild reindeer in Norway.Bergerud et al.
(1984b)failed to find strong correlations between the
construction of roads through caribou ranges and population
decl ines except when the roads were used as access routes
48
for hunters,resulting in overharvests.Despite these
contradictory findings on the impacts of highways on the
free movement and behavior of caribou it does appear that
high levels of activity along highways may affect caribou
in certain situations (Klein 1971,Horejsi 1981,Smith and
Cameron 1983).
Nelchina caribou cross the Richardson Highway,often in
large numbers,and have done so during many years since
about 1960 (Hemming 1971).The Richardson crossings take
place in timbered habitat in contrast to the open tundra and
shrublands of the proposed Denali access route.Nelchina
caribou also cross the Glenn Highway (primarily the Tok-
Cutoff),Denali Highway,Lake Louise Road and Nabesna Road
on occasion.The Glenn Highway and Nabesna Road are crossed
twice yearly during those years (perhaps half of recent
years)when the Nelchina herd winters in the Wrangell
Mountains-Mentasta Mountains area.Small numbers of
caribou,primarily bulls,cross the Glenn Highway west of
Glennallen during winter and spring each year.In some
years small numbers of caribou cross the Lake Louise Road
during the autumn dispersal period and in winter.
It is not clear how the Denali access road and associated
traffic will impact caribou migrating from the Chulitna
Mountains to and from winter range to the east.It is
likely that small amounts of habitat directly adjacent to
the road will receive less use than prior to project
construction.Based on the reactions of Nelchina caribou to
highways in other portions of their range it is reasonable
to expect that the east-west 'migrations from the Chulitna
Mountains would continue to occur,although the open terrain
found along the Denali route could cause caribou to react
differently.
other developments associated with the Susitna project,such
as settlements,borrow areas and transmission lines would
not be located in important caribou habitats and are not
expected to cause serious impacts.
Disruption of movements,should they occur,would most
likely be caused by the Watana impoundment and the Denali
.access road.The Watana impoundment would intersect a
heavily used historical migration route between summer and
winter range in the Chulitna Mountains and benchlands to the
east and the calving grounds and summer range in the
Talkeetna Mountains.According to Skoog (1968),Hemming
(1971)and Pegau and Bos (1972)large numbers of caribou
crossed the Susitna River,mainly between Deadman and Jay
Creeks,during most years between 1951 and 1972.Deeply
worn caribou trails are still visible in this area although
the last large movement of caribou through this migratory
corridor was about 1976.Several of the radio-collared
caribou crossed the Susitna in this region during the.study;
caribou occurred.It
caribou will again at
important winter and
thereby crossing the
..
49
however,no large-scale crossings of
seems highly probable that Nelchina
some point utilize the historically
summer range north of the Susitna,
proposed impoundment area .
During some years of this study large numbers of caribou
utilized the upper portion of the'proposed Watana
impoundment during spring migration from eastern winter
ranges to the calving grounds.Skoog (1968)mentioned that
caribou used the frozen Susitna River as an avenue for
travel and this was observed during the spring of 1981 when
many caribou traveled on the ice of the Susitna between the
confluences of the Oshetna River and Kosina Creek.Creation
of the impoundment would limit options of caribou migrating
through the area.
It is unclear how caribou would react to the presence of a
large reservoir in the path of a traditional migratory
corridor.Refusal to cross the reservoir would extend the
distance traveled between the calving grounds and summer and
winter range north of the impoundment by perhaps 60 miles.
This might be particularly important during the spring
migration to the calving grounds when pregnant females are
in the poorest condition of the year.If the reservoir were
a barrier to free movement it could result in reduced use of
the northwestern portion of the Nelchina range,thereby
reducing the long-term carrying capacity.
The Denali access road,as previously mentioned,intersects
the migratory route of about 50%of the upper Susitna-Nenana
subherd between calv ing and summer range in the Chul i tna
Mountains and winter range to the east.In addition,bulls
from the main Nelchina herd use the Chulitna Mountains as
summer range,thereby crossing the proposed access road.
Historically,large numbers of main Nelchina herd caribou
summered and wintered in the area of the Denali access
route.It is not known how caribou would react to the
access road and associated tra'ffic;however,based on
observations at other highway crossing sites within the
Nelchina range and observations in other areas (Shideler
1986)it seems likely that unless heavy traffic is
encountered caribou will successfully cross the road.Most
crossing would likely occur during May,June,September and
October and if problems with deflections were noted some
system of traffic control such as periodic convoys could be
instituted.
Neither the Richardson Highway nor the adjacent TranS-Alaska
oil pipeline corridor appear to have had serious negative
impacts on the Nelchina caribou herd (Eide et ala 1986).
Caribou continue to cross these structures during migrations
to and from winter range and the herd has been growing since
about 1972.
------------_.._---------~-------~----------
50
Increased mortality resulting from various aspects of
project construction could impact population dynamics of the
main Nelchina herd and the upper Susitna-Nenana subherd.
The greatest potential mortality factor is attempted
crossings of the Watana impoundment under hazardous
conditions.Large-scale historical crossings occurred
primarily during April and Mayas caribou were en route to·
the Talkeetna Mountains calving grounds and during June and
July as they moved to summer range north of the Susitna.
The summer crossings,with a minimum distance of 0.75 mi,
would occur during an open water period.Caribou are known
to be strong swimmers.Skoog (1968)saw a band cross Lake
Louise,a distance of about 5 mi.He also stated that
caribou commonly crossed much larger lakes in Canada.
Crossings during this period would not appear to pose a
great hazard except perhaps to young calves,and Skoog
(1968)noted that caribou take readily to water at an early
age.During spring crossings conditions could be much more
hazardous and females would be in the poorest condition of
their annual cycle.This would be a period of transition
from an ice-covered reservoir at low water levels to a
rapidly filling open water impoundment.Potential hazards
could include ice-covered shores,ice sheets,ice blocks and
steep ice ramps formed by winter "drawdown"of the reservoir
(Hanscom and Osterkamp 1980).Skoog (1968)mentioned
several instances of injuries resulting from falls on or
through ice.Both Klein (1971)and Vilmo (1975)mention ice
shelving as a mortality factor of reindeer on reservoirs in
Scandinavia.If crossing were attempted during the period
of reservoir breakUp and ice floes were stacked along the
southern shore by a northerly wind,mortalities might result
from animals being unable to exit the water.
During autumn dispersal,low to moderate rates of crossings
in the Watana impoundment area have taken place during the
past 5 years.Rather than large-scale migrations,movements
during this period appear to be of a wandering nature.
Impoundment crossings during this period would probably be
relatively nonhazardous.Relatively few animals crossed
during the rut and winter periods.·Neither time appears to
pose a serious threat because of probable reservoir
conditions and the numbers of animals involved.The
transitory phase of freeze-up might present increased
hazards because of thin ice but would probably be similar to
conditions already occurring on large lakes.
There are indications that migratory mammals will,·on
occasion,attempt to follow traditional routes even after
changes have occurred which--make them hazardous.Near
Vail,Colorado mule deer (Odocoileus hemionus)fell from a
precipice created by highway construction across migratory
trails (Reed et al.1979).Possibly more than 10,000
caribou from the George River herd were killed while
..
51
attempting-to cross a river at flood stage during fall
migration (Sullivan 1984 1 Goddard 1985).Mass drownings of
elk (Cervus canadensis)(including about 60 animals in 1978,
which were thought to have resulted from breaking through
thin ice created by drawdown)have been reported from the
Blue Mesa Reservoir in Colorado (Harza-Ebasco 1985).These
animals were thought to have been following a traditional
migration route.The Lucky Peak Reservoir in Idaho is on a
number of mule deer migratory routes and during the early
years following construction up to about 175 animals were
lost annually..Losses were caused by falling on the ice,
breaking through the ice and drowning 1 being unable to exit
the reservoir on the opposite shore due to ice sheets on the
reservoir banks,and becoming mired in the mud around the
reservoir perimeter (Harza-Ebasco 1985).
It appears to me that the potential 1 under specific
conditions 1 would exist at the Watana site for serious
levels of mortality of females migrating to the Talkeetna
Mountains calving grounds.The main Nelchina herd would
need to resume use of historical winter range north of the
Susitna River;this is likely to occur at some point.The
spring migration to the calving grounds would need to
coincide with hazardous ice conditions on the reservoir.
Both of these events would likely occur during the first two
weeks in May.The female segment of the herd would need to
attempt a reservoir crossing rather than extend their
migration around the reservoir.This might well occur as
this is a traditional route and females would be "motivated"
to reach the calving grounds.
Some mortality of caribou from collisions with vehicles
along the Denali access road may occur;although it is not
expected to be a serious problem.Caribou-vehicle
collisions along the Richardson Highway,where maj or
crossings occur,probably do not result in more than about
50 deaths per year (Tobey 1 pers.comm.).Vehicle-caribou
collisions are reportedly uncommon along the Dalton Highway
(Cameron,pers.comm.).
Increased hunter access would be provided by the Denali
.access road and the impoundments.This could result in
increased harvest,particularly on the upper Susitna-Nenana
subherd.Reductions in·numbers of permits issued or area
hunting restrictions could become necessary in order to
prevent a local overharvest of resident subherd animals.
Illegal kills could increase with additional access into
remote areas.
Robey (1978)suspected that wolves used roads to their
advantage when hunting caribou;this behavior might increase
predation along the Denali access road.However 1 the Denali
access road would also provide increased access for trapping
52
and hunting of wolves and bears which are predators on
caribou.~
Increased human access to important caribou habitats
including the calving grounds and summer range in the
northeastern Talkeetna Mountains,would likely be provided
by project construction.This is currently one of the most
remote and inaccessible regions wi thin the Nelchina range
and must be considered the most important single geographic
area for the Nelchina herd.The Denali access road would
provide access to important caribou habitat currently
utilized primarily by the upper Susitna-Nenana subherd and
historically important to the main Nelchina herd.While it
is difficult to envision development occurring in these
areas to the extent that caribou use would be impacted such
as·has occurred on the Prudhoe Bay oilfields,the
possibility must be considered.
Shideler (1986)discussed two case histories in which linear
developments appeared to disrupt and modify traditional
migration patterns of wild reindeer;those of the Taimyr
herd in the Soviet union and the Snohetta herd in southern
Norway.A pipel ine-railroad-highway corridor within the
range of the Taimyr herd disrupted movements and caused
abandonment of a portion of the range,resulting in overuse
of other areas.Mortalities resulted from train collisions
and deflections into a river.Despite these factors the
herd has continued to increase.Hydroelectric development
and a transportation corridor acted as "semibarriers"to
movements between seasonal habitats for the Snohetta herd.
These developments and associated human activities caused
avoidance of some areas and disruption of traditional
migration routes.Range overuse developed and population
impacts were noted;i.e.,small body size,reduced
reproduction and starvation.
Studies of the effects of the Upper Salmon Hydroelectric
Development on the Grey River caribou herd in Newfoundland
found that many animals avoided the development area during
construction and that animals that migrated through the area
during construction had their movements disrupted (Northcott
1984).However caribou numbers returned to preconstruction
levels after the development was completed.Displacement
and disrupted movements observed during construction had no
measurable effect on herd productivity.
Impacts studies (simpson 1986)were conducted on a small
group of woodland caribou which periodically crossed,and
seasonally used,river bottom habitat which was flooded by
an impoundment on the Columbia River north of Revelstoke,
British Columbia.This study was conducted for three years
prior to flooding,and thus far,one year post-flooding.
53
Riparian meadow habitats which were used extensively during
May and which were thought to be important for predator
avoidance as wei 1 asprovid-ing~-a·bundant·---fcrod,··""Were--l-o·st··
after flooding.Caribou continued to cross the impoundment
after flooding and no mortality was noted.However,
crossings,both historically and after flooding,occurred
during ice-free periods with minimal hazards.Mortalities
of both moose and deer which tried to cross the ice-covered
reservoir were noted.A decline in caribou calf recruitment
was documented during the first year after flooding;
however,a causal relationship was not established.
Cumulative habitat loss and degradation is probably the most
serious concern of the Susitna hydroelectric project rather
than any immediate,severe impacts.The proposed
hydroelectric project is only one (although the major one)
of a number of developments which have occurred or may
occur,on the Nelchina range.Considerable mining activity
already is taking place,particularly in the eastern
Talkeetna Mountains and Clearwater Mountains.A state oil
and gas sale is planned for the Lake Louise Flat,a major
wintering area.The Bureau of Land Management plans to open
much of the Nelchina Basin to oil exploration.Considerable
land is passing from pUblic to private ownership through the
Alaska Native Claims Settlement Act and through state land
disposal programs.Agricultural enterprises have been
attempted.While no single action may have a catastrophic
impact it seems likely that long-term cumulative impacts
will result in a lessened ability of the Nelchina range to
support large numbers of caribou.Habitat destruction,
increased access,development,increased human activities,
disturbance and barriers to free movement will all probably
contribute to this loss.
ACKNOWLEDGEMENTS
sterling Eide and Karl Schneider initially conceived and
designed tllis study.Karl supervised the stUdy and was
particularly effective in administering the contract,
thereby allowing me to utilize my time effectively on the
project.Many members of the Alaska Department of Fish and
Game assisted.me in the field:Paul Arneson,Warren Ballard,
Don Cornelius,Jim Dau,Sterling Eide,Craig Gardner,Enid
Goodwin,Polly·Hessing,Patsy Martin,Dennis McAllister,
Mike McDonald,sterling Miller,Ron Modafferi,Bill Taylor,
Bob Tobey,John Westlund and Jack Whitman.Particular
thanks go to Jim Lieb who flew many of the radio-tracking
surveys.Expertise in data management and data analysis was
provided by Danny Anctil,Larry Aumiller,SuzAnne Miller,
Tammy otto and Becky Strauch.Project aircraft pilots
included:Ken Bunch,Don Deering,Lynn Ellis,Al Lee,Craig
Lofstedt,Vern Lofstedt,Chuck McMahon and Harley McMahon.
I appreciate the contributions·made by each of these
individuals.
54
REFERENCES
Ballard,W.B.,R.o.Stephenson and T.H.Spraker.1981.
Nelchina Basin wolf studies.Alaska Dept.Fish and
Game,Juneau.201pp.
Bergerud,A.T.1978.Caribou.Pages 83-101 in J.L.
Schmidt and D.L.Gilbert,eds.Big Game of North
America (Ecology and Management).Stackpole Books,
Harrisburg,Pa.
1980.A review of the popUlation dynamics of
caribou and'wild reindeer in North America.Pages 556-
581 in E.Reimers,E.Gaare,and S.Skjenneberg,eds.
Reindeer/Caribou Symposium II,Roros.Norway.
1983.The natural population control of caribou.
Pages 14-61 in F.L.Bunnell,D.S.Eastman,and J.M.
Peek,eds.Symposium on natural regulation of wildlife
populations.Univ .Idaho For.Wildl.and Range Exp.
Stn.
,H.E.Butler,and D.R.Miller.1984a.---~Antipredator tactics of calving caribou:dispersion in
mountains.Can.J.Zool.62:1566-1575.
,R.D.Jakimchuk,and D.R.Carruthers.1984b.The-......,.---:-bUffalo of the north:caribou (Rangifer"tarandus)and
human developments.Arctic 37:7-22.
Bos,G.N.1973.Nelchina caribou report.Alaska Dept.
Fish and Game,Juneau.25pp.
1974.Nelchina and Mentasta caribou reports.
Alaska Dept.Fish and Game,Juneau.34pp.
1975.A partial analysis of the current population
status of the Nelchina caribou herd.Proc.Int.
Reindeer and Caribou Symp.1:170-1&0.
Calef,G.W.,E.A.DeBock,and G.M.Lortie.1976.The
reaction of barren-ground caribOU to aircraft.Arctic
29:201:212.
Cameron,R.D.,K.R.Whitten,W.T.Smith,and D.D.Robey.
1979.Caribou distribution and group composition
associated wi th construction of the Trans-Alaska
Pipeline.Canadian Field Naturalist 93:155-162.
';#-
55
Carruthers,D.R.,R.D.Jakimchuk,and S.H.Ferguson.
1984.The relationship between the Central Arctic
caribou herd and the Trans-Alaska··pipeTine.Rept.to
Alyeska Pipeline Servo Co.by Renewable Resources
Consulting Services,Ltd.,Sidney,B.C.207pp.
Davis,J.L.,P.Valkenburg,and S.J.Harbo,Jr.1979.
Refinement of the aerial photo-direct count-
extrapolation caribou census technique.Alaska Dept.
Fish and Game,Juneau.23pp.
______,and P.Valkenburg.1984.Demography of the Delta
caribou herd under varying rates of natural mortality
and harvest by humans.Alaska Dept.Fish and Game,
Juneau.55pp.
Doerr,J.1979.Population analysis and modeling of the
western Arctic caribou herd with comparisons to other
Alaskan Rangifer populations.M.S.Thesis,Univ.
Alaska Fairbanks.340pp.
Eide,S.H.1980.Caribou survey-inventory progress report.
Pages 31-34 in R.A.Hinman,ed.Annual report of
survey-inventory activities.Alaska Dept.Fish and
Game,Juneau.
_____,S.D.Miller,and M.A.Chihuly.1986.oil
pipeline crossing sites utilized in winter by moose and
caribou in southcentral Alaska.Canadian Field-
Naturalist.100:197-207.
FUller,T.K.and L.B.Keith.1981.Woodland caribou
population dynamics in northeastern Alberta.J.Wildl.
Manage.45:197-213.
Glenn,L.P.1967.Caribou report.Alaska Dept.Fish and
Game,Juneau.36pp.
Goddard,J.1985.The incident at Limestone Falls.
Harrowsmith No.58,Vol.IX:4:25-38.
Hanscom,J.T.,and T."E.Osterkamp.1980.Potential
caribou-ice problems in the Watana reservoir,Susitna
hydroelectric project.The Northern Engineer 12:4-8.
Harza-Ebasco susitna Joint Venture.1985.Survey of
experience in operating hydroelectric projects in cold
regions.Alaska Power Authority Processed Report.Vol.
2.Appendix C.
Hemming,J.E.1971.The distribution and movement
patterns of caribou in Alaska.Alaska Dept.Fish and
Game,wildl.Tech.Bull.No.1.60pp.
56
1975.Population growth and movement patterns of
the Nelchina caribou herd.Pages 162-169 In J.R.
Luick,P.C.Lent,D.R.Klein,and R.·G.White,eds.
Proc.First International Reindeer and Caribou
symposium.Biological Papers of the University of
Alaska.Special Report 1.551pp.
,and L.P.Glenn.1969.Caribou report.Alaska----=Dept.Fish and Game,Juneau.37pp.
Horejsi,B.L.1981.Behavioral responses of barren ground
caribou to a moving vehicle.Arctic 34:180-185.
Johnson,D.R.,and M.C.Todd.
highway crossing by mountain
Field Naturalist 91:312-314.
1977.Summer use of a
caribou.The Canadian
Klein,D.R.1971-
and disturbances.
Reaction of reindeer to obstructions
Science 173:393-398.
Lentfer,J.1965.Caribou report.
Game,Juneau.20pp.
Alaska Dept.Fish and
McGowan,T.A.1966.Caribou report.
and Game,Juneau.19pp.
Alaska Dept.Fish
Miller,S.,and D.Anctil.1981.Biometrics and data
processing.Susitna Hydroelectric Project Annual
Progress Report.Alaska Dept.Fish and Game,Juneau.
15pp.
Miller,F.L.,and A.Gunn.1979.Responses of PearY
caribou and muskoxen to helicopter harassment.
Canadian Wildlife Service Occasional Paper No.40.
90pp.
Northcott,P.L.1984.Impact of the Upper Salmon
Hydroelectric Development on the Grey River caribou
herd.Second North American Caribou Workshop,17-20
October 1984,Montreal,Quebec.
Pegau,R.E.,and G.N.Bos.1972.Caribou report.Alaska
Dept.Fish and Game,Juneau.32pp.
___-='and J.E.Hemming.1972.Caribou report.Alaska
Dept.Fish and Game,Juneau,221pp.
Pitcher,K.W.1984.Susitna hydroelectric project 1983
annual report ~volume IV caribou.Alaska Dept.Fish
and Game,Juneau.43pp.
1985.Susitna hydroelectric project 1984 annual
report;caribou.Alaska Dept.Fish and Game,Juneau.
44pp.
-.
57
Rausch,R.A.1967.Some aspects of the population ecology
of wolves;Alaska.Am.ZooL 7:253';;"265:------_._....
1969.A summary of wolf studies in southcentral
Alaska,1957-1968.Trans.North Am.Wildl.and Nat.
Resour.Conf.34:117-131.
Reed,D.F.,K.R.Kincaid,and T.
Migratory mule deer fall from
Wildl.Manage.28:272.
D.I.
highway
Beck.1979.
cliffs.J.
Robey,D. D.1978.Behavioral patterns of barren-ground
caribou of the Central Arctic herd adjacent to the
Trans-Alaska oil pipeline.M.Sc.Thesis,Univ.Alaska
Fairbanks.199pp.
Shideler,R.T.1986.Impacts of human developments and
land use on caribou:a literature review.Volume II.
impacts of oil and gas development on the Central
Arctic herd.Alaska Dept.Fish and Game,Habitat
Division,Juneau.Technical Report No.86-3.127pp.
Simpson,K.1986.Impacts of a hydro-electric reservoir on
populations of caribou and grizZly bear in southern
British Columbia.Processed report prepared by
Keystone Bio-Research Box 2896,Revelstoke,B.C.for
the B.C.Ministry of Environment,Nelson,B.C.40pp.
Siniff,D.B.,and R.O.Skoog.1964.Aerial censusing of
caribou using stratified random sampling.J.Wildl.
Manage.28:391-401.
Skoog,R.O.1968.Ecology of the caribou (Rangifer
tarandus granti)in Alaska.Ph.D.Thesis,Univ.
California,Berkeley.699pp.
Smith,W.T.,and R.D.Cameron.·1983.Responses of
caribou to industrial development on Alaska's Arctic
slope.Acta Zool.Fennica 175:43-45.
Sullivan,R.1984.The torrent-of death.
Illustrated 16 (18):100-114.
Sports
Trent,T.T.,and 0 .J.Rongstad.1974 .Home range and
survival of cottontail rabbits in southwestern
Wisconsin.J.Wildl.Manage.38:459-471.
Van Ballenberghe,V.1985.Wolf predation on caribou:the
Nelchina herd case history.J.Wildl.Manage.49:711-
720.-
'i4_'~'kt__...~~....-......---------------------
Viereck,L.A.,and C.T.Dyrness.1980.A preliminary
classification system for vegetation of Alaska.U.S.
Forest Service General Technical Report PNW-106.38pp.
Vilmo,L.1975.The Scandinavian viewpoint.Pages 4-9 in
J.R.Luick et al.,ed.Proceedings of the First
International Reindeer and Caribou Symposium.
Biological Papers of the university of Alaska Special
Report No.1.
58
"
~
"'
~'"
Watson,G.W.,and R.F.Scott.
the Nelchina caribou herd.
Conf.214:499-510.
1956.Aerial censusing of
Trans.N.Amer.Wildl.
whitten,K.R.,and R.C.Cameron.1983.Movements of
collared caribou,Rangifer tarandus,in relation to
petroleum development on the Arctic slope of Alaska.
Canadian Field Naturalist 97:143-146.
•.~l/i!>
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59
PERSONAL COMMUNICATIONS
Raymond Cameron,Alaska'Department of Fish and Game,
Research Biologist,,26 November 1984.
Sterling Eide,Alaska Department of Fish and Game,Regional
Supervisor,21 November 1984.
Ronald Modafferi,Alaska Department of Fish and Game,
Research Biologist,25 March 1986.
Robert Tobey,Alaska Department of Fish and Game,Area
~anagement Biologist,21 November 1984 .