HomeMy WebLinkAboutAPA407SUSITNA HYDROELECTRIC PROJECT
PHASE II PROGRESS REPORT
i
I
.,..
.I i
!
r-
I
BIG GAME STUDIES
Volume II MOOSE -DOWNSTREAM
Ronald D.Modafferi
ALASKA DEPARTMENT OF FISH AND GAME
Submitted to the Alaska Power Authority
April 1983
G-04j 9
;
..J
oj
1,
.".piii,
SUSITNA HYDROELECTRIC PROJECT
BIG GAME STUDIES
PHASE I I -PROGRESS REPORT
VOLUME I I.MOOSE -DOWNSTREAM
Ronald D.Modafferi
ALASKA DEPARTMENT OF FISH AND GAME
Submi tted to the Alaska Power Authority
April,1983
ARLIS
Alaska ResQurces
Library &Information Services
Anchorage,Alaska
TK
lif~5
o~~",f'
8r:v
no,lf o7
-~~--_._'----_._-_:""-_""";"'_"""""'----""--
-
PREFACE
In early 1980,the Alaska Department of Fish and Game contracted
with the Alaska Power Authority to collect information useful in
assessing the impacts of the proposed Susitna Hydroelectric
Project on moose,caribou,wolf,wolverine,black bear,brown
bear and Dall sheep.
The studies were broken into phases which conformed to the
anticipated-licensing schedule.Phase I studies,January I,1980
to June 3D,1982,were intended to provide information needed to
support a FERC license application.This included general
studies of wildlife populations to determine how each species
used the area and identify potential impact mechanisms.Phase II
studies continued to provide additional information during the
anticipated 2 to 3 year period between application and final FERC
approval of the license.Belukha whales were added to the
species being studied.During Phase I I,we are narrowing the
focus of our studies to evaluate specific impact mechanii?ms,
quantify impacts and evaluate mi tigation measures.
This is the first annual report of ongoing Phase II studies.In
some cases,objectives of Phase I were continued to provide a
more complete data base.Therefore,this report is not intended
as a complete assessment of the impacts of the Susi tna Hydro-
electric Project on the selected wildlife species.
The information and conclusions contained in these reports are
incomplete and preliminary in nature and subject to change with
further study.Therefore,information contained in these reports
is not to be quoted or used in any publication without the
wri tten permi ssion of the authors.
The reports are organized into the following 9 volumes:
,
r
--
Volume I.
Volume I I.
Volume I I I.
Volume IV.
Volume V.
Volume VI.
Volume VI I.
Volume VI I I.
Volume IX.
Big Game Summary Report
Moose -Downstream
Moose -Upstream
Caribou
Wolf
Black Bear and Brown Bear
Wolverine
Dall Sheep
Belukha Whale
ARLIS
Alaska ReS(lUrCes
Library &Information Services.
Anchorage,Alaska
ii
SUOOf1ARY
Recent demand for non-fossil fuel energy has stimulated public
interest and initiated the formulation of a proposal to develop
the hydroelectric potential of the Susitna River.The proposal
is founded on construction of two water impoundments,an earth/
rock filled dam at a site between Tsusena and Deadman Creeks and
a concrete'arch dam at Devil Canyon,each with electric gener-
ating facilities,and together capable of about 1200 Mw of cap-
acity.
Feasibility of the proposed project will be determined in part by
evaluating environmental impacts as well as the economic,base.
Environmental impacts can be divided into 2 hydrological cate-
gories:1)pre-impoundment"those impacts occurring in areas
upstream from the impoundments and 2)post-impoundment,those
impacts occurring in areas downstream from the impoundments.
Pre-impoundment impacts will primarily involve immediate loss of
habitats through inundation.Post-impoundment impacts will pro-
bably involve gradual and less dramatic changes in riparian en-
vironments through altered flow regimes and altered characteris-
tics of the water itself and alterations in other environmental
features.Such environmental effects may affect wildlife direc-
tly through hydrologic conditions and/or be mediated indirectly
through several intermediate environmental components.
iii
~,
-.
,"""
Irrespective of the nature of the cause,the ultimate impacts of
indirect effects or direct effects on migratory species of wild-
life may be realized at distances quite removed from their proxi-
mate cause.
In its 215.km course from Devil-Canyon to Cook Inlet,the Susitna
River is an outstanding component of a very productive watershed.
Perhaps the innate value of the lower Susi tna River Valley as
wintering habitat for moose is unsurpassed elsewhere in the
State.
Objectives of this study were to determine the probable nature
and approximate magnitude of impacts of the proposed Susi tna
River hydroelectric project on moose (Alees alees gigas Miller)
in areas along the Susitna River downstream from the prospective
Devil Canyon dam site to Cook Inlet.To accomplish this objec-
tive one must thoroughly understand how moose depend on flood-
plain habitats along the Susitna River.Only then,will one be
able to assess the relative importance of various floodplain
characteristics to moose and integrate those findings with hypo-
thetical post-project conditions to fully evaluate project
impacts on subpopulations of moose.This report is primarily
based on data gathered between 15 October 1982 and-15 October
1983 but also include~pertinent findings from the Phase I study
final report (Modafferi 1982).
Data on patterns of movement,habitat use,productivity,survival
and identity of subpopulations for moose ecologically affiliated
iv
with the Susitna River were primarily synthesized from 2178 radio
relocations obtained from samples of la,29 and 18 moose captured
and radio-collared on 17 April 1980,10-12 March 1981 and 24
February to 10 March 1982,respectively,in floodplain habitats
along the Susitna River between Devil Canyon and Cook Inlet and
subsequently radio-relocated through 15 October 1982.
Radio-collared moose,were relbcated at about biweekly intervals
through 16 March 1981 and about la-day intervals from that time
through 15 October 1982.This schedule provided 7,la,12,7,7
relocation sites for most individuals monitored during the winter
(1 January thru 28 February),calving (10 May thru 17 June),sum-
'mer (1 July thru 31 August),"hunting season"(1 September thru
30 September)and breeding (14 September thru 15 October)per-
iods,respectively,Most data collected from radio-collared
moose were analyzed relative to these periods in the life history
of moose,Effects of sex,subpopulation and year factors vlere
considered in interpretive analyses,Radio-relocations dated
outside of these periods were grouped within spring,summer,
autumn and post-breeding transi tory intervals,'
To assess magnitude of seasonal and regional moose use of flood-
plain habitats along the Susitna River from Cook Inlet to Devil
Canyon,radio-relocation data were integrated with information
collected on 6 and 7 aerial censuses for moose conducted between
9 December 1981 and 12 April 1982 and between 29 October 1982 and
22 February 1983,respectively.
v
-
-
-
-
-
,~
-
.....
Data from river censuses,irl turn pfovided additional and inde-
pendent information on productivity/survival of moose which
winter in Susitna River floodplain habitats.In these interpre-
tive analyses,sex,seasonal pe~iod and subpopulation categories
were considered.
Preliminary findings from radio-collared samples exhibited gros-
sly different patterns of behavior and geographically discrete
breeding areas for three groups of moose and resulted in subpopu-
lation classifications for individuals with breeding ranges
centered in areas:1)to the north of Talkeetna,2)to the south
of Talkeetna and on the eastside of the Susitna River and 3)to
the south of Talkeetna and not in eastside areas.Observations
of movement patterns from a more recently radio-collared sample
of moose suggest that two other discrete subpopulations of moose
which frequent:1)the Little Susi tna Ri ver/v{asi lla area or the
Mt.Susi tna/Beluga Lake area at other seasonal periods,also
winter in Susi tna River floodplain habi tats .
Some individual moose were found to range mostly within Susitna
River floodplain habitats,other individual moose only used those
habi tats during the winter and/or more frequently during the
calving period,and other moose used floodplain habitats during
one of those periods and also traversed riparian areas when
moving from one range to another.Though most radio-collared
.-
I
moose used the Susitna River primarily as a winter range between
January through l'.pril,about 16 percent of the radio-collared
vi
moose frequented floodplain habitats in extensively islanded
areas throughout the year.For the second consecutive year of
study,radio-collared female moose north of Talkeetna sought
island and riparian habitats along the Susi tna River·near the
time of calving.The later movement pattern was attributable to
availabi li ty of nutri tous food and/or avoidance of predators.
Radio-collared moose north of Talkeetna seldom ranged farther
than 8 km from riparian habi tats;moose south of Talkeetna com-
monly ranged farther than 8 km from the Susitna River and reloca-
tions up to 40 km from floodplain areas were not uncommon for the
later area.Though moose north of Talkeetna did not range far
from riparian habitats,some did travel greater distances,paral-
lel to the river,during each annual cycle.
Large variation between individuals and sexes wi thin years and
within individuals and sexes between years was observed in move-
ments and sizes of ranges for radio-collared moose.Males gener-
ally ranged over greater distances than females.Many individual
moose were found to range over larger areas during the second
year of study.Similar but smaller increases in range size were
observed after 2 years of study.
Most radio-collared moose returned to floodplain habi tats each
winter but moose of each sex were not known to return in consecu-
tive years and one male did not return to Susitna River riparian
habi tats for two consecutive winter periods.
vii
-
...,.
-
~\
-
Since magnitude of use of winter range by Susi tna River Valley
subpopulations of moose is partly related to severity of climatic
conditions,findings presented in this report must be considered
as preliminary since sampling occurred and data wer~accumulated
during the relatively mild or average winters between 1979 and
1983.The later ...linter,which was characterized by.large amounts
of snowfall·through December and was subsequently followed by
mild conditions and recession of snowcover provided some informa-
tion on weather related variations in behavior of moose and sub-
stantiated importance.of this concern.
In the winter of 1981-82,a maximum of 369 moose were observed in
6 censuses of floodplain habitats along the Susitna River between
Cook Inlet and Devil Canyon.A maximum of 934 moose were
observed in 7 similar censuses conducted in the winter of
1982-83.For the later winter,densities of moose greater than
four per km 2 of surface area were calculated for moose occupying
floodplain habitats between the Yentna River and Cook Inlet in
late December.Overall observations indicated unequal distribu-
tion of moose wi thin and between four geographic zones of the
Susitna River.Within and between year variation in moose use of
floodplain habitats were assoc·iated with winter weather condi-
tions.
viii
riIovements and distribution of radio-collared moose during spe-
cific life history periods were analyzed and discussed in rela-
tion to potential impacts of hydrologic development and mi tiga-
tion options.These data substanti ated that impacts to moose
which occur wi thin Susi tna River floodplain habitats may ul ti-
mately be realized at great distances from the Susitna River and
that each subpopulation of moose may be vulnerable to different
types of -impacts.Similarly,mitigation measures need not be
limi ted to floodplain areas to be affective but may have to be
specific for a particular subpopulation of moose.
Ninety-seven percent of the radio-collared female moose were
known to produce young in 1982;of them 59 percent produced
twins.Calf production in 1982 appeared greater than in 1981
after parturition,but by November ratios of calves per female
were similar for both years.Early winter weather conditions
were more severe in 1982 than in 1981 and may account for the
decrease in calf survival observed in 1982.
Effort expended to hunt moose,and numbers of moose killed by
hunters indicate that moose in subunits 14B and 16A provide
recreational opportunity,and sustenance for large numbers of
participants,many of which are from urban areas.Subpopulations
of moose in areas along the Susitna River north of Talkeetna pro-
vide for significantly fewer people than subpopulations in the
aforementioned subunits but in this subunit most users are pro-
bably local residents.
ix
--
-
-
-
-
-
Mortali ty of moose recorded during the study was attributed to
hunting (on male and female moose),accidents associated with the
Susitna River such as slipping on ice,drowning,perhaps on ice
or log jams during high water,and predation by brown bears.
Data indicated that males sustained higher rates of hunting mor-.
tali ty and females experienced higher rates of non-hunting mor-
tality.
Moose winter use of sites where vegetative associations have been
al tered to more seral communi ties by activi ties of humans was
documented.During the winters of 1981-82 and 1982-83,it was
not uncommon to observe 40-60 moose in each of several sub-climax
si tes about 3 km 2 in size.
Because of the potential for habitat rehabilitation as a mitiga-
tion option,it was recommended that research studies designed to
more fully understand the interrelationships between rehabili-
tated habitat and ecology of moose in the lower Susi tna River
Valley be initiated.
Limi tations of sampling methods and present samples and their
relationship to differential behavior and winter weather condi-
tions were discussed.It was proposed that more radio-collared
moose,particularly males,need to be studied north of Talkeetna.
It was also suggested additional males be radio"'"collared and
monitored in other areas further downstream.The need for a con-
tingency plan designed to study all subpopulations of moose
during a severe winter,was rei terated.
x
Potential impact mechanisms were listed along with particular
associated affects.General mechanisms considered were the fol-
lowing:1)altered seasonal river flow patterns and loss of
annual variation in river flow,2)altered water temperature,3)
al teration of habitat,4)increased access,5)human encroach-
ment,6)increased railway and vehicular traffic,7)loss of
habitat at impoundment,8)salt water encroachment at Cook Inlet,
9)altered turbidi ty and 10)altered ecosystem.
Recommendations for future research included:1)continuation of
present monitoring of radio-collared moose,2)radio-collar addi-
tional individuals,particularly males,north of Talkeetna,3)
radio-collar additional males south of Talkeetna,4)continue
floodplain censuses during the winter of 1983-84,5)capture and
radio-collar moose in disturbance subclimax vegetative sites
studied in previous years and 6)design and be prepared to imple-
ment a severe winter contingency study plan.
xi
-
-
ACKNOWLEDGEMENTS
The following persons deserve special thanks for various phases
of this study:
K.Schneider,Alaska Dept.Fish and Game,for providing numerous
helpful suggestions and comments on all aspects of the research
and for his willingness to ease the burden of administrative
tasks and meetings which occa:;>ionally occurred at inopportune
times.
D.C.McAllister,Alaska Dept.Fish and Game,for willing and
able assistance and suggestions and comments in all aspects of
this study.
V.Loftstedt,Kenai Air Alaska,Inc.,and J.Swiss,John Swiss
and Family,big game guiding,outfitting and air charter service,
for piloting the helicopter and fixed-wing aircraft,respectively
during the live capture and radio-collaring of moose.
Dr.C.C.Schwartz,T.H.Spraker,M.A.Chihuly,all Alaska
Dept.of Fi sh and Game employees,for their assi stance in the
capture and radio-collaring of moose.
C.Allen,Charlie Allen Flight Service,and M.Houte and
C.Loftstedt,Kenai Air Alaska,Inc.,for piloting aircraft on
the many long and tedious radio-relocating surveys.They deserve
special recognition for abi Ii ty,desire and safety.
xii
N.Tankersley,Alaska Dept.Fi sh and Game,for frequent assi s-
tance on radio-relocating surveys.
J.Swiss,John Swiss and Family,big game guiding,outfitting and
air charter service,for his ability and safety in piloting and
navigating aircraft on patterned aerial censuses for moose and
for his enthusiasm in helping to spot moose during those
censuses.
D.Anctil,T.Otto and S.Miller,all Alaska Dept.Fish and Game
employees,for assi stance in management and analysi s of data.
C.Reidner,Alaska Dept.Fish and Game,for drafting the figures.
H.Griese,B.Taylor and M.Chihuly,all Alaska Dept.Fish and
Game employees,for occasional assistance on radio-relocation
surveys.
E.Goodwin,Alaska Dept.Fish and Game,for processing samples of
blood from moose.
P.Miles and S.Lawler,Alaska Dept.Fish and Game employees,for
tolerating the many corrections,changes and redrafts of redrafts
and lengthy tables which occurred in the typing of this report.
xiii
~.
-
If1ii(IIBJ
-
TABLE OF CONTENTS
Page No.
SDrIIMARY
ACKNOv-1LEDGEMENT S
LIST OF TABLES
LIST OF FIGURES
INTRODUCTION
STUDY AREA
IvIETHODS
FINDINGS AND DISCUSSION
WINTER FLOODPLAIN CENSUSES
. ..
iii
xii
.xvi
.xx
1
7
.10
.18
.18
AFFINITIES FOR RIPARIAN HABITATS . . . . . . . . . .35
.~
-
-
MOVEMENTS OF RADIO-COLLARED MOOSE .
PRODUCTIVITY AND SURVIVAL OF YOUNG
PUBLIC USE OF MOOSE RESOURCE
MORTALITY ..
Capture Related
Non-Hunting Mortality
Hunting Mortality
Quantified By Sex,Subunit And
StUdy Area
POPULATION PHENOMENA
HABITAT REHABILITATION
LIMITATION OF SAMPLES AND SAMPLING EFFORT
POTENTIAL MAJOR IMPACT MECHANISMS .
RECOMMENDATIONS FOR FUTURE RESEARCH
REFERENCES . . . . .
xiv
.42
.65
.70
.80
.80
.81
.85
.87
.92
.97
101
105
107
110
APPENDIX A.
APPENDIX B.
TABLE OF CONTENTS (cont'd)
Individual visual collar number,
radio transmitter and ear tag
numbers,date of capture,sex
and maternal status for moose
radio-collared in February and
March on the Susitna River
between the Delta Islands and
Cook Inlet,Alaska,1982 .
History of maternal status
indicated by the presence of
calves for individualfemale
moose radio-collared along the
Susitna River from Cook Inlet
to Devil Canyon,Alaska and
subsequently radio-relocated,
1980-82.
xv
Page No.
.113
.114
-
-
-
-
-
Table 1.
Table 2.
Table 3.
Table 4.
Table 5.
Table 6.
Table 7.
Table 8.
LIST OF TABLES
Inclusive calendar dates of theoreti-
cal ranges based on life history
phenomena for populations of moose
along the Susitna River from Devil
Canyon to Cook Inlet,Alaska.
Sex,age composition and zone of
location for moose observed on the
1 and 2 March aerial census of the
Susitna River from Devil Canyon to
Cook Inlet,Alaska,1982
Sex,age composition and zone of
location for moose observed on the
23 and 24 March aerial census of the
Susitna River from Devil Canyon to
Cook Inlet,Alaska,1982
Sex,age composition and zone of
location for moose observed on the
12 April aerial census of the
Susitna River from Devil Canyon to
Cook Inlet,Alaska,1982
Sex,age composition and zone of
location for moose observed on the
29 October and 6 November aerial
census of the Susitna River from
Devil Canyon to Cook Inlet,Alaska,
1982
Sex,age composition and zone of
location for moose observed on the
10 and 18 November aerial census of
the Susitna River from Devil Canyon
to Cook Inlet,Alaska,1982
Sex,age composition and zone of
location for moose observed on the
1,2 and 6 December aerial census of
the Susitna River from Devil Canyon to
Cook Inlet,Alaska,1982
Sex,age composition and zone of
location for moose observed on the
20,21 and 22 December aerial census
of the Susitna River from Devil Canyon
to Cook Inlet,Alaska,1982
xvi
-.
Page No.
.13
.20
.21
.22
.23
.24
.25
.26
LIST OF TABLES (cont'd)
Table 9.Sex,age composition and zone of
location for moose observed on the
5 and 6 January aerial census of the
Susitna River from Devil Canyon to
Cook Inlet,Alaska,1983
Table 10.Sex,age composition and zone of
location for moose observed on the
20 and 24 January aerial census of
the Susitna River from Devil Canyon
to Cook Inlet,Alaska,5 and 6 Jan-
uary,1983
Table 11.Sex,age composition and zone of
location for moose observed on the
7 and 9 February aerial census of the
Susitna River from Devil Canyon to
Cook Inlet,Alaska,1983
Table 12.Percent of calves observed on each
of 13 censuses for moose in flood-
plain habitat along 4 zones of the
Susitna River between Devil Canyon
and Cook Inlet,Alaska,1981-83
Table 13.Surface area (km 2 )of floodplain
habitat types in four geographic'al
zones of the Susitna River between
Devil Canyon and Cook Inlet,Alaska
Table 14.Timing and frequency of use of
Susitna River riparian habitats
by individual radio-collared female
moose,between Talkeetna and Devil
Canyon,Alaska,1981-82 .
Table 15.Dates indicating chronology of
departure from Susitna River
riparian habitat for female and
male moose radio-collared in
habitats downstream from
Talkeetna~1980-82
Table 16.Variation in and general
affinities for floodplain
habitats of the Susitna
River exhibited by moose
radio-collared and relocated
periodically during complete
yearly periods
xvii
Page No.
.27
.28
.29
.32
.34
.36
.38
.40
-
~,
-
-
-
-
LIST OF-TABLES (cont'd)
Page No.
-
Table 17.Array of maximum distances between
the capture site and a relocation
site,for individual,female and
male moose,radio-collared in dif-
ferent areas along the Susitna River,
Alaska and monitored between 0 and 3
annual cycles,1980-82
Table 18.Variation in calculated range size
within and between individual,female
and male moose radio-collared in two
areas along the Susitna River,Alaska
and monitored different periods of
time,1980-82 .
Table 19.Monthly summaries of female radio-
collared moose and associated calves
observed along the Susitna River
during radio-tracking flights,
1980-82 .
Table 20.Transportation type,effort,number
of moose killed,number of hunters
and their residence for participants
in the 1979-80,1980-81 and 1981-82
open hunting seasons in Game Management
Unit 14B,Alaska
Table 21.Sex and number of moose killed and
number of applicants for limited
entry,lottery type hunts in Game
Management Unit 14B for the 1979-80,
1980-81 and 1981-82 hunting seasons
Table 22.Transportation type,effort,number
of moose killed,number of hunters
and their residence for participants
in the 1979-80,1980-81 and 1981-82
open hunting seasons in Game Management
Unit 16A~Alaska
.56
.58
.66
.71
.72
.73
Table 23.Number of moose killed and applicants
for limited ~ntry lottery type cow
permit hunts in Game Management Unit
16A for the 1979-80,1980-81 and 1981-82
hunting seasons..74
xviii
LIST OF TABLES (cont/d)
Table 24.Transportation type,effort,number
of moose killed,number of hunters
and their residence for participants
in the 1979-80,1980-81 and 1981-82
open hunting seasons in Game Management
Unit 13E,Alaska
;
Table 25.Hunting and non-hunting mortality
for individual,male and female
moose captured and radio-collared
along the Susitna River between
Devil Canyon and Cook Inlet and
resident in Alaska Game Management
Subunits 13E,16B,16A,14A and 14B
while monitored 1980-82
Table 26.Numbers,sex and age of moose observed
in areas adjacent to the Susitna River
floodplain where vegetation and plant
succession have been altered by activities
of man,Alaska 1981-83
xix
Page No.
.75
.88
.99
-
-
-
-
Fig.1.
Fig.2.
Fig.3.
Fig.4.
Fig.5.
Fig.6.
Fig.7.
Fig.8.
LIST OF FIGURES
Map showing location of the study area
in Alaska with names listed for rivers,
lakes and other prominent landscape
features.
Map of study area showing locations of
Game Management Subunits,State and
National Parks and areas where vege-
tation and/or plant succession has been
disturbed by activities of man.
Locations of capture for 13 moose radio-
collared 24 February,2 moose radio-
collared 26 February,and 3 moose radio-
collared 10 Ma~ch on the Susitna River
between the Delta Islands and Cook Inlet,
Alaska,1982.
Polygon encompassing 2178 relocation points
for 10 moose radio-collared 17 April 1980,
29 moose radio-collared 10-12 March 1981
and 17 moose radio-collared 26 February -
10 March 1982 along the Susitna River
between Devil Canyon and Cook Inlet,Alaska
and monitored through 20 October,1982.
Radio-relocations for 40 female moose
captured and radio-collared along the
Susitna River between Devil Canyon and
Cook Inlet,Alaska,1980-82
Radio-relocations for 15 male moose
captured and radio-collared along the
Susitna River between Devil Canyon and
Cook Inlet,Alaska,1980-82 .,
Locations where 40 female moose captured
and radio-collared along the Susitna River
between Devil Canyon and Cook Inlet,Alaska
were radio-relocated during the calving I
period,1980-82
Locations where 12 male and 39 female
moose captured and radio-collared along
the Susitna River between Devil Canyon and
Cook Inlet,Alaska were radio-relocated
during the summer period,1980-82 .
xx
Page No.
. 8
. 9
.11
.43
.45
.46
.48
.49
",
Fig.9.
Fig.10.
Fig.11.
Fig.12.
Fig.13.
Fig.14.
Fig.15.
!
I"
LIST OF FIGURES (cont'd)
Locations where 11 male and 38
female moose captured and radio-
collared along the Susitna River
between Devil Canyon and Cook Inlet,
Alaska were radio-relocated during
the month of September,1980-82
Locations where 38 female moose
captured and radio-collared along
the Susitna River and Devil Canyon
and Cook Inlet,Alaska,were radio-
relocated during the rut period,
1980-82
Locations where 11 male moose captured
and radio-collared along the Susitna
River between Devil Canyon and Cook
Inlet,Alaska,were radio-relocated
during the rut period,1980-82.
Locations where 7 male and 40 female
moose captured and radio-collared
along the Susitna River between
Devil Canyon and Cook Inlet,Alaska,
were radio-relocated during the
winter period,1980-82.
Variation in size and shape of ranges
determined for 4 female moose captured
and radio-collared along the Susitna
River downstream from Devil Canyon
and mo~itored from March 1981 through
September 1982.
Variation in size and shape of ranges
determined for 4 moose captured and
radio-collared along the Susitna
River downstream from Devil Canyon
and monitored from April 1980 through
September 1982.
Shape and spatial ralatio~ips for
ranges of 8 male moose captured and
radio-collared along the Susitna
River between Devil Canyon and Cook
Inlet,Alaska and monitored during
1980-82 .
xxi
Page No.
.50
.52
.53
.54
.59
.60
.61
-
-
-
-
-.
·1,,
Fig.16.
Fig.17.
.Fig.18.
LIST OF FIGURES (cont'd)
Shape and spatial relationships
for ranges of 10 female moose
captured and radio-collared along
the Sutitna River between Devil
Canyon and Cook Inlet,Alaska and
monitored during 1980-82.
Shape and spatial relationships for
ranges of 12 female and 1 male moose
captured and radio-collared along the
Susitna River between Devil Canyon and
Cook Inlet,Alaska and monitored
during 1980-82.
Spatial relationships for hypothetical
subpopulations of moose in the Susitna
River watershed between Devil Canyon and
Cook Inlet,Alaska.
xxii
Page No.
.62
.63
.93
INTRODUCTION
More than 30 years ago,the search for an economical source of
power to serve Alaska 's railbel t region stimulated interest in
construction of a hydroelectric faci Ii ty on the upper Susi tna
River.Feasibility assessments then,by the u.s.Bureau of
Reclamation and subsequently by the U.S.Army Corps of Engineers
indicated that the proposed project was economically feasible and
that environmental impacts would not be of .sufficient magnitude
to affect its authorization.
More recently,in response to an anticipated demand for a non-
fossil fuel source of energy,previous ideas and plans were
rejuvenated in 1976 as attention was again focused on a Susitna
River hydroelectric project.At that time,the Alaska State
Legislature created the Alaska Power Authority to administer
detailed studies to re-evaluate the feasibility of developing the
hydroelectric potential of the upper Susitna River,since tech-
nical field research studies designed to assess environmental
impacts of such a project were never adequately addressed in the
past and in recent times,regulations and public sentiment for
environmental conservation have become increasingly more conser-
vative.
Environmental impacts of the proposed hydroelectric project can
be divided into 2 general hydrological categories:those up-
stream (pre-impoundment)and those downstream (post-impoundment)
1
-.
-
-
-
from the impoundments.Initial environmental impact assessments
emphasized concern in the pre-impoundment area;environmental
assessments in the post-impoundment area were "token ll in nature.
1-Perhaps,conceptually,acute effects involving loss of habitats
through inundation were considered to be more significant than
habitats downstream as a result of altered characteristics of the
stream section of river;indirect effects will also be realized
assessment of the types and magnitude of influence of the Susitna
For migratory species of
environmental impacts resulting from altered
occur immediately along the river.
Susi tna River,
the river is as important to determine as those impacts that
wildlife,ultimate effects of proximate impacts may be geograph-
in a corridor of terrestrial habitats adjacent to the river.An
ically distant and not obvious,but should not be overlooked nor
River hydraulics on environments at perpendicular distance~from
water and hydrologic flow regimes."
indirect,long-term chronic type effects that would occur in
Though impoundments will be located in the upper reaches of the
hydrologic flow regimes will occur throughout the 215 km down-
1
.1
""""
regarded lightly.
The Susitna River flows about 215 km downstream from Devil Canyon
before entering Cook Inlet.In a narrow sense,the surrounding
Susitna River Valley watershed encompasses approximately 800,000
km 2 of extremely productive habi tat for many species of wildlife.
2
Perhaps,its innate value as wintering habitat for moose (Alces -
alees gigas Miller)is unsurpassed elsewhere in the State.
Prior to statehood,the Susi tna Valley was ranked as the most
".i
1
productive moose habitat in the territory (Chatelain 1951).
During this same time period,some wintering areas were said to -
sustain moose at concentrations greater than 22/km 2 (Spencer and
Chatelain 1953).More recent evidence indicates that concentra-
1959).Such dense aggregations are the probable result of moose
when deep snows in surrounding areas and at higher elevations
as remote as 30-40 kmsome
persist into late winter and obscure browse species (Rausch
from numerous subpopulations,
tions and densities of moose in the Susi tna Valley are greatest
(LeResche 1974)to more than 110 km away (Van Ballenberghe 1977),
gathering to seek refuge and forage in lowland habitats.It
appears that many moose,from an extensive area and numerous sub-
populations,utilize winter range in the Susi tna River Valley.
The desirability of this area for moose in the early 1950's was
greatly enhanced by early successional stages of vegetation
resulting from wildfires,mild winters,and abandonment of land
cleared for homesteads,highway and rai lroad construction and
rights of way.
By the 1970's,browse on previously cleared land had been lost
through succession,strict fire suppression efforts had essen-
-
3
,
" I
j
j
r""\
tially eliminated fire subclimax vegetation,and moose popula-
tions began to decline in response to the loss of important
winter range browse species.In subsequent years,several severe
winters compounded the population decrease.A low proportion of
~
i i. I
I
males in the breeding population may also have been another con-
tributory factor (Bishop and Rausch 1974).Presently,many habi-
tats in the Susitna River Valley have reverted to the pre-1930
pristine state and populations of moose have responded accord-
.,
!
ingly.This does not mean that the area is any less important to
moose than in the early 1950 1 s,but that fewer moose may be using
it.
,f
j In the past,wildfire and extensive land clearing were the most
mena,as beaver activity,periodic flooding,ice scouring,ripar-
dominant disruptive factors involved in creation and maintenance
ian erosion,and aluvial or loess translocation of soil,which
Other pheno-of young second-growth browse species for moose.
acted on a smaller and less dramatic scale,were primarily res-
tricted to riparian habitats along the Susitna River,and were
j
,~considered to be relatively insignificant.
However,recent policies and efficiency in suppress~on of wild-,
fire and disposal of only small parcels of land for private
"homesites ll instead of larger parcels for IIhomesteads"have,for
all practical purposes eliminated the influence of fire and land
clearing on habitat alteration.For these same reasons,disrup-
ti ve factors once viewed as of li ttle significance have become
paramount in the creation and maintenance of habitats and browse
species for moose wintering in the"Susi tna River Valley.
4
In the near future,habitats in the Susitna River Basin may again
experience a broad ecological perturbation if the hydrologic
regime and other characteristics of the Susitna River are altered
to accommodate hydroelectric development.Though alterations in
the flow regime and other characteristics of the Susitna River
(temperature,turbidity,ice formation and scouring,substrate
erosion and deposition,ice fog,icing of vegetation,and etc.)
could impact moose in a number of ways;one of the most profound
would be through changes in vegetative communi ties which occur
along the river course to the extent that critical habitats or
winter browse species were no longer available to various subpop-
ulations of moose.
The present research study was designed to assess the potential
impacts of the proposed Susitna River hydroelectric project on
subpopulations of moose which are ecologically affiliated with
that portion of the Susi tna River between the proposed Devil
Canyon impoundment and Cook Inlet and to suggest possible
actions for mi tigating those impacts.
Primary objectives of this study are the following:1)to ident-
ify subpopulations of moose that are ecologically affiliated with
the Susitna River downstream from Devil Canyon;2)to determine
seasonal distribution and movement patterns for each identified
subpopulation;3)to determine timing,location and relative
magni tude of moose use of various riparian habitats along the
5
-
-
-.
J
lower Susitna River;4)to identify specific mechanisms through
which impacts will be transferred to subpopulations of moose;
5)to determine the probable nature and approximate magnitude of
identified impacts on those particular subpopulations of moose;
6)to delineate a zone in which impacts of the proposed hydro-
electric proj ect may affect subpopulations of moose i and 7)to
determine and suggest potential options for mitigating actions.
The following report is an interim update to the Phase I Final
Report (Modafferi 1982)and largely addresses studies continuing
between 15 October 1981 and 20 October 1982.
Though this report is based primarily on information obtained·
since completion of .the Phase I report,where appropriate,both
data sets are integrated to provide a more complete and meaning-
ful assessment of particular findings.
More detailed overall accounts of the Introduction,Study Area·
and Methods pertinent to this study are available in the Phase I
Final Report (Modafferi 1982)and will not be t'reated again here.
6
STUDY AREA
_.
The Susitna River flows about 215 km downstream from the proposed
Devil Canyon dam site before emptying.into Cook Inlet.In its -
course to the sea,it descends about 300 m in elevation,it
accepts glacial and non-glacial contributions from numerous trib-
utary streams,its character changes greatly and it is a dominant
force influencing characteri stic s of adj acent terrestrial habi-
tats along the way (Fig.1).The map in Fig.I,excluding labels
for features,is used as a geographical base for many other
figures in this report.A more detailed description of the
general ecological features in the Susitna River Valley are
available in Modafferi (1982).
Boundaries delineating the research study area will be determined
by the extent of actual movements documented for moose which were
known to utilize habitats along the Susitna River.Until further
research proves otherwise,it will be assumed that moose which
use Susitna River floodplain habitat in any manner,in any sea-
sonal period for any length of time may be impacted by hydro-
electric development.Ultimately,the spatial area o~zone where
impacts may be realized by subpopulations of moose will encompass
all movements of all moose which were at one time known to use.
Susi tna River floodplain habi tats.
Boundaries for geographical areas in which human use of the moose
resource is administratively regulated and locations of other
areas where.plant succession has been altered and which provide
attractive winter range for moose are noted in Fig.2.
7
......
-
"""'.
_.
;CHEEK
WILLOW
A Big'leland
B Bell leland
C .Mount Sueltna
D Little Mount Sueltna
E Lower Beluga Lake
F Beluga Mountain
G Venia Hille
H Amber Lake
I Trapper Lake
"Delta'lelande
K Redehlrt Lake
L Dey'"Can,on
Dam'Siteo11::'=i°_-=~IfI_=20:ilk,"
NO'""
.."..-"-
1
Figure 1.Map showing location of the study area In Alaska with name.·
nated for rIver ••lakes and othe,prominent landscape feature ••
8
i
j
j
1
j
1
l
1
J.~
·'i
1~r
.j
-i-~
.-~
··1
]
'\
".:~
1
1
j
1
j
1
i
"I
.;,
..i
\
o
(:;
,/A Talk ••tna W ••t
B Montana W.st
C Montana Nortn
D Montana Mlddl.e Montana South
F Ka.nwltna Lak.Nortn
-
-
-
Flgur.2.Map of study are.showing locations of Gam.Management
Subunits (13E.14A.14B.16A and 16B).State and National Parka and
areaa whera vegetation and/or plant auccession has been disturbed by
activIties of man (A -F)..
9
of"'"
In order to provide individually identifiable animals that could
be located regularly,samples of moose were captured and tagged
with visual and radio transmitting collars.Each collar featured
a discrete number and radio frequency.
For tagging,moose were captured during the winter wi thin the
banks of the ice and snow covered Susi tna River between Sheep
Creek and Sherman in 1980,between the Delta Islands and Portage
Creek in 1981 (Modafferi 1982)and between the Delta Islands and
mg/cc,respectively)administered intramuscularly with Palmer
Cap-Chur equipment by personnel aboard a hovering Bell 206B heli-
Typically moose were immobilized with an etorphine (M-99):rom-
Immobilized moose were revived with an intraveneous
pum (xylazine hydrochloride)mixture (10-12:Icc @ 9 mg and 100
captured up to 400 m-on either side of the river proper.
unavailability of moose north of Talkeetna,some individuals were
copter.
Cook Inlet in 1982 (Fig.3 and Appendix A).Due to the relative
injection of diprenorphine (MSO-SO,10-12cc @ 2 mg/cc).
y.lhile immobilized moose were collared,measured,palpated for
feti,tagged with monel metal ear tags,a sample of whole blood
was taken,an incisor tooth was extracted,physical conformation
was assessed and for females,association with calves was noted.
Moose immobilized in 1982 were not palpated.
10
-
-
-
r..~rIN
iF=...,.....,l=="r"""-~I
10 0 20 Icmo
NORTH
Figure 3.Locations of capture for 13 moose radio-collared 24 .february (#40.41.75._
76.78~87,94. 95.96.97.98.99,100),2 moose radio-collared 26 February (#39.44)
and 3 moose radio-collared 10 March (#58,71,93)on the Susltna River between the
Delta Islands and Cook Inlet.Alaska.1982.(circled numbers =males)
,,
General health of captured moose-~was assessed by assigning each
individual a rating of condition based on physical conformation
(fatness,robustness,or lack of).Condi tion was rated on a
1
l
"'}
.i""""
I"'"
I
scale from 1 to 10i a rating of 7 indicated that the animal was
in average to better than average health.
Relocation flights with Cessna 172,180 or 185 aircraft equipped
with a yagi antenna on each wing were conducted at intervals of
about two-three weeks in 1980 and about every 10-14 days in 1981
and 1982._Inclement weather occasionally altered this schedule.
To relate and illustrate the relative use and timing of use of
Susi tna River floodplain habitats by moose a descriptive tech-
nique based on life history phenomena and their inclusive calen-
dar dates,was employed.A description of the life history base
and inclusive calendar dates for those periods are presented in
Table 1.
Calendar dates for the ranges did not encompass the entire year.
Between dates for ranges,intervals were delineated to accommo-
date movement or transition from one range or period to another.
To prevent transitory movements from affecting cal?ulation of
location,a very narrow spread of inclusive dates was -selected to
describe locations for respective life history activity periods.
Perhaps determination of extent of these ranges suffered at the
expense of their location,but the latter data and their spatial
relationship to the Susitna River were considered to be of
greater importance and relevance in thi s study.
12
Table 1.Inclusive calendar dates of theoretical ranges based on life history phenomena for
populations of moose along the Susitna River from Devil Canyon to Cook Inlet,Alaska.
/
Range or transitory interval
Winter range
Spring transitory interval
Calving range
Summer transitory interval
Summer range
Autumn transitory interval
Breeding range
Post breeding transitory interval
Relevance to life history
Males recondition from breeding.
Pregnant females nurture fetus and
prepare for parturition.
First winter for calves.
Females bear young.
Growth of new born young.Females
recondition from parturition and
lactation.Males begin antler
growth.
Males establish breeding units.
Sexes breed.
Location of breeding perhaps
critical for denoting subpop-
ulation units.
13
Calendar dates
1 January
thru
28 February
10 May
thru
17 June
1 July
thru
31 August
14 September
thru
31 October
.-
-
-
-
-
-
-
.~
To indicate spatial distribution for potential consumptive use of
moose which use Susi tna River riparian habitats,locations of
radio-collared moose during the the usual open hunting season are
presented.
data management,see Miller and Anctil (1981).Three subsamples
scale USGS topographic maps and later transferred to mylar over-
Locations (audio-visual or audio)of moose were noted on 1:63,360
For more complete details oflaysforcomputerdigitization~
1
of moose provided information on movements,population identity,
habitat·use,physical condition and productivity;a subsample of
10 moose captured between Sheep Creek and Sherman on 17 April
1980,a subsample of 29 moose captured between the Delta Islands
and Portage Creek on 10-12 March 1981 and a sUbsample of 18 moose
captured between the Delta Islands and Cook Inlet on 24 February,
3 and 10 March 1982.This report contains data on radio-collared
moose monitored through 20 October 1982,at which time up to 78,
57 and 19 relocations were available for some individuals cap-
tured in the 1980,1981 and 1982 samples,respectively.
Moose use the Susitna River year round;however,circumstantial
evidence indicated that the magnitude (time and numbers)of use
is significantly greater during the winter and particularly so
during winters characterized by deep snows which persist late
into early spring (Rausch 1958).In order to determine the mag-
nitude of use,to delineate the timing of use and to determine
the location and spatial distribution of use,a series of peri-.
odic censuses were conducted within the floodplain of the Susitna
River from Cook Inlet to Devil Canyon.
14
By the time I became familiar with this project in early 1981,
radio collared moose had already begun to leave the Susitna River
floodplain and censuses then would have been futile.No periodic
river census were conducted in the winter of 1980-81.
In the winter of 1981-82 censuses were conducted on 9 and 10
December,28 December and 4 January,2 and 6 February,1 and 2
March,23 and 24 March and 12 April.During the winter of 1982-
83 censuses were conducted on 29 October and 6 November,10 and
18 November;I,2,and 6 December;20,21 and 22 December;5 and
6 January,20 and 24 January;and 7 and 9 February.Though the
timing of these censuses extended beyond the October cut-off date
for radio-~elocation data included in this report,salient
aspects of those censuses are presented and analyzed here due to
their relative importance in this study.
Aerial river censuses were conducted with a FA-18 aircraft flown
at low elevation in a parallel transect pattern from floodplain
bank to opposite floodplain bank,up the Susitna River from Cook
Inlet to Devil Canyon.Weather and numbers of moose counted
affected duration of individual censuses.Though limitations of
aerial surveys of moose were known (LeResche and Rg.usch 1974),
the object of aerial river censuses was to count all moose within
the banks of the Susitna River floodplain and any of its inter-
connecting sloughs.During aerial river censuses the following
-
-
--
-
-
categories of moose were distinguished:
15
large antlered males,
I
,~
1
small antlered males,lone non-antlered animals,females with one
calf,females wi th two calves,and lone calves.
Location of each moose observed was recorded on USGS 1:63 ,360
scale topographic maps.Additional aerial river censuses will be
conducted between mid-February and mid-April,through the winter
of 1982-83.
River censuses were conducted over a time period to encompass the
build up,peak and decline in moose use of winter range in
Susi tna River floodplain habitats.Censuses were conducted at
frequent intervals to assess population dynamics in moose use of
these floodplain habitats and to correlate those data with
factors which may be-responsible for observed dynamics.
To calculate densities of moose which were observed wintering in
habitats within each of the four riparian zones on each census of
Susitna River floodplain habitats,surface area surveyed was
determined by making visual estimates of those land areas as they
appeared on 1:63,360 scale USGS topographic'maps.These visual
estimates revealed that riparian zones I,I I,I I I and IV each
contained 28 and 31,23 and 21,65 and 104 and 65 and 29 km 2 of
1
aguatic and terrestrial habi tats ,respectively.
Attempts will be made to determine why some habitats or areas are
more attractive to moose (food,cover,geographic location,and
etc.)than,others,if aerial river censuses reveal non-random
distribution of moose along the river course.
16
"\
I Information on consumptive use of the moose resource in areas
adjacent to the Susitna River was provided by hunter kill records
obtained from Alaska Department of Fish and Game harvest ticket
master file.
Information on producti vi ty of moose that are affi liated wi th
habitats along the Susitna River was gathered from 2 sources:1)
observation of radio-collared female moose during routine aerial
relocation flights and 2)aerial river censuses .
•
17
~)I;
-
-
-.
-
,~
FUIDINGS AND DISCUSSION
WINTER FLOODPLAIN CENSUSES
Interaction between hydraulics of the Susitna River and adjacent
terrestrial ecosystems have,over time,resulted in a hetero-
geneous assemblage of early successional plant communities which
along with local climatic conditions appear to provide attractive
winter range for moose (Collins 1983).
Greatest use of Susitna River riparian habitats·by moose gener-
ally occurs between November and April when moose are attracted
to floodplain areas because of more shallow snow conditions
and/or greater availability of winter forage (Rausch 1958).
Periodic censuses of floodplain habitats wi thin a given winter
and over several winters provide information on:1)when moose
seek these habitats;2)which habitats or areas are most attrac-
tive to moose;3)numbers of moose which utilize floodplain habi-
tats in a particular winter;4)numbers of moose which floodplain
habitats may potentially support;5)sex and age-class specific
use of riparian habitats,and 6)when moose depart from these
habi tats.Surveys conducted prior to an influx or a~fter depar-
ture of wintering subpopulations may additionally provide indi-
rect information on numbers of moose which are resident to flood-
plain habitats throughout the year.
18
Information obtained from thirteen censuses for moose in flood-
plain habitats along the Susi tna River downstream from Devil
Canyon to Cook Inlet (Modafferi 1982 and Tables 2-11)substan-
tiate beliefs of Rausch (1958)and others (Chatelain 1951 and
LeResche 1974)about behavior of the "railbelt populations"of
moose and their use of winter range along the Susitna River.Six
of the censuses were conducted from 9 December through 12 April
during the relatively mild winter of 1981-82 and seven censuses
have been conducted from 29 October through 9 February during the
winter of 1982-83.The latter winter was characterized by record
snowfalls in October and November but climatic conditions from
December through mid-February were mild and generally similar to
those of the previous winter.
•
During the winter of 1981-82 the greatest number of moose (369)
were observed on the 1 and 2 March 1982 census,in spite of rela-
tively poor counting conditions in river zone IV.Though census
4 yielded the greatest total number of moose,more moose were
observed in zones I,II and IV on censuses 3,5 and 1,respec-
tively.Consid~ring these findings,the maximum number of moose
observed in zones I-IV were 36,25,238 and 123,respectivelYi an
aggregate total of 422 different moose.For these calculations,
it is assumed that no movement of moose occurred betWEen differ-
ent zones over the time period between censuses.Data from
radio-collared moose lead me to believe this assumption is not
greatly violated.If movements did occur up or down the river,
there is little reason to believe that they would not be coun-
tered by similar movements in the opposite direction.
19
-
-
~\
-
-
Table 2.Sex,age composition and zone of location for moose observed on the 1 and 2 March
aerial census of the Susitna River from Devil Canyon to Cook Inlet,Alaska,1982.
Total
Snow cover incomplete in this zone;conditions for observing moose less than ideal.
1m =small antlered males,mostly yearlings~probably some two-year old males;
Ad =males with large antlers.
Total
Calves Moose
0 7
4 17
37 238
21 107
62 369
=Montana
Census #4
Males 2 Females 3 Lone
Ad fm w/o w/l W12 calves Ads .
0 0 7 0 0 0 7
0 0 10 2 1 0 13
0 0 165 35 1 0 201
0 0 68 15 3 0 86
0 0 250 52 5 0 307
I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III
Creek to Yentna River and IV =Yentna River to Cook Inlet.
W/O =females without young,Wil females with one young;W/2 females with 2
young.The WIO category also includes males,most.of which have shed their
antlers by mid-December.
2
4
1
3
I.~
20
Table 3.Sex,age composition and zone of location for moose observed on the 23 and 24 March
aerial census of the Susitria River from Devil Canyon to Cook Inlet,Alaska,
1982.
Census #5
21
-
-
-
-
-
Table 4.Sex,age composition and zone of location for moose observed on the 12 April
aerial census of the Susitna River from Devil Canyon to Cook Inlet,Alaska,
1982.
22
Table 5.Sex,age composition and zone of location for moose observed on the 29 October and
6 November aerial census of the Susitna River from Devil Canyon to Cook Inlet,
Alaska,1982.
Census #7
-
-
River Males 2 Females 3 Lone Total
1 Ad 1m WID w/l w/2 calves Ads Calves Moose ,Ml.W..
zone
I 2 1 7 4 0 0 14 4 18
II 0 0 2 1 0 0 3 1 4
III 2 5 18 13 3 0 41 19 60
IV 4 9 7 25 20 2 2 63 26 89
Total 13 13 52 38 5 2 121 SO 171
1 I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III =Montana Creek
to Yentna River and IV =Yentna River to Cook Inlet.Zones I,II and III-IV were
censused on 6 November and 29 October,respectively."""!\
2 1m =small antlered males,mostly yearlings,probably some two-year old males;
Ad =males with large antlers.
3 W!O =females without young,W!l females with one young;W!2 females with 2 young...~
4 Snow conditions in this zone excellent for observing moose.
~.
23 -
Table 6.Sex,age composition and zone of location for moose observed on the 10 and
18 November aerial census of the Susitna River from Devil Canyon to Cook
Inlet,Alaska,1982.
Census #8
River
Total
1zone-
Males 2 Females 3 Lone Total
Ad 1m WID WIl W/2 calves Ads Calves Moose
10 4 23 10 0 0 47 10 57
0 0 8 10 0 0 18 10 28
20 17 87 46 5 1 175 57 232
17 10 53 36 2 1 118 41 159
47 31 171 102 7 2 358 118 476
1m =small antlered males,mostly yearlings,probably some two-year old males;
Ad =males with large antlers.
WIO =females without young,Wil females with one young;W/2 females with 2 young.
The wlO category-includes males which have shed their antlers;this becomes
prevalent by mid-December.
Snow cover in this zone excellent for observing moose.
I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III =Montana Creek
to Yentna River and IV =Yentna River to Cook Inlet.
4
2
III
IV 4
II
I
3
1
j
24
Table 7.Sex,age composition and zone of location for moose observed on the 1,2 and 6
December aerial census of the Susitna River from Devil Canyon to Cook Inlet,
Alaska,1982.
Census #9
River Males 2 Females 3 Lone Total
zone 1
Ad 1m 1'1/0 W!l w12 calves Ads Calves Moose
I 4 5 42 11 1 0 63 13 76
II 1 9 16 9 0 2 35 11 46
III 4 12 10 101 67 11 2 201 91 292
IV 5 31 21 220 61 6 0 339 73 412
Total 48 45 379 148 18 4 638 188 826
-
~!
1
2
3
4
5
I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III =Montana Creek
to Yentna River and IV =Yentna River to Cook.Inlet.
1m =small antlered males,mostly yearlings,probably some two-year old males;
Ad =males with large antlers.
1'1/0 =females without young,1'1/1 females with one young;1'1/2 females with 2 young.
The 1'1/0 category includes males which have shed their antlers;this becomes
prevalent by mid-December.
Frost and snow on vegetation during survey of Zone III made observing moose difficult;
counts may be relatively lower than in other zones.
Snow conditions in this zone excellent for observing moose.
25
-
-
Table 8.Sex,age composition and zone of location for moose observed on the 2D,21 and 22 December census 0
the Susitna River from Devil Canyon to.Cook Inlet,Alaska,1982.
Census :It 10
River Males 2 Females3 Lone Total
1 Ad 1m WID W/l W/2 calves Ads Calves Moose
zone
I 4 8 3 36 13 1 0 61 15 76
II 1 4 28 20 4 1 57 29 86
III 2 13 204 104 ID 3 333 127 460
IV 5 9 11 163 62 1 2 246 66 312
Total 2D 31 431 199 16 6 697 237 934
1m =small antlered males,mostly yearlings,probably some two-year old males;
Ad =males with large antlers.
WID =females without young,Wil females with one young;W/2 females with 2 young.The
WID category includes males which have shed their antlers;this was prevalent by
mid-December.
Snow conditions in zones I-III good to excellent for counting moose.
Snow conditions fair (patchy,dusty,and melted out)and flying conditions fair
(windy)during census of this zone;overall conditions fair for observing moose.
Montana Creek toI =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III
Yentna River and IV =Yentna River to Cook Inlet.
4
2
5
3
1
26
Table 9.Sex,age composition and zone o~location for moose observed on the 5 and 6 January
aerial census of the Susitna River from Devil Canyon to Cook Inlet,Alaska,5 and 6
January 1983.
Census #:11
River Males 2 Females3 Lone Total
1 Ad 1m W/O W/l W/2 calves Ads Calves Moose
zone
I 4 2 2 45 16 1 a 66 18 84
II 1 2 43 19 3 1 68 26 94
III a 2 160 73 11 4 246 99 345
IV 5
Total 3 6 248 108 15 5 380 143 523
1
~l
.1
.\
.;~
'I
I
1
2
3
4
5
I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III =Montana Creek to
Yentna River and IV =Yentna River to Cook Inlet.
1m =small antlered males,mostly yearlings,probably some two-year old males;
Ad =males with large antlers.
W/O =females without young,W/l females with one young;W/2 females with 2 young.The
W/O category includes males which have shed their antlers;this was prevalent by
mid-December.
In this survey,7 moose were observed on Indian River 200 m up from the Susitna River
and 8 moose were observed on Portage Creek 800 m up from the Susitna River;neither group
was included in the tal ley for that respective zone but this note may indicate that
more moose are moving toward the Susitna River •
Snow conditions in this zone insufficient for observing moose •
27
-
-
-
-
-
-
_.
Table 10.Sex,age composition and zone of location for moose observed on the 20 and 24 January
aerial census of the Susitna River from Devil Canyon to Cook Inlet,Alaska,1983.
Census #12
River Males 2 Females3 Lone Total
1 Ad 1m W/O WIl W/2 calves Ads Calves Moose
zone
I 4 0 0 21 13 3 0 37 19 56
II 0 0 40 8 2 0 50 12 62
III 0 1 146 77 8 4 232 97 329
IV 5
Total 0 1 207 98 13 4 319 128 447
Notes from the previous survey (5 January 1983)indicated that a group of 7 moose were
observed on Indian River 200 m upstream from the Susitna River.On the 20 January 1983
census,a group of 7 moose were observed on the Susitna River 2.4 kID upsteam from
Indian River.I presume this group of moose was the same individuals observed on 5
January 1983.
1m =small antlered males,mostly yearlings,probably some two-year old males;
Ad =males with large antlers.
W!O =females without young,W!l females with one young;W!2 females with 2 young.The
W!O category includes males which have shed their antlers;this was prevalent by
mid-December.
1
2
3
4
I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III
Yentna River and IV =Yentna River to Cook Inlet.
Montana Creek to
,~
5
On 20 January 1983,well defined moose trails were observed along the tops of ridges
which parallel the steep-walled section of the Susitna River between the Devil Canyon
dam site and Indian River.It appeared that there had been a general movement of
moose paralleling the river,and it was also apparent,in some locations that moose had
attempted to descend to the river bottom but had to retreat due to steepness of the
canyon's side walls.
Snow conditions in this zone inadequate for observing moose.
28
Table ll.Sex,age composition and zone of location for moose observed on the 7 and 9 February
aerial census of the Susitna River from Devil Canyon to Cook Inlet,Alaska,1983.
Census #13
River Males 2 Females3 Lone Total
1 Ad 1m wlO W/l W/2 calves Ads Calves Moose
zone
I 0 0 8 6 2 0 16 10 26
II 0 0 25 8 1 0 34 10 44
III 0 1 107 63 4 5 175 76 251
IV 4 0 0 118 42 1 1 161 45 206
Total D 1 258 119 8 6 386 141 527
1 I =Devil Canyon tq Talkeetna,II =Talkeetna to Montana Creek,III
Yentna River and IV =Yentna River to Cook Inlet.
Montana Creek to
2
3
4
1m =small antlered males,mostly yearlings,probably some two-year old males;
Ad =males with large antlers.
W/D =females without young,W/l females with one young;W/2 females with 2 young.The
W/D category may also include males which have shed their antlers;this is prevalent by
mid-December.
Some snow and frost on trees,but overall condition excellent for observing moose in
this zone.
'"""
-
Data gathered during the winter of 1982-83 indicate that the
greatest number of moose (934)were counted on the 20-22 December
1982 census.The greatest total number of moose counted in zones
I-IV,during this winter,were 84,94,460 and 412,respectivelYi
an aggregate total of 1050 different moose.
Relatively early snowfall in the winter of 1982-83,enabled a
census (No.7)to be conducted on 29 October and 6 November 1982.
Due to the earliness of this census and the promptness with it
was conducted after the snowfall (probably before non-resident
moose could move into the wintering area),I believe that the
resul ts are indicative of the numbers of moose which are rela-
tively resident to floodplain habitats and seldom travel far from
these areas during their annual cycle.The relative scarcity of
snowfall after December and the melting of that which had fallen
earlier in the winter were associated with a decrease in numbers
of moose observed on censuses conducted after the 20-22 December
1982 census.This early decrease in numbers of moose in flood-·
plain habitats is apparently in contrast to the much later peak
in numbers of moose observed during the winter of 1981-82 on the
winter of 1982-83 would most probably stimulate moose to return
I,
to winter floodplain habitats.Peak numbers of moose observed on
1 and 2 March census.Of course,addi tional snowfall in the
any single census conducted in 1981-82 (369 moose)were less than
one half the number of moose observed on a single census thus far
during the winter of 1982-83 (934 moose).
30
A summary of the per-e;entage of calf moose observed wi thin each
zone for each census is presented in Table 12.These data exhi-
bi t variation in percent of calves observed between zones and
also over time (between censuses)within a particular year.
Zones I and IV appeared to contain lower percentages of calf
moose than zones I I and I I I.No obvious seasonal change in per-
cent of calf moose observed was noted over time.One would
~-
expect a decrease in the percent of calf moose within populations
due to mortality but such theoretical changes may have been
obscured by differential movement behaviors of sex-age categories
wi thin each subpopulation and/or difficulties in distinguishing
calves from adults.
By mid-January,calf moose appear large and are sometimes diffi-
cuI t to distinguish from adult moose,and from that time on
calves may be found at considerably greater distances from their
parent,a behavior that contributes to the difficulty in asses-
sing relative size of moose and in assigning them to an age
class.
Casual observations during censuses lead me to believe that there
is at least one area within zone III which always appears to con-
I
I
tain a disproportionately larger number of female .moose with
~,
calves than other areas.This observation and its biological
significance will be investigated and tested in a future report,
after more data are gathered and analyzed.
31
Table 12.Percent of calves observed on each of 13 censuses for moose in floodplain habitat
along 4 zones of the Susitna River between Devil Canyon and Cook Inlet,Alaska
j 1981-83.
]
I 1~I No.Date River zone (n)Census totalcensus
I I!II!IV
1 9 and 10 Dec 1981 22 (36)31 (16)31 (147)28 (123)29 (322)
2 28 Dec 81,4 Jan 1982 22 (18)26 (19)26 (191)28 (96)26 (324)
3 2 and 6 Feb 1982 0 (8)20 (5)25 (134)21 (92)23 (239)
4 1 and 2 Mar 1982 0 (7)24 (17)16 (236)20 (107)17 (369)
5 23 and 24 Mar 1982 20 (25)36 (25)20 (166)20 (41)22 (257)
6 12 April 1982 14'(7)17 (18)32 (57)27 (82)
7 29 OCt,6 Nov 1982 22 (14)25 (4)32 (60)29 (89)29 (171)
8 10 and 18 Nov 1982 18 (57)36 (28)25 (232)26 (159)25 (476)
9 1,2 and 6 Dec 1982 17 (76)24 (46)31 (292)18 (412)23 (826)
10 20-22 Dec 1982 20 (76)34 (86)28 (460)21 (312)25 (934)
11 5 and 6 Jan 1983 21 (84)28 (94)29 (345)27 (523)
12 20 and 24 Jan 1983 34 (56)19 (62)29 (329)29 (447)
13 7 and 9 Feb 1983 38 (26)23 (44)30 (251)22 (206)27 (527)
1 I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III =Montana Creek to Yentna River
and IV =Yentna River to Cook Inlet.
....
32
Relati ve value of winter range to moose'-is often expressed in
terms of the density of moose it supports during the winter
period.Very rough approximations of the quantity of floodplain
habi tat surveyed for moose during each census was obtained by
making visual estimates from 1:63,360 scale USGS topographic maps
(Table 13).These data along with values from Tables 7-9 yielded
maximum estimates of 1.4,2.1,2.6 and 4.0 moose per km 2 of sur-
face habitat for river zones I-IV,respectively_Since approxi-
mately 38 to 52 percent of the surface area within a zone may be
underlain by frozen portions of the river and does not support
growth of forage or cover vegetation,densities per unit of
"useful"habitat would be considerably higher.
Casual observations during floodplain censuses indicate apparent
differences between densities of moose observed on the Delta
Islands and on Bell Island (see Fig.1).Both islanded areas are
extensive but Bell Island apparently contains habitat more favor-
able for moose as it appears to support significantly greater
numbers of wintering moose.These casual observations and their
biological significance will be in~estigatedmore fully in a sub-
sequent report when additional data are available and analyzed.
These sorts of data will be extremely useful when information on
I
characteristics of ideal moose winter range and biot~c potential
of various habitats are needed to adequately assess mitigation
options.
33
.....
~!
-
~,
:~
Table 13.Surface area (km2 )of floodplain habitat types in four geographical zones of the
Susitna River between Devil Canyon and Cook Inlet,Alaska.
Terrestrial
Habitat type
Aquatic
Total
River 1zone
I II III IV
28 2 23 104 65
31 21 70 39
59 44 174 104
I =Devil Canyon to Talkeetna,II =Talkeetna to Montana Creek,III =Montana Creek
to Yentna River and IV =Yentna River to Cook Inlet.
Values for surface area derived from visual estimates of habitat types illustrated
on 1:63,360 sca~e USGS Topographic maps.
2
1
34
AFFINITIES FOR RIPARIAN HABITATS
Before one can knowledgeably assess impacts of the proposed
Susi tna Hydroelectric project on subpopulations of moose down-
stream from Devi 1 Canyon,it must be known how and when those
respective subpopulations of moose utilize Susitna River flood-
plain habitats.To knowledgeably predict potential impacts,one
must also be cognizant.of the annual (between year)variation
which may be expected in those patterns of use so behavioral pat-
terns for those subpopulations may be adequately "bounded".
Data obtained from radio-collared moose and presented in Tables
12 and 13 and Tables 14 and 15 summarize informatio~available on
timing and frequency of use of riparian habitats and on variation
in affinities for those habitats,respectively.
Data gathered from individual moose north of Talkeetna indicated
for 2 consecutive years that the greatest affinity for use of
riparian habitats in that region occurred during May and June
(Table 14).Since radio~collared moose throughout ~he study
area calved between mid-May and mid-June,riparian habitats must
be important to this subpopulation of moose for production and/or
survival of newly born young.Particular factors involved in
this association have not yet been identified but might be rela-
ted to presence of early growing nutritious foods (LeResche and
Davis 1973)and/or relative absence of predators (Stringham 1974
and Ballard et al.1980).Apparent "unattractiveness"of ripar-
ian habitats from January through April may in part be related to
the relatively mild winters of 1980-81 and 1981-82.
35
~,
Table 14.Timing and frequency of use of Susitna River riparian habitats by individual radio
collared female moose,between Talkeetna and Devil Canyon,Alaska 1981-1982.
1981 1982
Individual Mar.May Jul.Sep.Nov.Jan.Mar.May Jul.Sep.
and and and and and and alld and and and
Apr.a Jun.Aug.OCt.Dec.Feb.Apr.Jun.Aug.Aug.
29 1/7 b 4/7 0/7 1/7 0/5 0/5 0/5 3/6 0/3 0/2
42 0/6 0/7 0/7 0/7 0/5 0/5 0/5 1/6 0/3 0/2
63 0/6 2/7 0/7 0/7 0/5 0/5 0/5 0/6 0/3 0/3
68 0/6 5/7 0/7 0/7 0/5 0/5 0/5 3/6 0/3 0/1
69 0/6 0/7 0/7 0/7 0/5 0/5 0/5 0/6 0/3 0/1
73 0/6 3/7 0/7 0/7 0/5 0/5 0/5 1/6 1/3 c 0/2
74 0/6 1/7 0/7 1/7 1/5 0/5 0/5 2/5 d
80 0/6 3/4 e
81 0/5 317 0/7 0/7 0/5 0/5 0/5 1/6 0/2 0/2
No.individuals
relocated in
riparian 1/9
habitat/Total
individuals
7/9 0/8 2/8 1/8 0/8 0/8 6/8 1/7 0/7
.....
-
a
b
c
d
e
Number of radio relocations in riparian habitat/total number of observations during
respective time period.
Riparian habitat observation on 28 April.
Riparian habitat observation on 8 July.
Individual observed dead in Susitna River south of Talkeetna on 16 July.
Individual captured south of Talkeetna but moved north of Talkeetna and was found
silted and dead on bank of Susitna River;died approximately 6 July •
36
Data presented in Table 15 indicate that for 2 consecutive years,
in riparian areas and apparently utilized those habitats through-
habitats in February and March and proceeded to depart from them
moose radio-collared downstream from Talkeetna sought riparian
This behavior was most typical of individualsouttheyear.
during April.However,some individuals in this region remained
habi tats in December,were most frequently relocated in those """
which were found to range in and near extensive islanded areas in
the Susitna River,i.e.,the Delta Islands and the Big/Bell
Island complexes.Available data indicated that roughly 16 per-
cent (4 of 22 and 5 of 35 moose radio-collared in 1981 and 1982,
respectively)of this subpopulation of moose which utilized
riparian habitats in winter were found to be "resident"to those
areas throughout the year.During more severe winter conditions
one would probably expect that riparian habitats are shared
amongst a higher proportion of "non resident"moose.
Though the greatest potential impacts to the upstream subpopu-
lation may occur in May and June and to the downstream subpopula-
tions from December through March,there is a portion of moose in
the latter population which utilize riparian habitats throughout
the year and will be vulnerable to impacts during any seasonal
1
period.
Data exhibiting variation in affinities for riparian habitats and
in behavioral patterns for both individuals and subpopulations of
37
Table 15.Dates indicating chronology of departure from Susitna River riparian
habitat for female and male moose radio-collared in habitats down-
stream from Talkeetna,1980-82.
Date Females Males
Riparian a Non-riparian Riparian Non-riparian
1980
Apr.3 b 3
May ND c ND ND ND
;~Jun.3 3
Jul.3 3
Aug.3 3
Sep.3 3
Oct.3 2
Nov.3 2
Dec.3 3
1981
Jan.3 0 2
Feb.d ND ND ND
Mar.15 3 4 2
Apr.7 11 1 5
May 2 16 0 6
Jun.4 14 0 6
Jul.5 13 1 5
Aug.3 15 0 6
Sep.4 14 1 4
Oct.3 14 1 4
Nov.2 15 0 5
Dec.8 9 1 4
1982
Jan.9 8 0 5
Feb.e 18 6 7 4
Mar.f 17 10 5 6
Apr.12 15 5 6
May 5 22 3 7
Jun.5 22 3 6
Jul.3 24 1 7
Aug.4 23 1,7
Sep.3 23 2 6
a Riparian =individuals relocated at least once during respective,time
period within outmost banks of the Susitna River;Non-riparian =individual
f"'O'1 not relocated during respective time period within outmost banks,of the
Susitna River.I
b 3 females and 3 males radio-collared in riparian habitats.
r c ND =no data collected during time ~eriod.
d 16 females and 4 males radio-collared in riparian habitats.
e 7 females and 6 males radio-collare~in riparian habitats.
f 3 females radio-collared in riparian habitats.
38
moose are presented in Table 16.These data demonstrate consid-
erable differences in movement patterns betHeen upstream and -
dOHnstream subpopulations of moose.Those subpopulations of
moose dOHnstream from Talkeetna spent a considerable amount of
"time at distances greater than 5 miles from the Susi tna River,
whereas their counterparts north of Talkeetna Here seldom relo-
cated farther than 5 miles from the Susitna River.Males in both
subpopulations,usually ranged farther than females from the
riparian habitats.These data also exhibit noteable differences
between behavioral patterns of individual moose within a sUbpopu-
lation.
These data illustrate that impacts to subpopulations of moose
Hhich utilize Susitna River riparian habitats primarily as Hinter
range,may be realized in areas quite remote from the banks of·
the river and the source of the impact.Impacts most remote from
the Susitna River will probably be realized in male moose of each
subpopulation.
Data presented in Table 15 show how far iridi vidual moose were
relocated from their ini tial capture site in consecutive years.
In most cases,individual moose were consistent betwe~n years in
i
the distance they moved away from their _capture si te or winter
range;larger di fferences were·apparent between individuals.
39
-
Table 16.Variation in and general affinities for floodplain habitats of the Susitna
River exhibited by moose radio-collared and relocated periodically during
complete yearly periods.
Percent of relocations at distances {mil
from floodplain (F)
Area Sex 2
Population 1
Treat3ment
No.
Moose 4 Re10castions
F.0-1 1-3 3-5 5-10 10-15 15-20 20+
.i....
Upstream
Downstream
Ws
Es
All
F
M
F
F
M
Max
Min
Total
Max
Min
Total
Max
Min
Total
Max
Min
Total
Max
Min
Total
1
1
8
1
1
3
1
1
13
1
1
5
1
1
6
39
39
310
40
38
103
41
41
524
38
38
194
41
38
211
15
o
7
3
o
1
95
2
33
3o
3
7
o
6
64
13
44
30
34
40
5
o
8
3
3
3
34
o
10
21
26
37
45
34
39
o
5
16
5
3
12
59
o
13
o
54
9
23
3
10
o
o
1
26
13
21
o
o
6
o
8
2
o
29
11
o
5
19
63
34
40
o
3
23
o
oo
o
89
21
o
21
12
o
26
10
o
o 6
T
o
o
1
o
26
9
o 0
34 37
18 13
1
2
3
4
5
6
Upstream =north of Talkeetna.Downstream =south of Talkeetna.Ws =Westside
of Susitna River.Es =Eastside of Susitna River.
F =female.M =male.
Max =data for individual moose which exhibited maximum affinity for floodplain
habitats.Min =similar but for minimum affinity.Total =affinities calculated
for respective population.
Moose =moose yrs.may represent 2 years of study for 1 moose.
Relocations =data collected for entire calendar years.sampling intensity
relatively similar throughout year.
T =0 0.5 percent.
40
I.".
These data may generally be interpreted to show how far individ-
ual moose may travel in an annual cycle in order to arrive at or
to return to sui table and traditional winter range.Some moose
may never range far from Susitna River riparian habitats but yet
they may still have to travel substantial distances between sea-
sonal ranges;i.e.,ranges of individual moose are not always
spatially arranged perpendicular to the Susitna River,some may
be al"most parallel to riparian habi tats (re:Male No.92).
41
MOVEMENTS OF RADIO-COLLARED MOOSE
To knowledgeably assess impacts of hydroelectric development of
the Susitna River on moose,one must;1)delineate subpopula-
tions of moose which are ecologically affiliated with habitats
potentially subject to alteration;2)determine in what way,
when and how many moose from those subpopulations utilize flood-
plain habitats;3)determine how and where potential impacts to
those subpopulations will ultimately be realized,and 4)propose
various mitigation plans and determine their overall positive
effects on the moose resource.These sorts of data can only be
provided by studying movements of individual moose within those
subpopulations .and determining the ecological significance of
those movements.
Data presented in Fig.4 illustrate the extent of movements for
moose captured and radio-collared along the Susitna River between
Devil Canyon and Cook Inlet.These data may be used indicate the
minimum spatial extent that impacts incurred by moose while util-
izing Susi tna River riparian habitats will-be realized.These
data show that impacts to moose on the Susi tna River floodplain
between Devil Canyon and Cook Inlet may ultimately become obvious
j
in areas as far west as Beluga Lake,Little Peters.Hills,the
Chuli tna River,as far north as Hurricane i or as far east as
Chunilna Creek,Sheep River,the head waters of Sheep Creek,
Pi ttman and Big Lake;an area covering approximately 8938 km 2
•
42
Figure 4.Polygon encompa.alng 2178 relocation pointe for 10 moo••
radio-collared 17 April,1980,29 mooee radio-collared 10-12 March,
1~81 and 17 mOOee radio-collared 28 February -10 March.1982 along
the Sualtna River between Cevlt Canyon and Cook Inlet,Alaaka and monitored
through 20 October,1982.,(Inc'uelve area =8938 kmZ )
43
-
Likewise,positive impacts.of mitigation efforts undertaken in
riparian habitats may be realized throughout this same area.It
is apparent that impacts to moose from hydroelectric development
are very likely to ultimately be realized in areas quite distant
from the Susi tna River.
Figs.5 and 6 illustrate points of relocation for female and male
radio-collared moose,respectively.These data indicate that
.~
!~li".
extent and spatial relationships of impacts will,in part,depend
on the sex of affected moose.Though samples for males were con-
siderably smaller than for females,particularly north of Tal-
keetna,the males as a whole appeared to range more widely.Im-
pacts to male moose will most probably be realized farther from
riparian habi tats tlian for females .
Changes in environmental conditions along the Susitna River as a
result of.hydroelectric development may directly affect produc-
tivity of some subpopulations of moose or productivity of subpop-
ulations of moose which calve in areas distant from riparian
habitats may be secondarily affected thro~gh elimination of
female moose or through alteration of their nutritive condition.
Likewise,mitigation measures which improve the calving environ-
I
I
ment or winter range condition in riparian habitats m~y increase
productivi ty of moose sUbpopulations in those particular areas.
Consequently,enhancement of environments for moose in riparian
areas which result in greater productivi ty,may subsequently
place added stress on environments used by thosesubpopulations
44
-
Figure 5.Radlo-relocatlona (1871)for 40 femal.moose captured and
radio-collared along the Susltna River between Devil Canyon and Cook
Inlet.Alaska.1980-82.
~,
-
-
...
o
t::;
+++
+ ++ +.......
++
45
-
....
.-
Figure 8.Radio-relocations (582)for 15 male moose captured and
radio-collared along the Su.ltna River between Devil Canyon and
Cook Inlet.Alaska.1980-82.
..
~.
-
-
-
•
-".
•••••
ov
~.
/.,.
\
\
•
I ..
,.
47
•
•
•...•...•."• •
..•
..6
-
!".,"
Figure 7.Ll)catlons (314)where 40 female moose captured and
radio-collared along the Sualtna·River between Devil Canyon and
Cook Inlet.Alaaka.were radio-relocated during the calving period
(10 May -17 June).1980-82..
48
-
-
-
6-.:...&.!f f Il!I"l
,,;,('r.....#.~•
6-)
.-•..~•••·If-'~.....i.«,~!
\))\~-r:::J
Figure 8.Location.(447}where 12 male and 38 female moose
captured and radio-collared along the Sualtna River between Devil
.Canyon and Cook Inlet..Alaska.were radio-relocated during the
summer period (1 July -31 Auguat).1880-82.
49
,.,..,
•
•
•
o
t:;
•
•
Flgur.9.Locatlona (239)wh.r.11 mal.and ·38 femal.moo ••
captur.d and radio-collared along the Suaitna River b.tw.en D.vll
Canyon and Cook Inlet.Alaaka.were radio-relocated during the
month of September (-hunting aeaaon·).1980-82.
50
Data presented in Figs.10 and 11 illustrate locations,where
female and male moose,respectively,which wintered in Susi tna
River riparian habitats were subsequently relocated during the
rutting period.Some moose of each sex spent the rut period in
or near their winter range and others rutted up to 40 km from
electric development on moose which winter on the Susitna River,
may likely affect rut~ing acti vi ties in these areas.
their winter range along the Susitna River.Impacts of hydro-
Data gathered from moose captured and radio-collared along the
Susi tna River in late winter and relocated during subsequent
winter periods (1 January -28 February)indicated that not all
individual moose returned to riparian habitats (Fig.12).Other
data collected indicated individual and annual variation in the
timing of arrival on Susitna River riparian winter range.Though
most moose arrive on winter range by January,some arrive later
and some may winter in entirely different and distant areas in
.....
subsequent winters.These data support the contention that ~,
winter river censuses may underestimate the numbers of different
moose which seek winter range in riparian habitats.Information
collected from behavior of radio-collared moose may be used in
conjunction with data from river censuses to adjust for under-
I
estimates in the numbers of different moose \'lhich ma,y be depen-
dent on floodplain habi tats for \'linter range.
51
-
-
i
!
"*'
•
.....
-
;-v-'
•t \•(I.-6 )~•••/"'"'!
>I'
I ~,1'\
\
Figure 10.Location.(204)where 38 female moo.e captured and
radlo-coUar-ed along the Susltna River betweenOev/l Canyon and
Cook Inlet.Alaska.were radio-relocated during the rut period
(14 September -31 October).1980-82.
52
....-.~-.."
-
-
-
-
-
-
."
I
17
1/
)
.;
)
o
(;
•
FIgure 11.Locatlone (89)where 11 male mooee captured and
radio-collared along the Sueltna AI"er between De,,11 Canyon and
Cook Inlet.Alaeka.were radio-relocated during the rut period
(14 September -31 October).1980-82.
.....
53
-
oo
I!
(ty
(<.6.~
d~].~~
(7""\/-IF~If)~
'"')0\I
\---"-•)
Figur.12.Locations (184)wh.re 7 male and 40 female mooee
captured and radio-collared along the Sueltna River between
Devil Canyon and Cook Inlet.Alaaka.were radio-relocated during
the winter period (1 January -28 February).1980-82.
54
Information on size,shape and spatial arrangement of ranges for -
to explore and/or exploit few areas that are not in their normal
male and female moose is useful in assessing how individuals uti-
range,they would be slow to realize the presence of new winter
-
-
-
An assessment of annual
Since previous data col-
Likewise,with information on
sizes and spatial arrangement of ranges,the aeral influence of
lize available resources and habitat;
lected indicate that most moose are very patterned and consistent
in their use of winter range along the Susitna River and appear
variation in range size for individual moose may be used to pre-
habitat alterations may be predicted.
range,which may be created as a mitigation measure,unless _it
were wi thin their normal range.
annual variation in climatic condi tions .
and to provide information on the utility of studying movements
dict annual variation in use of Susi tna River riparian habitats
-Such data alsoofindividualsoverseveralconsecutiveyears.
document adjustments moose make to their range in response to
Data presented in Table 17 provide information on variation in
,
i
i
.~
.,,
range size between individuals wi thin sex classes,between sex
classes and between consecutive years of study within individuals
and sex classes.Range sizes varied greatly betwe~n individuals ~
and within sex classes,males tended to maintain rang~s of larger
size than females and both sexes were found to utilize additional
range in the second year they were studied.-
55
Table 17.Array of·maximum distances (km)between the capture site and a relocation site,for
individual (Id)female (F)and male (M)moose,radio-collared in different areas
along the Susitna River,Alaska and monitored between 0 and 3 annual cycles,1980-82.
Annual cycle 2
Area 1
T to DC
CI to F
Sex
F
M
F
M
Id
68
29
73
81
63
69
42
74
66
92
39
100
97
7lc
80
96
94
40
41
87
93
58b
37
90
85
19
62
57
79
64
56
82
45
59
88
26
23
22
95
90
99
44
60
84
65
91
27
1
5
6
6
7
8
11
28
40
15
32
5
10
13
18
20
21
25
27
33
37
41
49
7
7
10
17
17
21
24
24
26
37
38
41
43
18
25
44
5
8
18
45
17
17
45
16
43
•
2
6
3
9
4
6
12
4
30
13
29
5
4
8
18
17
21
23
23
26
33
37
41
42
19
22
46
19
35
38
16
42
3
29
15
21
49
13
38
1
2
T =Talkeetna,DC =Devil Canyon and CI =Cook Inlet.
Last annual eycle for each individual typically spans the 28 February - 4 April to OctobE
interval.Previous eycle(s)for each individual typically spans an entire annual eyelets
from 28 February - 4 April of one year to similar dates the following year.
56
Wi thin sex classes,comparisons between individual female and
male moose,studied for less than 1 year,exhibited over 25 (No.
indicate that there are large individual differences in the size
between individual female and male moose studied longer than 1
and-less than 2 years,indicated individual differences in range
-
These data
Similar comparisons
size up to and over 35 and 4 fold,respectively.
pectively,in sizes of ranges utilized.
39 vs.No 58b)and 30 fold (No.95 VB.No.44)differences,res-
of annual ranges.
Other data presented in Table 18 indicate that some individual
moose increased the size of range used the first year by over 25
percent in the second year of study (Nos.23,73,82,84,91 and
92).Though sample sizes for individuals studied more than 2
years were small,some individuals continued to exhibit a similar -
but much smaller increase in annual range size.
Figs.13 and 14 graphically illustrate annual variation in size·-and shape of ranges used by individual moose studied 1 year 6
months and 2 year 5 months ,respectively.
Figs.15, 16,and 17 illustrate relative size,shape and spatial
I
arrangement for a sample of ranges from radio-collare~moose·mon-
-
annual alterations in range size for individuals are available in
i tared _throughout the study.Detailed data on range size and
-Table 16.These data exhibit a wide spectrum in method of use of
Susi tna River habitats by moose:from individual s with ranges
~-
57 -
Table 18.Variation in calculated range size within and between individual (Id).-female (F)and male (M)radio-collared in two areas along themoose
Susitna River,Alaska and monitored different periods of time,1980-82.
Period Range Percent change in range size 4
Area 2
monitored No.size Inter-Increase Inter-Increase
No.annutl Sex Id (months)reloca-arraY3 section year 1 to 2 section year (1+2)
cycles tions (km2 )year 1 &2 year (1+2)3 to 3
Less than 1 CI to T F 39 9 19 10
7la 11 36 16
7lc 8 18 53
97 9 19 57
96 9 19 75
94 9 19 75
40 9 18 96
100 9 19 98
80 4 10 178
87 9 18 242
7lb 7 23 243
58b 8 17 280
M 95 9 19 14
99 9 19 87
44 8 17 480
1 to 2 F 90 20 56 23 36 0.6
85 20 57 39 56 2.4
37 20 56 43 39 1.2
57 20 56 69 59 3.9
19 19 54 81 23 1.6
62 19 54 134 37 10
82 20 55 176 39 39 •
64 19 55 188 61 0.4
45 20 56 193 11 0.7
59 20 55 195 60 3.0
79 18 53 217 39 0
56 18 53 228 25 <0.0
88 20 57 317 57 0.2
~
M 60 18 54 143 26 0.9
84 19 55 430 52 30
65 20 55 579 58 5.8
T to DC F 29 19 53 20 36 0.2
68 19 53 21 46 13
63 20 54 30 32 0
69 19 52 42 48 6.9
81 19 51 44 38 5.6
73 19 53 64 37 51
42 20 53 99 21 2.6
74 16 47 721 2.2 1.5
M 66 20 54 137 48 19
2 to 3 CI to T F 26 30 70 217 54 10 6.7 0
23 30 76 268 92 34 51 1.9
22 30 76 745 76 2.5 46 2.5
M 91 31 78 153 67 22 34 0
T to DC 92 31 73 483 41 27 48 8.7
CI to T 27 30 74 650 26 5.6 15 0
1 No.of annual cycles studied from date of capture.
2 CI =Cook Inlet,T =Talkeetna and DC =Devil Canyon.
3 Area of non-overlapping,geometric union of ranges calculated for each annual cycle or part of.
4 Intersection years 1 and 2 =percent of year 1 range used in year 2,Increase year 1 to
2 =percent of range used only in year 2,Intersection years (1+2)and 3 =percent year (1+2)
range used in year 3.Increase years (1+2)to 3 =percent range used only in year 3.
58
#59
1 cm =3.3 km -
-
-
-
-
-
#88
1 cm =3.4 km
,'.....,
I ............,,,
I
I
/'
/
/,,
/,"I,,
I
I
#45
1 cm =2.7 km
FIgure 13.VarIation In .Ize and shape.of range.determined,for 4 female
moo.e captured and radio-collared along the SusUna RIver downstream
from De.,11 Canyon and monitored from March 1981 through September 1982.
Polygon.encompass radIo-relocation·points for consecutl.,e annual periods
commencing from date of capture through 1981-82 ()and 1982-83
(----)annual period..-.
-
59
"l-,.-J --J l-,,··..1 ]
0'\a
female #22
1 em =6.3 km
mah~#27'
1 ern ,=3.3 km
,,7
\-,I,'"~
\'"\/
male #92
1 em =3.7 km
I
..I
Figure 14.Variation In .Ize and .hape of ran.e.determined for 4 moo.e capture.d .nd.
radio-collared along'the Su.lt"a River down.tream from Devil Canyon and monitored from
April 1980 through September 1882.(Polygon.encompa ••radio-relocation pointe for
consecutive annual period.commencing from da"of capture thro"gh 1980-81 (),
1981-82 ()and 1982-83 (----)annual period ••
..,
-
...
.-o
I::;
Flgure.15.Shape and spatial relatlona hips for range.of 8 male
moose captured and radio-collared along the Susltna River between
Devil Canyon and Cook Inlet.Alaska and monitored during 1980-82.
(Range.d~plcted with polygons encompassing points of Individual
radio-relocations.)
61
o
(;
Figure 18.Shape and spatial relationships for ranges of 10 female
moo.e captured and radio-collared along the Susltna River between
Oe.,11 Canyon and Cook inlet.Alaska and monitored during 1980"'82.,
(Ranges depicted with polygon.encompassing points of Individual
radlo-reloca tlons.)
62
Figure 17.Shape and spatial relationship.for range.of 12 female
and 1 male (#91)moos.captured and radio-collared along the SusUna
River between 0 •..,11 Canyon and Coo.k Inlet.Alaska and monitored during.
1980-82.(Range.depleted with polygons encompassing polnta of
Indl"ldual radio-relocation ••)
-
-
-
-
-
that center on riparian habitat,to those individuals with ranges
that "traverse"riparian habitats and to those individuals with
ranges that merely abutt riparian habi tats.
64
PRODUCTIVITY AND SURVIVAL OF YOUNG
Productivity of female animals and survival of their newly born
young are commonly used as indicators to assess the general well
being of animal populations.These same parameters may be used:
1)to assess both·subtle and more obvious impacts of proposed
Susitna Hydroelectric development on subpopulations of moosei 2)
to evaluate the results of enhancement procedures undertaken as
mitigation options and/or 3)to provide options for consideration
in mitigation,i.e.,improvement of calving or rearing habitats
or reduction of predation on calves.
-
Data gathered from the radio-collared samples of moose,on timing
of calving,number of calves produced and survival of those
calves are presented in Table 19.
individual female moose in Appendix A.
These data are itemized by -
-
Data on productivity and and survival of calves in spring 1980 l!IIl1I,
were obtained from a very small sample of moose and will not be
trea ted alone.
-Data provided by 27 radio-collared moose which were observed
i
i
during the spring and summer of 1981,indicate that 4 had 2
calves,18 had 1 calf and 5 had no calves.Data from 23 of these
same moose indicate that 13 had 2 calves,2 had 1 calf and 1 had
no calves.The sample of 11 moose radio-collared in 1981 indi-
cate that 7 had two calves,4 had 1 calf and 0 had no calves.
-
65
J 1 -J ]],1 i J J 1 J i 1 1 1 J i
Table 19.Monthly summaries of female radio-collared moose and associated calves observed along the Susitna River
during radio-tracking flights,1980-82.'.
--
1980 1981 1982
Observation A M J J A S 0 N D J F M A M'J J A s 0 N D J F M A M J J A S 0 N D
Total females 6 4 3 3 3 3 3 3 3 3 3 27 27 27 27 26 26 25 25 25 24 24 32 35 35 35 34 34 33 33 33 33 33
Females with
2 1 1 1 0 0 0 0 0 0 0 17 8 13 21 21 21 20 20 20 19 17 21 ;L8 18 30 24 22 22 21 20 15calves28
Females with
twins 1 1 1 1 0 0 0 0 0 0 0 2 0 1 4 2 0 0 0 0 0 0 1 1 1 14 11 7 7 6
-6 6 1
Total calves 3 2 2 2 0 0 0 0 0 0 .0 19 8 14 25 23 21 20 20 19 19 19 22 19 19 44 39 31 29 28 27 26 16
•Ca1ves/100
females 50 50 67 67 0 0 0 0 0 0 0 70 30 52 93 88 81 80 80 76 79 71 69 54 54 125 115 91 88 85 82 79 48
1 Calf moose observed with an individual female on non-sequential months were assumed to be present and alive
0'1 during the interim months when they were not actually observed.Calf moose that were not observed sometime
0'1 during May -December 1982 may be observed during flights in 1983.
Overall,these data indicate that in 1981 81 percent of 27 radio-
collared female moose produced young,15 percent of them produced
2 calves and an average of 1.2 calves were produced by every
female with young.Similar data for 1982,indicate that 97 per-
cent of the 34 radio-collared females observed in the spring and
summer produced young,59 per cent of those produced 2 calves and
an average of 1.6 calves were produced by the 33 females observed
wi th young.
Two possible explanations for the observed differences between
productivity calculated in 1981 and 1982,where 22 and 3 percent
of the females were not observed with young and 15 and 59 percent
of the females were observed with single or twin calves,respec-
-
tively,in those respective years are the following:1)favor-
able environmental conditions in 1982 enabled females to attain
and maintain a higher level of nutritive conditions then in 1981
2)environmental conditions were similar in both years but
females normally do not produce twins in consecutive years and/or
3)more intensive searches for young during radio-relocation
surveys.The second possibility implies that producti vi ty in
1980 was at a level commensurate with that in 1982.
Since the high level of twin production in 1982 occurred in 2
different samples totaling 35 moose:1)those captured in 1980
and 1981 north of the Yentna River and 2)those captured in 1982
south of the Yentna River it was probably not an artifact of
sample size or local variation.
67
If the observations of twinning were explained by the second con-
tention,I would expect that few of the females which produced
.-twins in 1982 will do so in 1983.
Environmental conditions may have been worse prior to parturition
in 1981 than in 1982,since in 1982 26 of 33 productive females
were observed with neonatal young in May whereas in 1981 only 10
of 24 prodl;tctive females were observed with neonatal young in
May.FavdlJable environmenta±condi ti'ons may improve physical
~,
condition of pregnant females and result .in earlier dates of par-
turition and higher levels of productivity.Likewise,peak num-
bers of calves in the population occurred in June of 1981 and in
May of 1982.
The percentage of calves in the 1981 and 1982 populations
declined sharply through July in 1981 and through June in 1982.
By August in 1981,84 percent of the calves produced were still
alive,16 percent had disappeared;by November 76 percent were
still alive.In 1982,only 70 percent of the calves produced
were alive by August;by November 63 percent of the 125 young
produced were known to still be alive.By November,the ratio of
'''''''calves per 100 cows was 76 and 79 for 1981 and 1982,respec-
-
"""I
r",
tive1y.Of course,by that time winter could also be accountable
for the between year variation in calf survival.
Causes for the relatively rapid rate of loss during the first two
months after the peak of parturition are not known.Newly born
68
moose calves succumb for many reasons,but a prominent cause for
neonatal death of moose calves on the Kenai Peninsula (Schwartz
and Franzmann 1981)and in the Nelchina Basin (Ballard et el.
1980)is black and brown bear predation,respectively.As indi-
cated in a previous report (Modafferi 1982),circumstances in the
lower Susitna River Valley areas appear conducive to predation by
black bears.
Predation bh moose -calves cou~d become -mcfre prominent in riparian
habitats immediately downstream from Devil Canyon,should bears
displaced by post-project impoundment water levels,colonize
areas downstream from the Devi 1 Canyon damsi te.
69
~,
!
f--
PUBLI C USE OF MOOSE RESOURCE
Impacts on the moose resource from'development of the Susi tna
Hydroelectric project in areas downstream from Devil Canyon will
secondarily impact both consumptive and non-consumptive users of
that local resource.An important non-consumptive use of moose
in this area is recognized but in the absence of adequate quanti-
tive data iJt 'dill not be considered specifical'ly in the present
,,
report.Though radio-collarea moose ranged into portions of sub-
uni ts 16B and 14A,'information on resource use in these areas
will not be compiled until more complete data are available to
better delineate those respective subpopulations of moose.Fig.
9 illustrate where moose which were captured and radio-collared
on the floodplain of the Susitna River were distributed during
September;the usual time of open hunting seasons.
Data on consumptive use of the moose resource in areas frequented
by 3 identified subpopulations of moose are presented in Tables
20,21,22,23,and 24.These tables summarize information on
number and residency of users,quantity and type of effort,num-
bers and sex of·moose killed and provide data on numbers of
applicants for lottery permi t hunts.
One prominent feature of these data is that access to and use of
the resource,in both subunits 16A and"14B,is available to users
through multiple types of transportation.It is not uncommon for
70
•
Table 20.Transportation type,effort (mandays),number of moose killed,number of hunters and
their residence for participants in the 1979-80,1980-81 and 1981-82 open hunting
seasons in Game Management Unit 14B,Alaska.
71
....
Table 21.Sex and number of moose killed and number of applicants for limited entry,
lottery type hunts in Game Management Unit 148 for the 1979-80,1980-81
and 1981-82 hunting seasons.
Year 1979-80 1980-81 1981-82
Hunt No.1 911 913 911 913 911 913
No.applicants 667 60112 686 210 720 413
No.permits 100 50 100 50 100 50
No.moose ~illed 22 43 18 30 21 42
No.hulls _233 ··4 -.-11 0 17
No.cows 42 13 19 21 25
....
r
1
2
3
No.911 is a fall season cow moose hunt and No.913 is a winter season
antlerless moose hunt.Data abstracted from Alaska Department of Fish
and Game files.
In 1979-80,hunt No.913 was announced as a separate drawing hunt open
for application by any person that had not killed a moose during the
regular open hunting season.
Data combined for hunt No.911 and 913.
•
72
Table 22.Transportation type,effort (mandays),number of moose killed,number of hunters
and their residence for participants in the 1979-80,1980-81 and 1981-82 open
hunting seasons in Game Management Unit 16A,Alaska.
~:
Year
No.hunters1
No.residents
No.moose killed
I
1979-80
585
549
128
1980-81
946
912
179
1981-82
983
955
189
~,
Transportation type
(No.participants:Effort)
Aircraft
Horse
Boat
Motorbike
Snowmachine
Of froad vehicle
Highway vehicle
Unspecified
Total effort
57:245 77:330 88:483
2:3 2:5 0:0
85:468 127:665 126:790
4:17 5:12 6:30
1:12 1:5 0:0
94:604 132:757 162:1021
240:1204 456:2610 395:2141
102:544 146:803 206:1068
3097 5187 5533
1 Data abstracted from the Alaska De~artment of Fish and Game harvest
ticket master file.
73
i
!_.
-
-
Table 23.Number of moose killed and applicants for limited entry lottery type cow
permit (Hunt No.908)hunts in Game Management Unit 16A for the 1979-80,
1980-81 and 1981-82 hunting seasons •
•
74
Table 24.Transportation type,effort (mandays),number of moose killed,number of hunters
and their residence for participants in the 1979-80,1980-81 and 1981-82 open
hunting seasons in Game Management Unit 13E,Alaska.
~.
Year
No.hunters1
No.residents
No.moose killed
I
Transportation type
(No.parti~ipants:Effort)
1979-80
29
24
14
1980-81
20
19
5
1981-82
28
26
10
Aircraft
Horse
Boat
Motorbike
Snowmachine
Offroad vehicle
Highway vehicle
Unspecified
Total effort
1:5 2:5 1:5
3:18 1:10 0
0 1:1 2:10
0 0 2:5
0 0 0
20:115 4:17 8:78
3:15 2:20 2:7
2:28 10:50 13:105
29:181 20:103 28:210
1 Data abstracted from the Alaska Department of Fish and Game harvest ticket master file.
These data represent the following code areas:Wiggle Creek,Susitna River (Wiggle
Creek to Chase),Whiskers Creek,Chase (Alaska Railroad,ARR),Susitna River (Chase to
Lane),Lane Creek,Lane (ARR),Blair Lake,McKenzie Creek,Susitna River (Lane to
Curry),Deadhorse Creek,Troublesome Creek,Curry (ARR),Susitna River (Curry to Gold
Creek),Sherman (ARR),Gold Creek (Chunilna Hills),Gold Creek (ARR),Canyon Creek,
Devil Canyon,Portage Creek,Thoroughfare Creek,Canyon (ARR),Indian River,Chulitna
Pass,Summit Lake (south of Hurricane),Pass Creek (Chulitna)and Susitna River (Sherman
north and south of).
75
i·~,.
~
wildlife resources in some'areas to be commonly accessible
through only one or two types of transportation.But the moose
resource in subunits 16A and 14B is readily ·accessible to many
users through highway vehicles,off-road vehicles,aircraft and
boat,and therefore provides recreational opportunities for many
"subgroups"of users,each associated with a type of access.The
moose resource in these subunits is truly a multiple use resource
utilized bYia multiple of user groups.
That portion of 13E utilized by the subpopulation of moose north
of Talkeetna,attracted considerably fewer hunters and appeared
not to be as readily accessible as subpopulations in subunits 16A
and 14B.The apparent unattractiveness of subunit 13E to hunters
may in part be attributed to the fact that nearly half of that
area lies in Denali State Park,an area closed to the discharge
state Park was opened to the discharge of firearms,I suspect the
of firearms since the early 1970's.
•
If,in the future,Denali
area would attract a considerable number of moose hunters.
Access to area is available by foot,highway vehicle and off road
vehicle from the Parks Highway,by float and wheel equipped air-
craft,by boat via the Susi tna River and by train along the
Alaska Railroad.
I suspect the average "type"of person utilizing the 13E subpop-
ulation of 'moose differs from that utilizing the moose resource
in subunits 16A and 14B.Resources in subunits 16A and 14B are
76
utilized by local residents but these areas also provide recre-
ational and hunting opportunities for a large number of people
resident to Anchorage and adjacent metropolitan areas;the latter
no doubt predominate in overall use of the local resource.
However,the apparent small user base in subunit 13E should not
diminish the relative value of that local moose resource.In the
late 1960'siand early 1970 l s property along the Susitna River in
the Curry,:,Lane and Chase areas was made---available to the public
through a State of Alaska homesite land disposal program.I sus-
pect that people who took advantage of this program and obtained
that land,endeavored a subsistence type lifestyle,of which
~oose and moose meat probably playa dominant role.Needless to
say,ready availability of moose in that area may be a very inte-
gral part in the lives of local residents.
Future state land disposals are planned in the Gold Creek and.
Indian River areas.I believe one of the major attractions to
people for remote parcels of land is the potential for subsis-
tence type lifestyles,and that the quality of these parcels of
land is closely related to the local abundance of fish and wild-
life resources,as moose.
It is well documented that substantial numbers of moose occur in
subpopulations ~hich are normally resident to relatively inacces-
sible areas east of the Susitna River in the western foothills of
the Talkeetna Mountains (subupi ts 14A and B).
77
Most moose in
these subpopulations remain in the foothill regions during mild
winters,but in moderate to severe winters,it is said that they
exodus to "secondary"wi.nter range in lowland areas along the
Susi tna River,around transportation rights of way and other
~
sites where climax vegetation has been disturbed and more palat-
able winter browse of early successional species is available
(Rausch 1958).Under these conditions numerous moose are killed
by collisiops with trains or highway vehicles,jeopardizing pub-
lic safety I and causing cons:kl.erable monetary loss in equipment
damages.
During the severe winter of 1955-56,224 moose were killed by the
Alaska Railroad train in a 70 mile stretch from Willow (milepost
160)to Sunshine (milepost 230)(Rausch 1958).It has been rum-
ored that nearly 20 moose have been killed in one night from a
single train traveling between Anchorage and Fairbanks.Simi-
larly,during the winter of 1970-71,in subunit 14A and B,it was
documented that over 100 moose were killed by vehicles in highway
rights of way (Didrickson 1973).
These problems are 2-foldi not only is browse in these areas an
f"""attractant to moose but the rights of way in train and highway
areas are also plowed clear of snow and afford moose easy travel.
Once in these plowed areas,moose do not readily leave them for
areas where snow is considerably deeper even when confronted with
trains or vehicles and therefore many are killed.
-
78
The subunit 14B lottery type permit moose hunt is implemented to
serve 2 main functions:1)to harvest moose from a subpopulation
that is relatively inaccessible during other times of·the year
and 2)to reduce the number of moose near highway and train
rights of way for improved public safety.In accomplishing those
objectives,additional demands for recreational opportunities and
consumptive use of the moose resource are,in part,sati sfied.
79
i~
MORTALITY
Capture Related
Three of the 59 moose immobilized,field handled and aroused,
subsequently died or·were II euthanasized",wi thin 3 days,in the
immediate v~cinity of their initial capture site.
In two of i these in-stances,nrortali tyap·peared to be proximately
related to injuries sustained from slipping on exposed,glare ice
of the frozen Susi tna River .Extensive areas of exposed glare
ice is a common phenomena of the Susitna River between the Yentna
River and Cook Inlet,where strong prevailing north and east
winds blow snow off frozen sections of the River and polish the
ice smooth wi th abrasive action of snow crystals and silt.
One moose was field processed and aroused in a normal manner but
when the assisting helicopter approached to pick up personnel it
initiated a running response in the moose.The moose fell twice
while trying to flee across the ice,once in a "spread eagle ll
state and the other time onto a hip joint.The field crew left
the moose to collect itself and recooperate in the absence of
further disturbance.A reconnaissance trip to the area 3 days
later revealed that the moose had died on the ice not far from
where it was last observed.
80
The other moose which fell on the-ice and apparently injured
itself,had previously been immobilized and handled,and it typi-
cally departed the river bed to a forested area after being
aroused.However,a brief time later,it was observed in the
-
~I
same-general area in a prone position on glare ice.It was
assumed to still be partly under anesthesia and was left to
recover on its own.Three days later,the moose was found alive
in the same location;it was then euthanasized.
One mortality was perhaps totally attributed to field 1:landling
technique.Subsequent to capture procedures,it was determined
that an individual had not traveled far from its capture site.A
reconnaissance trip,3 days after capture revealed the individual
was in the same location as when it was field processed.It had
rotated itself 180°,cold move its head and neck,exhibited no
-
sign of injury,but apparently could not get itself up.
individual was euthanasized.
Non-Hunting Mortali ty -Case Histories
This
A male moose captured and radio-collared 24 February 1982 and
rated at that time in condition class 5 (7 =average)was later
found dead 2.5 km from its capture site.In March,the individ-
ual was radio-relocated 800 m from the capture site and on
4 April it was reloc~ted and observed alive in the immediate
\
I
~
vicini ty of where it Wf..S later found dead.Subsequent radio-
relocations to the same area revealed no movement by the moose,
81
.~
~w indicated the collar may have been shed and lead to field inspec-
tion of the site.At the site,it was observed that remains of
the moose had been scattered around the general area by bears.
The actual cause of death could not be determined but since death
occurred 2.5 km from the capture site and month later it was pro-
bably not related to immobilization and handling procedures .
.....
A female mobse,No.80,captu"red 11 March 1981 about 5 km south
of Talkeetna was relocated about 13km"south of that site in mid
April and 20 km north of the capture site on 7 May.Three sub-
sequent radio-relocations indicated the moose had not moved from
that site and suggested the collar had been shed.Field inspec-
tion of the area revealed the moose intact,dead,lying on the
ri verbank,i tIs hide dry and leathery in texture and covered
with silt.It is probable that the moose went to this riparian
area to calve,as is common for moose north of TalJ<eetna,but
fell through overflow or got caught in an ice jam or high water
during breakup where it died and remained in a relatively pre-
served state.
Female moose No.71a,a relatively sedentary individual,which
only once was relocated more than 5 km from its capture site and
spent the majority of its time within 1 km of the Susitna River,
was determined to have died between 19 and 29 January 1982.
Field investigation on 10 February reveal the moose was laying on
glare ice with splayed hind legs.The moose had been "picked on"
by predators,the collar had been partly cut with a knife and no
82
signs of gunshot ...munds were observed.Personnel investigating
the scene reasoned that the moose most likely slipped on the
glare ice,where it lay,split its pelvis and or injured its hip
joint,could not move and died from exposure and/or starvation;
scavangers appeared after death.One would not normally expect a
relatively sedentary individual,in very fami liar surroundings,
to succumb to an accidental death.
Apparently my experiences with moose injUred on glare ice during
capture procedures w~re not so out of the ordinary,and are prob-
ably not an uncommon natural occurrence.The pilot of the fixed-
wing plane used during capture procedures,who also piloted on
all river censuses,commented that in his travels during the
winter of 1981-82,he had observed about a half dozen dead moose
lying on glare ice of the Yentna,Skwentna and Kahiltna Rivers.
Circumstances at each site,lead him to believe that those moose,
too,died as a r~sult of injuries'sustained from slips and falls
on glare ice.
Female moose No.74,captured in March 1981 north of Talkeetna
near Chase,traveled widely during the 16 months she was moni-
tored,before being observed underwater and dead in a log jam of
a Susitna River side channel on 16 June 1982.This individual
remained quite sedentary most of the year and except during the
late May to mid-June period seldom ranged farther than 8 km from
her capture site.However,between 21 May and 22 June 1981,she
traveled 40 km north to the Chulitna River,south 70 km to the
83
~.
~'
t-.
'~
middle Fork of Montana Creek,then north 36 km to an area on the
Chulitna River only 7.7 km west of her capture site,where she
resumed using fami liar range.She remained in that "home H area
until being-radio-relocated on 26 May,29 km to the south near a
side channel of the Susitna River.It was wi thin 1 km of thi s
site,that she was observed dead under water near the log jam.I
presume,somehow she had drowned in the River,perhaps after get-
ting carrikd into the log j am while attempting to.cross the
!----.-~..river;though she may well have been killed further upstream in
another manner and was carried by river currents into the log
jam.
The long excursions from the relatively confined Hhome H range
near the capture site were probably to areas where she intended
to bear calves.Several other radio-collared females (No.22,23
and 42)were known to make long excursions immediately prior to
calving.It is interesting to note that this individual was com-
monly observed but was only seen with a calf when she was initi-
ally captured.It seems reasonable,that moose which travel fre-
quently or over great distances would have a higher probability
of encountering "chance circumstances H which could result in
Haccidental I!death or loss of calves.
Female moose No.79,captured and radio-collared 10 March 1981
between Goose Creek and Sheep Creek Slough,behaved more like
female moose (No.22,23 and 26)captured in 1980 than her coun-
terparts captured in 1981;except for her calving activities
84
which took place northeast of Trapper Lake,she usually ranged
east of the Susitna River near Sheep Creek,about 17 km northeast
of her capture site.In 1982,she departed the Trapper Lake area
wi th 1 calf and returned to her summer and fall range in the
Sheep Creek area.On 23 September,the transmitted signal from
this individual's radio-collar came from a 5 m diameter disturbed
area in whLch a brown bear was lying.The bear was obviously at
the site wh~re this female moose had been killed.It is possible
that the b'ear -killed the moose,but since several hunter tent
camps were al so observed in the vicinity,one camp was only 1
mile away,it is equaily possible that the moose was killed by a
hunter during the open female moose season.The hunter may have
thought his activities were illegal when he saw the radio collar,
salvaged the meat but left the collar at the kill site.The
brown bear may have located and consumed the remains of the moose
which were located near the neglected radio-collar.Fresh snow
soon covered,the site and precluded recovery efforts but next
spring I will helicopter to the site and attempt to reconstruct
the exact circumstances of death.
Hunting Mortali ty -Case Hi stories
Four of the radio-collared moose,3 males and 1 female,have been
legally killed by hunters during the open hunting season.Brief
case histories and details of their movements which lead to those
confrontations wi 11 follow.
85
Male moose No.93,captured and radio-collared in April 1980,was
killed by a hunter 5 months later about 7 kIn southwest of the
capture si te .Thi s individual commonly ranged near the Parks
Highway just north of the Sunshine Bridge;an area traversed by
many hunters.
Female moose No.71b,captured and radio-collared in March 1981,
. !traveled w~th a calf to the Deshka River area west of Amber Lake,
-
41 km northwest of her capture site and was subsequently killed
""'"on the bank of Moose Creek by a hunter "floating"the creek.
This moose and her calf were frequently relocated along Moose
Creek south of its confluence with Ninemile Creek.Moose hunters
commonly II float"down streams in subunit 16A during the open
hunting season.
Male moose.No.92,captured and radio-collared in Apri 1 1980
along the Susitna River near Sherman,was killed by a hunter in
September 1982,near Curry.This particular male commonly ranged
along the south side of the Susitna River from McKenzie Creek to
area north and to be near Devil Canyon by July or August and then
return along the south bank of the Susitna River to its wintering
ages.Each year this individual would travel from that wintering
Though
It was during this return trip in theareanearLaneCreek.
third consecutive year,that he was killed by a hunter.
""'"Devi 1 Canyon and wintered in the Lane or Chuni Ina Creek drain-
this individual traveled extensively,he appeared to move between
86
3 distinct and seasonally used areas:a summer area near Devil
Canyon,a winter area in Lane Creek and a spring/fall area
between Lane and Curry.
Male moose No.84,captured and radio-collared in March 1981 just
north of the Delta Islands was killed about 7 km from that site
by a hunte.r in September 1982.This individual was commonly
relocated ~long the Deshka River,Trapper Creek and the Susitna
Riveri all 'popular"hunting areas,but "he'did travel about 38 km
south west of the capture site to the Pittman area between
February and April of 1982i a movement not detected in March or
April of 1981.
Quantified By Sex,Subunit and Study Area
Data on mortality of individual radio-collared moose are summar-
ized for sex and subunit occupied during open hunting season
(Table 25).Because,these data represent incomplete years and
more than 1 year for most individuals,hunting mortality is
related to the number of hunting seasons each individual was
exposed to and non-hunting mortality is related to the number of
months each individual was monitored.Though these values may
roughly approximate overall average mortality regimes for respec-
tive populations of moosei one must realize that hunting mortal-
ity rates for individual moose as No.84 and 90,which commonly
ranged near readily accessible and popular hunting areas,as the
Deshka and Susitna Rivers and Parks Highway,respectively,would
87
Table 25.:Hunting (K)and non-hunting ·CD)mortality for individual (Id)male (M)
and female CF)moose captured and radio-collared along the Susitna
River between Devil Canyon and Cook Inlet and resident in Alaska Game
Management Subunits 13E,16B,16A,14A and 14B while monitored 1980-82.
13E 16B 16A 14A 14B
Sex ld Sex ld Hs Mths Sex Id Hs Mths Sex ld Hs Mths Sex ld Hs Mths
Total 2 4 (lK)84'2K";9
M 66
92
1
3K
20
'51
M 44
95
Total 2
1
1
2
8
9
17 -
M 60
65
2
2
18
20
M 27 3 30
...-90 1K 6
91 3 31
99 1 9
Total 6 9(2K)103
""'"'
Total 9
2 19
1 11M
2 29
30
23 3 30
26 3 30
F 22 3
79 1 IBM
Total 4 10 108(lM)
9
9
9
9
F 39
41
96
100
20
20
20
18
20
20
20
9
7K
20
20
9
19
2
2
2
2
2
2
1
2
1
2
1
2
2
88
90
94
85
87
82
71a
7lb
F 19
37
45
56
57
59
62
64
9
8
8
8
9
42
1
1
1
1
1
5
93
97
71c
F 40
58b
Total 5
19
19
20
20
19
19
16M
5M
19
156 (2M)
74
80
81
29
42
63
68
69
73
F
"""'
Total 16 28 271 (lK and 1M)
1
2
Hs =number of hunting seasons individual was exposed to,(-)=hunting season not open for females.
Mths =number of months individual was observed and susceptible to non-hunting types of mortality.Capture
and handling related mortalities not included.
88
vary greatly from that of individual No.65 which ranged "near
Amber Lake and Peters Creek,a less accessible and more remote
area.Sample sizes for all but subunit 16A are extremely small
and may lead to erroneous conclusions.
In view of aforementioned shortcomings,these data indicate that
25,a,22 qnd a percent of the male moose which wintered on the
Susi tna Ri vbr in an average winter and vlere exposed to a hunting
season in;'subunits 13K,16B;16A and --14B,respectively,were
killed by hunters.Similarly,the average male moose in subunits
16B and 14B,probably survives at least 2 open hunting seasons.
Overall,the data imply that 17 percent (3 males ki lIed in 18
moose-seasons of vulnerability)of the male moose that wintered
on the Susitna River and are exposed to a hunting season are pro-
bably killed by hunters.
Subuni ts 16A and B have open hunting seasons for female moose.
In the former subunit,a limited number of permits are issued by
lottery drawing.In the later subunit,the season is open to all
hunters.None of the 5 female radio-collared moose which uti 1-
ized subunit 16B during the open hunting season were killed by
hunters.One of 16 female radio-collared moose vulnerable to
hunting for an aggregate total of 28 seasons in subunit 16A was
killed by a hunter.These data imply that less than 4 percent of
the female moose which range on the Susitna River in an average
winter and are available to hunters during open season in subunit
16A,are killed.
89
-
None of 2,1 of 4 , 0 of 6 and 0 of 1 male radio-collared moose
observed for a cumulative total of 51,26,103,36 and 108
.-
months~respectively,in subunits 13E,16B,16A and 14B,respec-
tively,died from non-capture related,non-hunting mortality.
This individual (moose No.76),as previously reported,was dis-
covered dead on Bell Island 3 months after its capture.It is
possible that this moose was killed by a brown bear.This island
is located i less than 10 kIn from Mt.Susi tna,an area in which
,,
brown bears -commonly occur.Because oT the proximity of this
area to Mt.Susitna and Little Mt.Susitna,brown bears are pro-
bably more abundant in riparian habitats along the Susitna River
south of the Yentna River than from the Yentna to Talkeetna.
Considering data collected in all subunits,only this 1 of 17
radio-collared males monitored over 324 months was known to die
from non-hunting (predation or accidental)mortality.-
Data gathered from female radio-collared moose indicate that 2 of
9,0 of 5,1 of 16,0 of 4 and 1 of 4 individuals monitored for
~156,42,271,36 and 108 cumulative months,respectively,in sub-
units l3E,16B,l6A,14A and 14B,respectively,died from non-
hunting causes of mortality.Most probable causes of their death
were brown bear predation,2 drownings'and 1 injury from slipping
on ice.The cumulative total for all subunits indicates that a
"natural ll mortality occurred in 4 of 38 radio-collared female
moose individually studied for various lengths of time.In
total,these 38 moose provided 613 months of observation and
yielded 1 death for every 153 moose-months.
90
/"l"Hlo.
Data obtained from this radio-collared sample of moose indicate
that under present management schemes male moose throughout the
area studied are about 9 times as likely to be killed by hunters
as females (3 male moose:18 moose-seasons vs.1 female moose:55
moose-seasons)and that females are more than 2 times as likely
as males (4:613 moose-months vs.1:324 moose-months,respec-
tively)to die from non-hunting causes of mortali ty.
, I
91
~I
POPULATION PHENOMENA
Forty-six moose captured and radio-collared late in the winters
of 1979-80,1980-81 and 1981-82 along the Susi tna River from
Portage Creek to Cook Inlet,a linear river distance of approxi-
_mately 215 km,had by 20 October 1982 ranged over more than 8900
km 2 of habitat adjacent to the Susitna River.Apparently,ripar-
ian habitat~along the Susitn~River serve as winter range for
,
moose which'are very widely -eli stributed--at other times of the
~:.
year.It is not uncommon for several populations of moose to
share a common winter range (LeResche 1974 and Van Ballenberghe
1977).
Considering general patterns of movement documented for radio-
collared moose,large geographical uni ts where radio-collared
moose were never relocated and areas along the Susi tna River
where data have yet to be collected,Modafferi (1982)hypothe-
sized the existence of 9 geographical units which contain moose
that utilize the Susitna River riparian habitat at some time
"""during an II average"year (Fig.18).Moose wi thin each geograph-
tats;2)have peculiarities in.their life history and/or environ--ical uni t:1)behave similarly in their use of riparian habi-
ment which distinguish them from moose in other units and/or 3)
may not necessarily visi t those riparian habi tats every year.
92
o
NORTH
I"'i
10,0
i
G
-
.j....
~\-
Figure 18.Spatial relationships for hypot.hetlcal sub populations of moose In the Susltna
River watershed between Devils Canyon and Cook Inlet.Alaska (from Modafferi 1982).
subpopulation di stinction
the behavioral variation-
...
It may be appropriate to consider all moose which "linter along
the Susitna River as a single population unit but local differen-
ces in movement patterns and environmental conditions documented
in this study indicate that particular life history strategies
must also vary to accommodate specific local environmental con-
di tions.Since patterns of movement for individual moose are
extremely traditional (Van Ballenberghe 1977)and may be subse-
quently "leArned by offspring (Gasaway et 01.1980),they can
rapidly become characteristic and fixed for individuals in
specific local areas through processes of natural selection,if
they prove to·be of survival value and individual fitness is
increased.It therefore appears that
is most appropriate to account for
observed in moose along the Susi tna River .
Sampling in different years,at different locations and at dif-
ferent times in the winter has yielded representatives from
several different subpopulations of moose along the Susitna
River.The sample of moose captured and radio-collared in 1980
conformed to characteristics of subpopulation D (Montana Creek/
Sheep Creek).Moose characterizing subpopulations A (Upper
Susitna ~iver),C (Deshka River/Trapper Lake)and F (Delta Island
complex)were captured and radio-collared in the 1981 sample of
moose .Moose captured in the 1982 sample generally conformed to
specifications for G (Yentna River/Mt.Susitna)and I (Big
Island/Bell Island complex)subpopulations.This sampling scheme
94
has failed to capture moose representing subpopulations B
(Talkeetna River/Sheep River)and E (Kashwitna River/Willow
Creek).This observation along with the fact that few represen-
tatives from subpopulation H have been captured indicates that
most moose which use Susi tna River ripari an habitats in a 11 aver-
age l1 winter are resident to areas west of the Susitna River.The
possibility.also exists that moose from subpopulations Band E do
use ripariJn habitats in II average II winters but depart before
,,..
March when samples of moose were captured.
Since representatives from subpopulation G did not appear to come
from very great distances down the Yentna or Kahiltna Rivers,I
suspect that riparian habitats in those respective river drain-
ages provide adequate winter range for locally resident moose.
However,to the contrary,moose from the southern part of area G
(south of Mt.Susitna),even in a relatively mild winter,
traveled extensive distances to winter on the Susi tna River.
Apparently,sufficient or adequate winter range is not locally·
available in the latter area.
It is not known,from which subpopulation(s)the large numbers of
moose counted in the 20,21 and 22 December river census origin-
~,
-
ated.They may have come from wi thin subpopulations that are
represented.in I!average ll winters,they may have originated from
subpopulations farther to the west than subpopulations C and G
and/or they may have been moose from subpopulations D,E and H
\-thich are resident in areas to the east.
95
In any event,data
~,
-
-
I~
,....,
-
.....
--
-
gathered from subsequent river censuses indicated that they only
remained in floodplain habi tats for a short period of time.It
is unfortunate,that more than two times the number of moose used
Susitna River riparian habitats in the winter of 1982-83 as did
in the winter of 1981-82 and their origin remains unknown.
96
HABITAT REHABILITATION
Because major mitigation strategies,to compensate for impacts of
the proposed Susitna River hydroelectric development on subpopu-
lations of moose,will be through maintenance,replacement and/or
creation of new habitats to augment those presently used by moose
for vlinter.range,periodic censuses,paralleling the timing of
rrivercensuses,were conducted on 6 sites where vegetative com-
plexes had been alte-red by man~-
Conditions,causes and timing of disturbances to these specific
si tes are not presently known but could probably readi ly be
researched,if necessary.
All sites monitored were immediately adjacent to floodplain habi-
tats of the Susi tna River except for the Kashwi tna Lake si te,
which was located about 1.5 km east of the SusitnaRiver.
Because of such close proximity of these sites to floodplain
habi tats,they may possibly compete with or compliment winter
range presently available to and used by moose wintering along
the Susi tna River.
Though close to floodplain habitats,numbers of moose counted in
these disturbed sites,were not included in talleys for river
censuses.However,it seems likely that moose using these sites
are not discrete groups from those using adj acent floodplain
habitats;a flux of individuals between both habitats probably
exists.
97
"'"',
Data presented in Table 26 demonstrate intensive use of some
sites and variability in use between different sites.In part,
variation may be attributable to differences in size of indivi-
dual sites,but it may also be related to factors as plant
species composition,age of plants,proximity to other sites and
location with respect to general movement patterns of subpopula-
I
tions of m6ose.Differences betvleen years in numbers of these
moose using sites are probably'mostly related to snow conditions
and winter severi ty ~Differences in sex composition of moose
observed between areas'(Talkeetna west vs.other sites)appeared
to occur;biological reasoning or significance for these obser-
vations are at present unclear.
I plan to continue study of moose use of these disturbed sites in
the future,as information provided will be necessary for knowl-
edgeably considering mi tigation options.
98
Table 26.Numbers,sEx and age of moose a observed in areas adjacent to the Susitna River
floodplain where vegetation and plant succession have been altered by
activities of man,Alaska 1981-83.-Winter
period
Montana west Montana lIliddle Talkeetna west .
1m Sill FO Fl F2 Lc Tm Lm Sill FO Fl F2 Lc Tm LIn Sill FO Fl F2 Lc Tm
1981-82
2 Dec 15 14 i 6 3 o o 41 -
14 Dec 15 c
o 24
o 13
23
o 25
4
4
7
1
1
1
o
o
o
o
oo0
o 0
1 0
o 0
1 0 "I
o 07
o
2
1
1
o
o
o
o
o
01
o
o
o
o
o
1
2
4
o
9
o 0
o 0 11
o 0
o 0 23
o 0
o 0
2
o
o
o
1
6
2
2
o
o
9
6
3
o
o
o
o
oo
o
o
o
1
4
8
1
o
o
o
1
1
1
o
o
o
o
1
5
1
o
5
2 4
o 14
o 1
o 1
1 7
1 2
8
o
3
o
o
o
6
1 Mar
24 Mar
6 Feb
28 Dec
29 Dec
12 Apr
10 Dec
10 Nov 16
o O·2
o 0 12
o 11
1982-83
29 Oct
6 Nov 7 o 4
10 24
5
9
o
o
1 22
o 68
o
o
3
o
1
1
o
1
8
o
o
1
o 0 o o
1
o
2
1
3
3 2
1 0 o 8
2 Dec 12
6 Dec 7
18 Nov
9 20 10
I,
I
~
9
2 23
o
1 21
1 0
5 2
4 3
7
5
3
2
o
o
o
o
o
1 0 43
2 0 47
1 0 40
o 0 41
1 0 41
2
3
6
5
3
5 21
2 25
3 16
3 15
5 15
6
5
19
17
7
o 69
o 56
1 36
1 41
o 28
1
o
1
1
o
6
4
o
9
4 15
4 19
18 6
1125
4
6
1
5 Jan
22 Dec
21 Dec
1981-82
2 Dec
10 Dec
14 Dec
28 Dec
o o 0 o o o o 5 o 1 o 16
29 Dec
99
Table 26 Continued.
Winter Montana north ~hwitna Lake Montana south
period
Date 1m Sm FO Fl F2 Lc Tm 1m Sm FO Fl F2 Lc Tm 1m Sm FO Fl F2 Lc Tm
6 Feb
1 Mar 0 0 1 0 0 0 1 -0 0 4 1 0 0 6
24 Mar 0 0 0 0 0 0 0 0 0 5 1 0 0 7
12 Apr 0 0 0'0 0 0 0 0 0 1 0 0 0 1-1982-83
29 Oct
6 Nov 0 0 3 0 0 0 3
10 Nov 2 6"4 1 0 0 14
18 Nov 0 0 1 1 0 0 3
2 Dec 0 0 1 0 0 0 1 3 1 6
2 1 0 17
6 Dec 1 0 2 0 0 0 3 3 2 14 1 0 0 21
~21 Dec 0 0 8 0 0 0 8 1 0 12 3 0 0 19
22 Dec 0 0 2 0 0 0 2 1 0 3 3 0 0 10
r"./itI'IlI 5 Jan 0 0 6 0 0 0 6 0 0 17 1 1 0 22
a Lm =males with large antlers;Sm =males with small antlers,mostly yearlings,hrobably
""""males;FO =females without young;Fl =females with one young;F2 =females wit 2 young
Tm =total moose.
b Specific location of areas illustrated in Fig.2.
1""'\C Includes Sm moose too.
100
LIMITATION OF SAMPLES AND SAf1PLING EFFORT
Concern has been expressed about the relationship between subpop-
ulations of moose represented by individuals in the samples cap-
tured for radio-collaring and subpopulations of moose which are
ecologically affiliated with floodplain habitats along the
Susi tna River (Modafferi 1982).
,,
Since the magnitude of use of the Susitna River floodplain habi-
tats by moose as a winter range is related to the amount of snow-
fall and its persistence as ground cover into early spring,the
lack of a severe winter and the occurrence of relatively mi 1d
winters in 1979-80,1980-81,1981-82 and 1982-83 in spite of
record early snowfall in October and November of the latter
vlinter,must be weighed when considering results presented in
thi s report.
Theoretically,moose sampled in late winter of 1979-80,1980-81
and 1981-82 should not be representative of subpopulations of
moose which only seek floodplain habitats during more severe
vlinters.
Circumstantial evidence gathered in the winter of 1982-83 appears
to support this theoretical contention.The largest number of
moose observed in floodplain habitats of the Susitna River
between Cook Inlet and Devil Canyon in the winter of 1981-82
occurred on the 1-2 March 1982 census when 369 moose were
counted.In 1982,following early and heavy snowfall,171 moose
were counted in the same area in late October.-;>-_.
101
-
-
,...
-
-
-
In the same sample area and following continued above average
snowfall 476 moose were observed in mid-November and 826 in early
December.By late December,934 moose were observed utilizing
winter range in floodplain habitats along that same stretch of
the Susitna River.At that time,most all of the moose captured
and radio-collared in previous winters had returned to utilize
winter ranJe in floodplain habitats.Following a relatively dry
and warm December 1982 and January 1983-"many moose had departed
from Susitna River floodplain habitats.Three separate censuses
between January and early February revealed between 450 and 525
moose;about 400 of the moose '.'lhich sought floodplain habitats in
early '.'linter in response to heavy snowfall "promptly"departed
from winter range along the Susitna River when weather conditions
ameliorated.However,despite thi s apparent exodus of nearly
half of the moose,most radio-collared moose remained distributed
in floodplain areas ..These data strongly suggest that a large
portion of the moose which were utilizing floodplain habitats in
December were a behaviorally distinct group (subpopulation?)from
those which were captured in samples from the previous years.
It may be hypothesized that those additional moose which utilized
floodplain habitats in December 1982 were:1)a behaviorally
distance sub-set of individuals from within subpopulations A,C,
D and/or G already delineated (Fig.18,and Modafferi 1982),2)
individuals from subpopulations (B,E and/or H)not yet represen-
ted in the radio-collared samples and/or 3)individuals from sub--
populations resident to areas more remote than those hypotheti-
cally delineated.
102
This circumstantial evidence demonstrates several facts about
relationships between present samples.of moose,sampling methods
and subpopulations which uti lize Susi tna River floodplain habi-
tats:1)samples presently being monitored do not adequately
represent all sUbpopulations,2)the importance of maintaining
independent_and parallel sampling schemes (radio-collaring and
river censukes)which when integrated provide information neither
method could have provided alone and 3)idditional information is
needed to predict.annual variation which might be expected in
utilization of floodplain habi tats.
More intensive and site specific sampling of moose must be con-
ducted on sites where vegetative succession has been altered by
man.Present observations are gross oversimplifications of their
interface with moose ecology.Enumeration of 50 moose on a site
on successive surveys,-provides no indication of individual turn-
over,ie.,whether 50 or 100 different moose used the site.
Knowledge of other ecological factors which might be required by
moose and are provided by peripheral habitats are entirely
unknown.Behavioral (social)interactions which may place den-
sity restrictions below energetic carrying capacity of sites are
not known.Moose appear to congregate at some sites earlier in
the winter than other sites (Montana west vs.Montana middle).
Some sites appear to be more acceptable to cows with calves than
other.si tes (Talkeetna west vs.Montana north).
103
-
......
-
Numbers of male moose providing information on movements and pop-
ulation identi ty throughout the study area are small.
Sample size of moose radio-collared north of Talkeetna,where
post project impacts are expected be be greatest is small.To
represent males in that subpopulation,data are presently_being
collected f~om a single individual.For these reasons,I believe
the sample Isize available for delineation of this subpopulation
of moose is inadequate.
Because of the imperative need to obtain a sample of moose in
floodplain habitats during a severe winter,equipment and fin-
ances should be set aside for sampling acti vi ties (river cen-
suses,carcass counts,additional radio-collaring and monitoring)
during a severe winter.Perhaps a severe winter may be charac-
terized as one when about 1300+moose are observed in floodplain
-habi tats along the Susi tna River .
104
POTENTIAL MAJOR IMPACT ME CHAN I sr<1s:And Associ ated Effects
Altered Seasonal River Flow Patterns and Loss of Annual Variatiori
in River Flow:soil erosion and deposition,inundation,
drought,ice jams,ice scouring (influence through destruc-
tion of vegetation and influence on main channel erosion and
redi stributioh of soi 1),ferti lizing effects -of inorganic
and/or l organic nutrient loads,water or ice surface area,
.....
redi stribution-
-._-
of debris,terrestrial floodplain surface
area,floods,effects on beavers,bears or other subpopula-
tions of moose,composition,distribution and/or abundance
of plant species or plant communities.
Altered Water Temperature:ice fog/fog (physical,physiological,
visual,insolation and insulation);frosting of vegetation;
plant phenology;composition,distribution and/or abundance
of plant species or communi ties;ice scouring;ice jams;
open water in winter.
Alteration of·Habitat:transmission corridors,railway and
vehicle rights of way;project facilities,attractant for
predators and conspecific competitors.
Increased Access:transmission corridors;railway and vehicle
rights of "ltlay;winter boating.
105
Human Encroachment:construction and maintenance employees;hun-
ters;visitors;recreators.
Increased Railway and Vehicular Traffic:
ence wi th movement,direct mortali ty.
disturbance,interfer-
-Impoundment:inundation displaces predators and conspecific com-
petitots.
, I
Altered Turbidity:c?mposition,distribution and/or abundance of
aquatic plant species.
Salt Water Encroachment at Cook Inlet:composition,distribution
and/or abundance of aquatic and riparian plant species.
Altered Ecosystem:secondary and tertiary effects from impacts
on plant and other wildlife species as salmon,beaver,
bears,wolves and other subpopulations of moose.
106
RECOIvWIENDATIONS FOR FUTURE RESEARCH
Until specifics and limits of seasonal and annual variation in
post-project flow regimes and water levels of the Susitna River
are known and secondary responses of plant communities are pro-
jected,it is not possible to assess their subsequent impacts on
subpopulations of moose which are ecologically affiliated with
the Susi tnal River.Before such data are avai lable,I recommend
continuation of a general,broad based---research study of the
ecology of subpopulations of moose which are known to interface
with environments influenced by the Susitna River in its present
,state.
General studies of individual moose and of subpopulation behavior
will always continue to provide data useful for knowledgeably
assessing impacts or predicting responses of moose to any type of
""'",
hydroelectric development on the Susi tna River.As limits of
expected variation in hydraulics and plant communities are fur-
ther refined,research on moose may likewise be directed to
investigate particular impacts in finer detail.At the present
time,it seems inappropriate to become too specific in addressing
potential impacts on moose while disregarding other more general
impacts.
To date,it seems that the extent and magnitude of expected
hydraulic changes and their influence on vegetative communities
107
,
t·"""',
I~
between Talkeetna and Cook Inlet remain uncertain.Until poten-
tial changes are more clearly outlined,general information on
behavior of these subpopulations of moose should definitely not
be discontinued.If at a later date,it is learned that impacts
in this reach of the river will be negligible on moose,data col-
lected on behavior of these subpopulations may at worse form a
basis for assessing and recommending various mitigation options.
Relocation lof radio-collared moose should continue through the
"vlinter of 1983-84.
Periodic winter censuses for moose in floodplain habitats along
the Susitna River should be continued through the winter of 1983-
84.These censuses document variation within and between winters
in the di stribution and intensity of use for all stretches and
habi tat types along the river downstream from Devil Canyon.
Continuation of relocation of radio-collared moose and winter
censuses over a number of years provide information'an annual·
variation in use of Susi tna River riparian habitats.Ideally,
these sorts of data should be collected in a relatively severe
winter.
Since rehabilitation of plant communities to favor moose may be a
prime mitigation option for loss of moose or their habitat,sur-
veys to assess moose use of sites where vege-tative communi ties
have been altered by man,should be continued.To more fully
learn about ecology of those sites and their interface with
108
moose,I strongly recommend that samples of moose be radio-
collared in the Talkeetna West,Montana West,Montana Middle and
Kashwi tna Lake sites which were surveyed during the winters of
1981-82 and 1982-83.
Because large alterations in riparian habitats are expected
between Talkeetna and Devil Canyon,an additional samples of
moose shoul~be radio-collared in that area,to increase the that
sample siz'e'and our data base.I slanded areas appear important
for moose during calying and decreased post project river flows
will possibly eliminate many of the islands.Since behavior pat-
terns for male moose differ greatly from those of females and
presently only one male is providing data from area,efforts
should be made to radio-collar additional males in that subpopu-
lation.
109
~.
....,.
-REFERENCES
Ballard,W.B.,C.L.Gardner and S.D.Miller.
and Workshop.
-
of predators on
Alaska.Proc.N.
459.
summer
Amer.
movements of
Moose Conf.
moose
1980.Influence
in Southcentral
16:338-
""""
Bishop,R.·H.,and R.A.-Rausch.1974.Moose population fluctu-
ations in Alaska,1950-1972.Naturali ste Can.101:559-593.
Chatelain,E.F.1951.\riinter range problems of moose in the
Susitna Valley.Proc.Alaska Sci.Conf·.2:343-347 .
Collins,V'-l.B.1983.Increased or decreased energy for moose?
The Susitna hydroelectric project.Agroborealis 15:42-45.
Didrickson,J.1973.Moose Survey-Inventory Progress Report-·
1971.In D.E.McKnight,ed.Annual Report of Survey-
Inventory Activities,Part I,Moose,Deer and Elk,3,Proj.
V'-1-17-4,Fed.Aid \riildl.Restor.,Ak Dep.Fish and Game,
Juneau.179p.
Gasaway,W.C.,S.D.DuBois and K.L.Brink.1980.Dispersal
of subadult moose from a low density population in Interior
Alaska.Proc.N.Amer.Moose Con£.and Workshop.16:314-
337.
110
LeResche,R.E.1974.Moose migrations in North America.Nat-
urali ste can.101:393-415.
and J.L.Davis.1973.Importance of nonbrovlse
foods to moose on the Kenai Peninsula,Alaska.J.v-lildl.
Manage 37(3):279-287.
i.and R.A.Rausch.------1974.Accuracy and precision of -
aerial 'moose censusing.J.'irHldl.Manage.38:175-182.
~I
Miller,S.and D.Anctil.1981.
Ak Dept.of Fish and Game.
Prog.Rept.Big Game Studies.
Biometrics and data processing.
Susitna Hydroelectric Proj.Ann.
Part I.16pp.
Mm!,
Modafferi,R.D.1982.Moose -Downstream.Ak Dept.Fish and
Game.Susitna Hydroelectric Proj.Phase II Ann.Prog.Rept.
Big Game Studies.Vol.11.114pp.
Rausch.R.A.1958.The problem of railroad-moose conflicts in
the Susitna Valley.Ak Dept.of Fish and Game.Fed.Aid
Wildl.Res.Proj.Final Rept.12(1):1-116.
1959.Some aspects
railbelt moose populations,
Alaska,Fairbanks.81pp.
111
of population dynamics of the
Alaska.M.S.Thesi s.Uni v.
Schwartz,C.C.and A.W.Franzmann.1981.
on moose.Ak Dept.of Fish and Game.
Proj.Prog.Rept.,\'1-17-2.Job 17.34.
Black bear predation
Fed.Aid Wildl.Rest.
Juneau.43pp.
Spencer,D.L.and E.F.Chatel~in.1953.Progress in the
management of the moose of southcentral Alaska.Trans.N.
jl,JU.Wi ldl.Conf.8:539-552 .
1974.Stringham,·S.F.
Naturaliste
can.101:559-593 .
Mo'ther-lnfant-relations in moose.
-Van Ballenberghe,V.
central Alaska.
1977.Migratory behavior of moose in South-
Proc.Inter.Congr.Game Biol.13:103-109.
112
APPENDIX A
Individual visual collar number,radio transmitter and ear tag numbers,date of capture,sex and maternal
status for moose radio-collared in February and March on the Susitna River between the Delta Islands and
Cook Inlet,Alaska,1982.
Capture Sex Maternal status ~
Visual collar Radio 1 date
No.trans.Ear tag
39 10596 -/-2/26/82 F 2 calves ~J!
40 10595 8489/-2/24/82 F o calves
41 6494 16998/-2/24/82 F o calves
44 6503 -/-2/26/82 M i-
58 6412 16855/-3/10/82 F 0 calves
71 6419 16'985/-3/1t}f82 F o calves
75 10594 16944/16986 2/24/82 M ~
76 10592 2/24/82 M
78 10606 -/16701 2/24/82 M
87 10593 -/16937 2/24/82 F 1 calf
93 10590 16721/3/10/82 F 1 calf
94 10597 16984/-2/24/82 F 1 calf
95 10598 -/16710 2/24/82 M
96 10599 16702/-2/24/82 F 1 calf
97 10601 18405/-2/24/82 F 1 calf
98 10603 16987/-2/24/82 M
99 10591 16856/-2/24/82 M
100 16704 16704/-2/24/82 F o calf
1M 2 -/-2/24/82 F o calf
2M 2 -/-2/24/82 F o calf
3M 2 -/-2/24/82 F o calf I,.-.
1 Ear tag =left ear tag/right ear tag.iI
2 ~:
M =Mortality,individual found dead at a later date..'
j
L
l..
113