HomeMy WebLinkAboutAPA4129
This report, Susitna Hydroelectric Project. Final Report, Big Game Studies. Vol. II,
Moose-Upstream, had been distributed erroneously with series statement on label on
cover: Harza-Ebasco Susitna Joint Venture document ; no. 3498.
In addition, the microfiche version was erroneously printed with "Date: 870500" and with
the number 3498 in the header. The number 3498 is really assigned to a report with a
similar title listed as Big Game Studies, Final Report. Volume V, Moose Carrying
Capacity Estimate published in 1987 (it is cited as 59 pages in length in the Susitna
Hydroelectric Project document index). That report is referred to as a progress report in
the preface of this report.
Alaska Library Resources and Information Services has assigned APA no. 4129 to this
document for the Susitna Hydroelectric Project collection.
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SUSITNA IIYDROI!LII:CTRIC PROJI!CT
PIIIAL RBPORT
BIG GAlli! S'l'UDI I!S
VOL. V
110081! CARRYIIIG CAPACITY I!STIJQTE
l!arl P. Becker
Alaaka Depart.ent of Piah and G ...
333 Raapberry Rd.
Anchora9a, Alaaka 99518-1599
MARCH 1988
Between January 1980 and June 1986, the Alaska Power Authority (APA)
r~tracted v i th the c ... Divisioo of the Alaska Depart..ut of Fish and
~ (ADn.G) to provide field data and nc-..datiooa to be uaed for
asseaaiq potential ilopacta and developiq optiooa for aitiaatiq
ilopacta of the propoaed Suaiu.a Hydroelectric Project oo ....,ae,
cariboo, br00111 bear, blaclt bear, Dell sheep, volf, volveriAe, and
belukloa whales. ADn.G vas ooly one of ~~a~~y partici.panta iA this
proar•· Info..atioo oo birds, ... u -ls, furbearers, and
veaetatioo vas collected by the Uaiversity of Alaska and private
c.oosultiq firM .
Foraally, ADn.G'a role vas to collect deta vhicb coald be uaed to
deacri.be the baaelU., pre-project cODditioos . Tbu iAfo..atioo vas
auppl-ted vith data f.--other ADn.G studies. luellA• cooditioos
vera defiAed to iAcluda procuaea vhich aiaht be sufficiently aensi·
tive to either direct or iAdirect project induced iapacta to alter the
dyn•ica of the wildlife populatiou . The nsponsihility of iapact
assu-t and aitiaatioo plADDiDI vas uaiped by APA to several
private c.oosultiq fi..a. ADn.G staff worked closely vitb these
firM, but ooly in an adviaory cepeeity.
Tbe project vas cacelled before the ilopact us•••-nt and aitiaatioo
plUIDiq proceuu vere co.plete. In en effort to preserve tbe
jud&-ts and idees of the authors at tbe teraillatioo of the project,
the scope of this report hu bean expanded to include .. terial
nlatiq to ilopact as•u-t and aitiaetioo planniq. Stat-u do
not necessarily represent the views of tbe APA or ita contractors .
Conjectural stat-u s~t~ are included i D the hope that they
.. y ••rv• .. bypotheau to auide future vork, should the project be
reactivated.
The folloviaa list of reports coapletely cover all of tbe Cae
Divisioo' • contributions to tbe project . It should not be Decessary
for tbe reader to consult the aany proaress reports .
ltodafferi, I . D. 1987 . SusiUia Hydroelectric Project , lia Cae
Studies, Final Report "/ol. I • llonse • Dovnatr••· Alaska Dept .
of Fbh and c ....
Ballard, V. I. end J . S . Vb.itii&D . 1987 . Susitna Hydroelectric
Project, Iii c ... Studies, Final Report, Vol. II • !loose •
UpstreM. Aluka Dept. of Fish and c ....
Becker, E . F . and V. D. Stei1ers . 1987 . Suaitna Hydroelectric
Project, Iii c ... Studies . Final Report, Vol. III • Hoose forac•
bioaasa in the aiddle Susitna River basin, Al .. ta . Alaska Dept .
of Fish end c ....
Becker, E . F . 1987. SusiUia Hydroelectric Project. Iii c ...
Stud!... Final Report . Vol. V • Hoose Carryiq Capacity
Estiaate. Alaska Dept . of Fisb and c ....
~
Pi teller, Jt . V. 1917 . Susitne H}"lroelec:tric: Projec:t, li& G-
Sncliu. FiAal leport. Vol. tv -Caribou. Aluka Dept . of Fish
aDd GMe. S9pp .
Miller, S . D. 1987. Susitlla llydroalec:tric: Projec:t, li& G-Studies ,
Final leport . Vol. VI-llac:k kar and Br<*ll Bear. Alaska Dept.
of Fish aDd G-.
Ballard, V. B., J . S . Vbit8&D, L . D. A•iller, and P . Hua ir •. 1914.
Suit11a Jlydroalac:tric: Projac:t , Bi& G-Stucliu. 1983 Annul
leport. Vol V-Volf. Alaska Dept . of Fish md a-. 44pp.
Ballard, V. B., J . S. Vbit8&D, ADd C . L. Gardller. 1987 . Ec:oloay of
a uploitad -If populatioa iJ>. southc:antral Alaa'ka . Wildlife
!loooarapba No. _ (In press).
Voharine
Vbitaa , J . S . aDd \1 . B. Ballard. 1914 . Susitna Hydroelec:tric;
Projec:t, lia G-Studies . 1983 Annu•l Report . Vol. VII -
1/olvarine. Aluka Dept. of Fish and G-. 2Spp .
DallSb!!l>
Tankersley, N. G. 1914. Sus itna Hydroalec;tric; Projac:t, Bia G-
Sncliu . Filial Report . Vol. VIII -Dall Sheap. Alaska Dept . o£
Fish and G-. 91pp.
Belukha Vbale
Calkilla, D. 1914.
Final Report .
G-. 16pp.
Susitna Hydroelec:tric; Projec:t, Bia G-Studies .
Vol. IX -Belu'kba \/bale . Alas'ka Dept . of Fiah and
TABLE or CONTENTS
LIST or TAB:.ZS
LIST or FIGURES
INTRODUCTION
Moose rora9e Intake Model
ove.rvi-of l!odel Osa9e
Model Input Considerations
Application of the Model to the Suai tna
3
4
5
6
7
8
Hydroelectric Project ••••••••....••••..•••••..• 9
METHODS 9
Area of Interest 9
Duration or. Use 10
Diet 10
RESULTS 11
carryinq capacity estimates 11
1) Moderate Winter -Point Esti mate 11
2) Moderate Winter -Upper 80\
Confidence Limit . . . . . . . . . . . . . . . . . . . . . . . . • • 11
3) Severe Winte.r -Point Estimate 16
4) Severe Winter -Upper 80\
Confidence Limit . . . . . . • . . . . • . . . . . . . • . . . . . • 16
CONCLUSIONS 21
LITERATURE CITED 25
2
LIST OF TABLES
1. CUrrent aooae diet COJIPOBition durinq the
aontha of February, ll&rch, and April • . • . • . . . . 12
2 . Kooae diet co.poaition durinq the aontha of
Februa.ry, Karch and April, with evappinq of
exc••• paper birch tor willow. The aaount
of exc••• birch -• baaed on point eatiaatea
of the aaount of aooae forage available 12
3. Point eatiaate of aooae carryinq capacity
in a .oderate year, by I.poundaent Staqe,
tor the suaitna Hydroelectric Project ....••..• 13
4. Kooae diet COJIPOaition durinq .the aontha
of February, Karch, and April, with
.-pp~ of exceaa paper birch tor willow.
The aaount ot axe••• birch waa
baaed on upper aot confidence liaita or
the aaount of aooae toraqe available •......... 14
5. · Upper confidence eatiaatea of aooae
carryinq capacity in a aoderate year,
by Illpo\ll\daent Staqe,· tor the Suaitna
Hydroelectric Project . • . . . . . . . . . • . • • . . . . . . . . . . 15
6. Point eatiaate of aooae carryinq capacity
in a aevere winter year, by Iapoundaent
Staqe, tor the Suaitna Hydroelectric Project 17
7 . Upper confidence eatiaate or aoo•• carryinq
capacity in a aevere winter, by Iapoundaent
Staqe1 tor the Suaitna Hydroelectric Project 18
8. carryinq capacity eatiaatea aa expr••••d in
aooae denaity, by Iapoundaent staqe, durinq
a aode.rate winter . • . • • • • • • • • • . • . . . . . . . . . . . . . . 19
9. carryinq capacity eatiaatea expreased in
aooae denaity, by Iapoundaent Staqe, durinq
a aevere winter • • • . . . . . . . • . . . . . . . . . . . . . . . . . . . . 20
'
3
4
LIST or FIGOUS
l. Daily Intake ot C.A.G. by Noose 24
nrrRODOCTIOif
construction or the propoaed SU.itna Hydroelectric
Project would reault in the loa• or alteration or exten.iva
area. of 1100ae habitat throuqb a variety of aechani-
(Ballerd et al. 1917). Aa a ~ult, both abort and lO"'J
tar. c:hanqea in 1100H carryin9 capacity would occur. While
there WO\lld be at laaat abort tar. incraa-in carryi"9
capacity in localiaed areaa, a net, lo1'19-tar. decra&H in
potential or the aiddla suaitna Baain to aupport -· b
expected. However, afforta to aanipulata aucc .. aionsl
atagaa or certain plant ~tiaa have &\lcceaafully
incr .. aed 1100ae carryinq capacity in ao.e ar•-of Al-Ita.
conaequently, a kay al..ant in •itigation plana under
conaideration by the Alaaka PoWer Authority ia co.pen.ation
tor decreased 1100aa carrying capacity through burning or
•eebanical -nipulation of plant ccmaunitiaa in the araaa
that vill not be dirturbeci by the pro~ect .
Th .. a factor& ~ it daairabla to aat~ta •oo••
carryinq capacity in the area to be illpacted by the
hydroelectric project in ta~ that 1) could be integrated
vith the considerable body of available 1100•• population
date tor pred.iction of actual population cbangaa, and 2)
could alao be UHd tor .. tabliabing apeeific, •eaaurabla
habitat ~g..ant objective• for planning and evaluating
•itigation actiona. Thia require• an ability to
quantitatively integrate the raquir..anta or the an~l vith
the ability or the habitat to aupply th••• needa .
Paat atrort• to quantitatively apply the concept or
carryinq capacity to the habitat and the population
~;..ant deciaions ~"9 proc••• have -t vith liaited
aucc .. a, becauae or inautriciant undaratanding of the
an~l• raquir..anta. Recut paper• (Moen 1973, Robbins
1973, Wal~ at al. 1977) advocate that carrying capacity
for wild ungulate• be daterained on a nutritional baaia.
C&rryinq capacity •od•l• have recently bean uaed to aat~ta
elk (~ alapbua nalaoni) winter-range carrying capacity
(Hobba at al. 1912), and .ula deer (Qdgcoilaua h,.ionua)
carrying capacity in burned and unburned .c)untain abrub
habl~at (Hobba and svitt, 1915). Thia baaic approach, with
ao.e uy ~ifications, baa been adoptad for •oo•• through
ai.ulation ~ala developed at tha ~ai Kooaa Raaaarch
Canter (HUbbert 1917). Th .. a •od•l• provide a logical,
quantitativa ba.aia tor relating the nutritio.nsl naeda or
•oo•• to the nutriante aupplied by the range and aae.ed
particularly auitad to the naeda or the suaitna
Hydroelectric Project.
Application of thia approach raquiraa certain baaic
aaau.ptiona :
1) carrying capacity ia datinact ·hara aa the nu.bar ot
healthy ani .. l• that can be .. intei.,ad on a unit or land tor
a unit or ti .. without habitat deterioration.
5
2) That the ultiaata factor liaitinq the nu.ber of ~sa in
an area is the supply of nutrients available durinq winter.
3) That when the population ia at or above carryi1t9
capacity, the d.-nd tor nutrients exceeds the supply
available in the apecitic area beinq evaluated (ia that the
aoosa population is capable ot tully utiliainq the nutrients
.. aaured). It is t.portant to keep these aaau.ptiona in
Jlind, because tlu:ouqhout the ranqe ot a population of aoose
there aay be aany areas that contain an abundanca ot
nutrients that, tor a variety ol reasons, such as snow
accu:.ulation, cannot be used by the aooaa . Inclusion of
such areas will yield carryinq capacity astiaataa that are
too hiqh and attaapta to increase toraqa in these areas will
tail to increase carryinq capacity ot the population's ranqa
as a whole ,
Available intoraation indicate that these assuaptions
are reasonable tor lower, put perhaps not tor hiqhar,
elevations in the vicinity ot the Susitna Hydroelectric
Project (8ackar and Staiqars, 1987). In the aiddla susitna
Basin, IIQOsa browsillCJ on willows increased with c:lacraasinq
elevation until the 2300 toot 'alavational laval was reached,
attar which browsinq pressure didn't chanqa with dacraasinq
elevation (Becker and Stalqars 1987). These lower
alevatlonal areas, .. pacially the ones below 2600 t .. t in
elevation, produce lass aoose toraqa than areas at hiqhar
elevations (Becker and steiqera 1987). Ballarc:l at. al
(1917) reported that aoose aova into the 'lfatana Iapounclaant
troa early February to April, this coupl~ .with the data on
aoose brovsinq by elevation, suqgasts that toraqa at hiqhar
elevations aay not be readily available to aoosa durinq the
winter. In addition to the loss of aoosa toraqa due to
beinq restricted to a winter ranqa, the loss of leafy
aatarial further reduces the aaount of toraqa available to
IIOOM durinq the winter. Reneltar a.nd Hudson (1986) reported
that aoose spend aora tiae toraqinq per unit of toraqa in
·the winter, they attributed this to lass toraqa available,
aspac:ially d11e to unavailability of leafy toraqa. Studies
by both Schwartz at al. (1984) and Renakar and Hudson (1985)
found that aoosa toraqa intake is at its lowest durinq the
winter period, with April beinq the month ot lowest intake
(Schwartz at al. 1984). Raneker and Huds~n (1986) and
(Staiqers at al. 1986) found that diqestibility of moose
toraqe obtains its ainiaua value durinq the winter period.
In spite of the reduced demand aoosa have tor toraqa in the
winter, it is felt that it was durinq the wi nter period that
aoosa carryinq capacity was bainq liaitad due to reduced
ranqa , reduced toraqe diqestibility, and reduced a.aount ot
toraqe available.
K00sa Poraqe Intake K9del
A ruainant aodel, ~evelopad by swift (1983) provided
the concept11al framework tor the davalopaent of a moose
carryinq capacity model. swift's (1983) aodel is basad on
6
daily diq .. tibility and nitrogen concentration and predict.a
vol~~ntary toraqe intaU, rate ot paae&9e, and c:hancJ•• in
lean body .... and body tat. ~ volu.e and rate ot
~P 1e a ay el~t ot thb .oclel, since the anaal ia
aeeu.ect to alway. .. t to ~ till.
~ (1917) and SCbVarta .oditiecl the SVitt (19U)
.odel to pr.dic:t vol~~ntary torap intaU baeecl on body
condition and .-.onal ane~ d_.""•· Studies ot toraqe
intaU by -(Schvart~ at al . 1914) inc11catecl tbet
additional tac:tore other than.~ volu.e and rate ot
~P at teet vol~~ntary toraqe intake in 1100ae . Schwarta
at al. (1914) -.urec~ pby.ioloqical appet.ite chanqee in
.co.. toraqe intake and found ca.plete taeti"9 ot bull aooae
durin9 the rut, and tor .co .. in ~eral, toraqe intaU
r .. checl a peak durin9 the -r aontbe and a low point in
late winter. JteneJter and BwSaon (1915) observed the •-•
qaneral pattern with re.;ard to .. aaonal chanqea in toraqe
intake tor 2 tree ranqiJ\9 -·
7
HUbbert (1917) and Scbvarta .edified swift'• (1913)
.odel by .. tuli8hin9 a aax~ ruaan capacity, which
allow.d ~ till to chanqe ... eonally in r .. ponae to
torap availability, toraqe quality, and an•~ deaanda.
Tbie aodelinq approach allows daily toraqe intake to be
controlled by pbydcal -(ru.en volu.e and rate ot
pae .. qe, •• altered by toraqe quality) and phyeioloqical
neecla (enerqy requir~ta and body condition). Other
aoditicationa included ch&ft9inq how tat and protein etor••
vera anabolized and cataboliaed, and chanc;iliCJ par ... ter
value. to include recent .co•• data on rat.. ot paaeac;• and
~turnover tiae (Rjeljord at al. 1912), aeaeonal
aet&bolic rat .. (Reqelin at al. 1915), protein requir .. enta
(Schvarta at al. 1917), ... eonal dyn .. ica ot tood intake
(Schvarta at al. 1984), body vaic;ht (Schwartz at al. 1986),
and ru.en volu.e (G& .. _y and Coady 1974). Readers d .. irinq
aore intoraation about this aodel should consult HUbbert
(1917).
ovuvin of llocSal Q11qa
Tbe .ooee carryinc; capacity aodel baa a hierarchical
structure, with a aooae population aubaodel and an
individual aoo .. eubaodal. The aooae population aubaodel is
the proca .. tbrouc;h vh.ich the tiae period and area ot
intereet ia specified, and an eatiaate of the .. ount ot
torac;e available to aooae, durinq the apacified tiae period ,
ia obtained. The aain purpose ot the individual aooae
aubaodel ia to aataate the .. ount ot toraqe intake needed
by a .co .. to be aaintained in a healthy condition tor a
specified peri od ot tiae. The Hubbert-Schwarta intake aodel
is used tor t:l\ia purpose, and calculates the aaount ot
toraqe intake required by adult r ... l• aooae. These 2
aub.odela are then joined toqethar to obtain a carryinq
capacity .. tiaate.
ftod•l xnpyt conaid•ratioft.
To uat th1 -• population .W.OCStl, it ia ntetaaary
to ut.anille t!w aru of intenat, the a.ount of foraqe
availablt to _,, the tial period of lnt1H1t, tht
4\lration and typea of habitat lou, and population cUtt
panm~ttra . 'l'b1 am of int~Htt •hould includt all tht
area• vllich will be illpactld by th1 projtct. Chanqinq
projtct dlliqna ofttn chanqt tlle txact boundariu of tll.t
area to be i.Jipacted and it il quution~ll -to whttlltr or
not habitata adjacant to dilt~ am• will be ~ftct.ed ,
thtrafort , tht 1tudy arta lhoul.d be lazv• tnouqh to tnturt
that ~ ar.aa art included.
'1'bl ptriod of tl11 y-.r vllich tlle projtct will afftct
--1houl.d be dlttrained froa •-•onal aoos• cU•tribution
and habitat u&aCJI pettern~. For inatanct, it tlle area beinq
illpac:tld by tha projtct ia aoo•• winter ranq•, tlltn tht tat
period 1D queetion vou.lcS be the date• that aoo•• would
noraally uat their winttr ranq1, provided that lack of
~ ~ il not a laitlnq factor.
one. tha tial ptriod of inttrut hal bltn utal:lliahed,
tht .-nt of and type of IIOOM foraqt in tl11 atudy aru
-t be dltlrained . 'l'b1 1111pl1 cSuiqn ahould allow
inftrtneet to naily be -d• to diffartnt aubatta of tht
1tudy am, ~ ~111 would includt a ay•t.-tic aa.ple
duiqn or a atratified, bued on a VecJitation -p, 1-.ple
cStaiqn . Xf tha area in qu11tion il winttr ranqt, thtn leafy
-ttrial ahoulcS be txcluded troa the toraqe eatiaat11, and
included it the area i• au.aer ranq1. The 1111ount of
avappinq that could tbeorttically occur between it .. s in the
diet nteda to bl dettrained in order to aaaeaa which iteaa
could pottntially be limitinq. Only diet it'ams which have
tht pottntial to be laitinq need be 1111aaur1d . For
inatance, it 111ountain cranberry waa ubiquitoua, but due to
anov cover the 80011 ditt could conai1t of no more than 15t
aountain cranberry, thia apeciea could b1 conaidtred non-
laitinq and at.ply not aaaaured. .OU• to ita hiqh
palatability, the ..aunt of willow forage pr111nt ahould
al-t alway• bl -aaured. Given an eataate of the a111ount
of brovee that i e preaent in the atudy area, the 1111ount ot
brovee available to .0011 auat be deterai.ned i.t tbe area i s
wi.nter ranqe and anov deptha a ake tbe forage cloae to the
qround unavailable . Once the 1111ount ot brow•• avai.lable to
80011 hae been deterai.ned, the aaxi.aua auatai.nable browainq
rate needa to be deterainld tor each apeciea. Tbia' rate
will be uald to deteraine what proportion ot the avai.lable
brovae i a actual ly conauaed by tlle 1110011 .
To uae tlle individual a ooae aublllodel , one siaply rune
tlle llubbert-Schwartz f orage i .ntake 111od1l wi th the par1111ete.rs
s pecified by tlle application. Tb111 par11111ters include the
dem i red co.ndi tion of the IIIOOSI wh i ch we want to 1 support 1 •
At the currtnt tile tlll aodel i a setup to produce h.eal tlly
1110011, obvioualy a piece of habitat could support a ore moose
i t the condition requi r .. ents were lowared. Aniaal
conditi on can bl altered by changing the desired parc.entaga
8
ot body tat body (IIUl:lbert 1917). Aniaal aqe an4 weiqht will
attect the a.ount. ot intake required tor a qiven tiae
period, in qeneral, toraqe int&U incr-••• with increasing
ani.al -iqbt, while incr .. ainq ani.al aqe incr-••s the
• t&rcJeted. • ani.al aile an4 will cause the aniaei to adjust
intake conau.ption to try and. -t this tarqeted. size .
otber pa~tera include diet diq .. tibility and nit.roqen
content. In qeneral, int.au incr .... a with dec~ainq
diq .. tibility until ru.en till ia r .. cbed., attar which
intau 1a pbyaically li.aited.. Ine r .. sinq protein levels · do
not cause tor&9& intalte to vary. lfitroqen and diq .. tibility
valu .. abould retlect diet c011p0aition at carryinq capacity ,
ie) qenerally both diq .. tibility and nitroqen content will
decreaH u leas preterred. it ... are aubatituted tor the
biqhly palatable diet it ....
Applicttign gt th• lpdal tg t he Suaitna Hydroelectric
2ro1tct
Tbe oriqinal plan was to use the •ocS•l aa a tool tor
evaluatinq the ettects ot the Suaitna Hyd r oelectric Project
on ~•• carryinq capacity under a variety ot acanarioa.
This would bava required nuaeroua runs ot the •ocSel uainq
different input& accordinq to the aasu.ptiona ot the
scenarioa. However, the project was auapanded just aa the
intor.ation required tor adaptinq the ~•1 to the project
bee;.-available. The scenarios presented bare are intended
only to illustrate the application ot the •ocSal and to
provide one eat ot aatiaetaa ot the decrease in carryinq
capacity due to apoun~enta, cups, ace••• roads, and other
facilities wbicb will not be rehabilitated. The estimates
presented should not be construed as an aaaasa•ent ot the
iapacta ot the project as a wbola . Different sets ot
aasu.ptiona Wduld provide so•awhat different asti•ates.
Also, not all !.pacts are enco~aaed by the scenarios. Not
included are i•pacts •achani ... which •iqbt alter carryinq
capacity in an areas adjacent to the i•poundmants (Ballard
et al. 1987) or downatra .. (Modattarri 1987). The •ocS•l
could be used to evaluate these ••chaniaaa with appropriate
inputs.
METHODS
Inputs tor tba •ocS•l ware derived in the tollowinq
.. nnar.
1 . Area ot Interest
For the purposes ot this report, the area ot interest
is datined to be the area lost to the i•poundmanta, camps ,
access roads , and other tacilitias which will not be
rababilitated in the 3 staqa Susitna Hydroelectric Project.
The exact areas used i n these desiqn, broken down by the
9
r .. turu luted above, u luted in t&b.lee ll-15 of "llooee
Forqe li-In the Kicldle Suaitna Jtiver leein, Alaau•
(llecltar and lteiqere, 1.917). Areaa adjacent to the
illpo'llwteenta are not included in thie carryi.DI) capacity
eett.ate, h_,er, qiven a hypoth .. ie aa to hov thue areaa
vouM be affected by the project, tha IIOde.l could be uaed to
aitiqate tor 1~• of -earryinl) capacity 1n thue areas .
2 . QuratiQD of QH
lallarcl et. e.l (1917) reported that 1100•• nor.ally
aiqrate into the ~t arua aroun:S the end of January
and tor the purpoeu of thia report February l wae ueed ••
the atartinl) date in the IIUbbert-Schvarta intake IIOdel .
Steiqen at al. (1912) reported that qreen-up in the aiddla
Suaitna ... in uaually oec:ura around the end of April. April
JO th _. uaed •• the andi"9 date in the IIOdel run ainca
d.,.lopinl) -wU.lov and paper birch qrovth , •• well ••
reduced enow level• aaJtinq .ountein cranberry aore readily
avail~la, will eauae foraqe to no lonqer be liaitinq on the
winter rante. Dllrint thU period of tille, daily intake of CAG, by
aooee, tluctuatu qrutly (IIUbbert 1917). The aooee foraqe
intake IIOdal predicted that daily intake would inc~•••
traa &.tlruary t.bzou9b eerly ll&reh, and deer•••• rapidly in
early April (Fiqure l) for aooee inhebitinq the aiddle
Suaitna laein.
3. lU.G
Steiqare and Backer (1986) reported that the
coapoaition of the diet of •oo•• in the aiddla Sueitna
laein, by aonth. Their atudy aleo reported the crude
protein and ni troqen content of the diet by aonth and
dietary it... Tbeee tiqurea vera uaed aa inputa into the
RUbbert-Schwarta intake aodal.
la.ad on data collected by Staiqera and Hal• (1984 ), it
vae decided that reein birch (~ qlanduloaa) waa not a
liaitinq food it-to aooee in the aiddle Suaitna Baain but
that willow Cbl.ixl, papar birch (~ papyritar...) and
aountain cranberry cvacciniua yitia-idata) had the potential
to be lillitinq. Uainq thia intor.ation, Beckar and Staiqars
(1987) eeaaured the aaount of non-leafy, current annual
qrovth, (CAG), for willowa, paper birch and aountain
cranberry 1n the Middle suaitna leain . ...ad on their
eett.atee of the aaount of aountain cranberry CAG, and snow
depthe in the Suaitna baein (Staiqera at. al 1986) it waa
datarained that utilization of aountain cranberry by aooaa,
durinq the winter, wae probably liaited by the abllity of
1100ee to paw tbrouqh the anow. The .. ount of willow and
paper blrch CAG that ia available to aooaa durinq the winter
ia unknown, however, th.ara ia atronq evidence that thla
foraqe la leaa available outaida of the lapoundaenta and
that thaae it ... becoae 1aaa available aa elevation
incraaeee in thee• artae. A two year aooea toraqa bioaass
10
et\ldy (lecbr and Steiqera 1917), -• conducted in the
aiddle Suit.na River ... in in order to eatt.ate the uount
of willow and paper birch CAG that 1a available (above 50 CJI
in beitllt) to-clurinq the winter. Ttl-11tiutaa vera
then U..S aa inputa into the carryinq capacity IIOClel to
qenenta tha carryinCJ capacity aatiaataa.
A NYi .. of diet IIUbtttitution between aountain
~, willow, and paper birch can be found in a.c:Jtar
and Steiqen (1917), tor ~ of thia report, ~untaln
c~ availability will be conaiderecl liaited due to
•nov depth and thu the diet c011p0eition tor thia ccmponant
will not be allowed to cb&nqa. Willow and papar birch will
be allowed to be IIUbtttituted tor one another up to a diet
conaiatinq of 75t paper birch (Becker and Staiqara 1917).
Initial rune ot the -carryinCJ capacity IIOClal incticated
that willow vaa the liaitinq diet it-and that a aurplu of
paper birch axiated. 'l'tla aJIOUnt ot aurplu papar birch w ..
different tor 11ch or the t.pounclaant ataqea and depended
upon vbathar the point 11tt.&te or upper 80t contidance
liait vaa uecl in deteraininq the utilization rata. A
revi .. of auatainable, .oo81 toraqa utilization rat•• can bl
found in leckar and Staiqen (1987), tor tl purpoa11 ot
thia report, .ooae utili~ation rataa ot 60t vera conaidered
autainabl• clurinq IIOClerata wintara with occ .. ional lOOt
Utilization r&tll during I IIVIrl winter.
RESULTS
carrvipq c.aacity latiMtll
1 . "cd·re~• linter -pgint Eatiaat•
In order to produce a aoo11 carryinCJ capacity 11tt.&te ,
during a IIOCltrate winter, baaed on point eatiaataa ot the
a.ount ot brovae available in the aiddle Suaitna Baain
(llcklr and Steiqera 1~87) the aonthly aooaa dieta given in
Steiqera and Becker (1986), (Table 1), vera aoditied. The
IIOCliticationa reflected ditterent degr••• ot avapping ot
papar birch tor willow in each ot tht 3 stag•• ot tht
hydroelectric project (Table 2), and vaa baaed on point
aatiaat11 ot available CAG tor the aontha ot February,
April, and March. Oaing the aaauption that the aaxiau
auatainable CAG utilization rate ia 60\, peraanent habitat
loll troa the Suaitna Hydroelectric Project would cauae a
reduction ot •os aooae i.n tht carrying capacity ot ·~·· in
the ai44le suaitna Blain (Tabla 3).
2. MQderet• Winter -Upptr sot Cgntidance Liait
To create a aooae carrying capacity eati.aate, during a
aoderata wint er, baaed on tht upper 80\ confidence liait of
the aaount ot brow•• available (willow and paper birch CAG
above 50 ca) in the aiddle Suaitna Blain (Bicker and
Steiger• 1987), the aonthly aooae dieta ~ivan in Sttigera
and Becker (1986), (Table 1), wert aoditild. The
11
80Clificationa reflected cUtterwst deqr-ot -•ppinq ot
paper bircll tor will-in .. cb ot the l Staqea ot the
bfdroelectdc project (Table 4), tor the .onth8 ot February,
April, and .. reb. laeed on upper aot confidence eatiaataa
ot a.ailabla CAG and the aaau.ption that the ... tau.
auatainabla utiliaation rata ot CAG ia 60t, peraanant
habitat loaa fro. the Suaitna Hydroelectric Project would
cauae a ·reduction ot 603 .co .. in the carryinq capacity ot
~ in the aiddl• Suaitna Baain (Tabla 5).
l2
Table 1. current -diet CQIII)Oeition durin9 the .Ol'lt.ha
of hlbrwlry, llarch, and April.
February iU'Ch Aprll
Speci .. • Diet • Diet • Diet
Willow 71 71 67
P. Birch 4 4 3
a. Birch 15 15 15 •• Cranberry 10 10 15
Table 2. ~e diet ca.poeition durinq the aont.ha of
February, llarch, and April, vith
birch for willow . The a.oUl'lt of
-appift9 of exc-• paper
excess birch vas based on
poil'lt .. tt.atea of the a.oUJ'It of .oose foraqe available.
fiiPOUiid. February Mardi April
Staqe Spec:i-• Diet • Diet • Diet
Willow 65 65 61
I •• Birch 10 10 9
a. Birch 15 15 15
•• Cranberry 10· 10 15
Willow 65 65 61
II P. Birch 10 10 9
R. Birch 15 15 15 •• Cranbe.rry 10 10 15
Willow 53 53 50
III P . Birch 22 22 20
R . Birch 15 15 15
M. Cranberry 10 10 15
'
l3
Table 3. Point uti.aate ot aooae carryinq capacity in a
IIOClerate year, by Iapoundaent Staqe, tor the Susitna
Hydroelectric Project. Theu calculations are baaed on the
uti.aated a.ount ot current annusl growth above 50 c=-in
heiqht in each Staqe and exc lude the borrow pita which will
ba available as aooae habitat attar aite rehabilitation.
Iapound. Willow b Papar Birch b Moo•• c
Staqa • Mi~ Bioaaaa (Itq) Bioaa .. (ltq) c.c .
I 10.09 31,313 4,694 190.5
III 10.15 26,464 4,327 162.9
I ' III 20.24 353.4
II 4 .00 7,056 2,932 50 .9
I,II,III 24.24 404.3
a -When tiniabed the Watana daa will conaiat ot ataqaa I
and III; the Davila Canyon daa will consist ot Staqa II .
b-Bioaaaa aatimataa are troa Backer and Staiqara (1987).
c -Th••• carryinq capacity aatiaataa are baaed on a 60t
utilization rata ot brow•• currant annual qrowth by
aooaa (Backer and Staiqa.ra 1987) .
14
Tele 4. Moo•• diet coapo•ition durinq the •onth• or
February, March, and April, with -appinq or exc••• paper
birch tor willow. Tbe -ount or axe••• birch wa• ba•ed on
upper lOt contidence li~t• or the a.ount or •oo•• toraqe
availele.
I~una.
Staqe Specie•
Willow
I P. Birch
R. Birch
M. Cranberry
Willow
II P. Birch
R. Birch
"· Cranberry
Willow
· III P. Birch
R. Birch
M. cranberry
ribruary
t Diet
64
11
15
10
63
12
15
10
49
26
15
10
MarCh April
t Diet t Diet
64 59
11 11
15 15
10 15
63 59
12 11
15 15
10 15
49 46
26 24
15 15
10 15
15
TUlle 5. upper confidence .. tiaat.. of 1100ae earryinq
ca.-city in a IIOCierate year, by t.poundaent sta9a , f or tha
SU.itaa llfUoelectrie Project . 'l'b ... ealeulationa an ba.ad
on tile liPPU' lOt conticleDee U.ait on the eJIOUDt of current
annual 9Z'GWtJl above 50 ea in bei(Jtlt in each Stefie and
exclude the borrow pite vbic:h will be availa!lla •• aooee
ba!litat attar alta reba!IUitat ion_.
~· 1112
WUlov b Paper Birch b 1looee e
ai-.a (Jttl) 81011&•• (Jttl) c.c.
I 10.09 43,921 7,115 272.7
III 10.15 39 ,327 7 ,229 24 5.0
! • III 20.24 517 .7
II 4.00 11,04 1 5 ,115 U.l
I,II,III 24.24 602.5
a -Wben finiabed the Watana claa will eonalat of ataqaa I
and III ; the Davila canyon claa will eonabt of ataqa II.
b -Bioaaae .. t~t .. ara froa Becker and Staiqare (1917).
e -'l'beu earryinq capacity aatiaat .. are baaed on a 60t
utilization rata of b r ovae currant annual qrovth by
~• (Backer and Staiqara 191?).
16
17
3 . Styl£9 Wint•r-pgint latiaat•
To qiDirat• a .0011 carryinq capacity e1tiaate, during
a aevere winttr, ba1td on the point 11ti.aate ot tht .. ount
ot brovM available (willow and paper CAG above 50 c::a ) to
.oote in the aiddlt Suaitna latin (l&clttr and Sttigtrl
1917), the .ontbly .0011 dittl given in Steigtrl and Blclttr
(1986), (Table 1), -rt 80dititd. Tht 80diticationa
r•tltcttd dittuent dtqrlll ot avapping ot paper birch tor
willow in each ot the 3 Staqea ot tht hydroeltctric projtct
(Table ~), tor tht :aonthl ot Pabruary, April, and Karch.
l<d on point 11tlaat11 ot availablt CAG and tht a11u.ption
that lOOt ot tht CAG ia utiliztd, peraanent habitat 1011
troa tht Su1itna Bydrotllctric Projtct vould cauae a
reduction ot 674 aooat in tht carryinq capacity ot aoo11 in
tht aiddle suaitna Blain (Table 6). The lOOt utilization
rate could bl auataintd in ltvtrt winttra aa long aa no more
than 4 11vtr1 wintera oc:currld within any 10 ytar period
(Btcklr and Sttigtra 1917).
4) 3•v•r• Winttr -Upptr aot contidtnct Inttryal
Tht aonthly aoo11 ditta qivtn in Sttig1r1 and Blcktr
(1986), (Tablt 1), Vtrl 80ditild to product a ••v•r• winttr
aoo11 carryinq capacity 11tiaat• uainq tht upper sot
contidlftCI liait ot tht aaount ot brov11 availible, (willow
and paper birch CAG a.bovt 50 c::a) to aoo11 in tht aiddlt
Suaitna Balin (Bicker and Sttiqtra 1987). Tht
aoditicati~na retltc~ld ditterent ~eqre11 ot 1wapping ot
paper birch tor willow in each ot the 3 Stage1 ot the
hydrOiltctric Project (Table 4) , tor the aonth1 ot February ,
April, and Karch. Ba11d on the a11uaption that lOOt ot the
available CAG would bl utilizld, peraanent habitat 1011 troa
tht Su1itna Hydroellctric Project would cau1e a reduction ot
1,005 aoo1e in tht carrying capacity ot aoo11 in the aiddlt
Su1itna Blain (Tablt 7).
Moo11 carrying capacity e1tiaate1, during a aodtrate
winter, uaing both point e1tiaate1 and upper sot conti dence
liaita ot the .. ount ot available CAG are expre11ed in teras
ot aoo1e denaity in Table 8. Moose carrying capacity
11tiaate1, during a 1evere winter, u1ing both point
e1tiaate1 and upper sot contidence limits ot the amount ot
available CAG are expre1aed in teraa ot aoo1e density in
Table 9.
Table 6. Point .. tillate oC 800 .. c:arryinq capacity in an
.-re winter year, by ~t Stage, tor the Suaitna
Hydroelectric Project. Tb ... calculationa are ba•ed on the
eet~ted -t ot current annu.al growth above 50 ca in
hei¢t in .. c:h Stage and exclude the borrow pita which will
be available a• 800•e habitat attar •it• rehabilitation.
~· Willow b Paper Birch b Koo•• c
Staqe a lliz Bioaa•• (~) Bioaa•• (Jtq) c.c.
I 10.0t 31,313 4,694 317.5
III 10.15 26,4U 4 ,327 27l.5
I ' III ZO.H 589 .0
II 4.00 7,056 2,932 84.9
I,II ,III H.24 673.9
a -When tini•hed the Watana daa vill conei•t ot •tag.. I
and III: the Devil• Canyon daa vill conei•t ot •taqe II.
b-Bioaa•• .. tiaat•• are troa Becker and Steiqera (1987 ).
c -Tbe .. c:arryinq capacity .. tiaate• are ba•ed on a 100'
utilization rate ot brovae current annual .qrovth by
.aoae (Becker and Steiqera 1987).
1 8
Table 7. Upper confidence .. ti.aate ot 1100•• carryinq
capac~ity in a HVere winter, by I~t Staqe, tor the
suait:Da llydroel6Ctric Project. Th••• calculation• are baaed
on the upper lOt confidence eatiaate ot the a.ount of
cun•t annual qrovth above 50 ca in height in .. ch Stage
and exclude the borrow pita vtlich will be available .. 1100••
habitat atte: •it• rehabilitation.
x.pouncS.
lli2
Willow b Paper Birch b Moo•• c
Staqe a Bicmaaa ()(g) liOIIa•• (Jtg) c .c.
I 10.09 43,921 7 ,115 454.5
III .1.0.15 39,327 7,229 408 .4
I ' III 20.24 162.9
II 4.00 11,041 5,815 141.3
I, II, III 24.24 1,004.2
a -When tiniahed the Watana daa will conai•t of •tag•• I
and III ; the Devil• Canyon daa will conai•t of •tage II .
b-Bioaaaa ••ti.aate• are !rom (Becker and Staiger•, 1987).
c -ThUe carrying capacity e sti-tu are ba•ed on a lOOt
utilizat~on rate of browse current annual qrovth by
aooae (Becker and Stei qar•, 1987).
19
Table 1. C&rryinCJ capacity utaatea •• expruaed in 8008e
anaity, by ~t suqe , cSurinCJ an IIOderate winter .
~ uti.Mtu exclude abort tera loe ... ot 1100ae habitat
clue to borrow pita.
fiPOiiiia. Point EatlUte Upper Contldance Eatiaate
Staqe • carryinCJ ca~citY Carryin9 capa~itY
(IIOOH/ai ) (Kooae/ai )
I 19 .3 27.1
III 16 .4 24.8
I ' IIJ 17 .1 26.3
II 13 .5 22 .8
I ,II ,III 17.1 25.7
a -Wban tiniahecl th.e Watana daa will conaiat ot ataqea I
and III; the Oevila canyon daa will conaiat ot ataqe II .
b -'l'b ... carryinCJ capacity eatiaat .. are baaed on a 60 \
utilization rate ot brovae current annual qrovth by
.ooae (Becker and Steiqera 1987).
2 0
Table 9. c:&rryinq capacity eetaatu aa expreaaed in 1100ae
clenaity, by ~t Sta9e, durinq a aevere winter year. n-eetaatee exclude loe-• of 1100ae habitat due to
borrow pita vllich will have been rehabilitated.
!:;':1· POlJit iitliite b Opper Confidence Eat~te
carryinq ca~city Carryinq Cap!city
(llooae/ai ) (Moo••l•i )
I JZ.l ... 3
III 27.3 41.3
I ' III 29.7 43 .8
II 22.5 38.0
I, II, III 21.5 42.8
a -Wben tiniahed the watana daa will conaiat or ataq•• I
and III ; the Devil• canyon daa will conaiat or ataqe II.
b -~ c:arryinq c .apecity utaatu are baaed on a lOOt
utilization rate or brovae current annual qrovth by
aoo .. (Becker and steiqera 1987).
COJfCLIJSIOJIS
OMI of the pu.rpoeea of this report va. to qive an
overview of the WIOO .. carryinq capacity IIOdel. This IIOde l
b hierarchical in structure and conabta of tvo aubllodela,
a -population .W.OCS.l and an individual -•
r•b-o«'el. The -t aenaitive par-ter in the WIOOse
popllation aw.odel ia detu.ininq the UIOimt of browse
which ia available to WIOO-aa foraqe, vtlile in the
individual WIOO-.W:.OCSel, aniaal condltion and diet
diqe8tibility are the -t aenaitive par ... tere . OVerall ,
deteraininq the ..aunt of available WIOOse forage ia the aoat
aenaitive par ... ter in the generation of a aooae carryinq
capacity .. tiaate.
Another purpose of this report vas to biqbligbt bow tbe
carryinq capacity liOdelinq approach could be uaed to
aitigate for habitat loaa. This process ia very flexible
and allows one to generate WIOOae carryinq capacity eatiaates
under different biological aaauaptiona about aoo... In
addition it ia very ... y to develop new carryinq capacity
.. tiaat .. vtten the p~jact d .. iqn ia chanqed.
Por aitigation of loaa of aooae carryinq capacity
durinq both a IIOderata and severe winter, the r .. ulta baaed
on the upper lOt confidence liaita should be uaed. The
point eatillata on the ..aunt of CAG in the aiddle suaitna
Basin will be off froa the true value by aa.e unlalown
..aunt, and the qruter the d..and to be close to the true
value ·the leas certain we are of beinq that close (Stuart
1976). In teraa of affectinq the acoae population, an
under .. tiaate of the aaount ot CAG available to aooae in the
aiddle Suaitna Basin will produce an undereatiaate of the
nuaber ot .oou tor which to aitigate (baaed on carrying
capacity eatiaatea), and aa a result, not enouqb
co.penaation would be done to offaet the potential loaa of
acoae due to thia hydroelectric project. To ainiaize the
probabi l ity of failing to fully coapenaate tor loaa, an
upper confidence liait should be used in the carryinq
capacity eatiaate. P'or this report, the upper Silt
confidence liait on CAG of acoae brovae waa used, since it
balanced the deaire to be fairly certain that loaa of aoose
habitat waa fully co~aated for and liaited the
probability of aajor overcoapenaation. Given the
conaequenc .. of the•• 2 typaa of errors it aay appear that a
90 or 95t upper confidence liait should have been uaed,
however, if the distribution of CAG esti aatea b
approxiaatel y noraally distributed than there ia only a lOt
chance that •co•• would be under-coapensated for. In
addition, the level of precision that aoat gaae aanaq .. ant
project• can aver hope to achieve is the sot confidence
level, due to the inherent noise in biological ayat ....
The uae of the upper sot confidence liait , in
detaraininq available CAG, results in a trade ott between
apendinq aoney on iapact assas .. ent to qat aore precise
aatiaataa of the aaount of CAG available to aooae, or
22
2 3
~"'UJ!J9 .on wmey on aitiqation vorlt u a result of l arcJer
confidence liaiu. tJail'9 utiaataa of .-pl11'9 and
aitiption c:oRa and the torwula (a/n ) one can det.raine
tM optt.al allocation be~ the coat of C)ett11'9 pr.ciae
..tt.atee of the a.ount of CAG available to .oo-and the
coat of ait1qatil'9 tor additional -·
'l'be -carry11'9 capacity IIOdal ia an .nr-ly
valuaJ:Il a and~ tool to a.-a the Uipact of a project
on aooea . B~, tha i.Dtarancaa obtai.Dad troa tha IIOdal
ara aceDario ..,.c:itic, ancS aa a result, i t ia very illportant
to ..,.city tha .odel input. correctly. on the .ooae
population laval thaaa i.Dpuu includa apec:ityinq tha area of
intaraat , tha typaa and a.ount of tora9e ayail&bl• to .ooae,
the tt.a period of intaraat, tha duration and typaa of
habitat loaa, the population diat par ... ten . on tha level
ot the individual .oou it ia illportant to apec:ity the
daairad condition of tha .ooaa, tha ant.ala a9a and vei9ht,
and tha nitro9an contant and di9aatibil ity of tha d i at.
.. ...
Pl&un 1. DAILY I NTAI-\E OF CA G B Y M OOSE
Bosed on T oble 1 diet composi t i on
JJ
28 j 2 .6
2 .4
...... 2 .2 Gl
.>1. ...... 2
i 1.11 e
0 1.6
0
:J 1.4 c
~ 1.2 .. c ~
:J u 0 .11
0 .6
0 .4
0.2
0 J JO 50 70 90 110
Julion Doy
0 Doily lntoke
Ballard, w.B. and J .s. Whiaan. 1917. suaitna
Hyclroel•'"t.ric Project, Biq G-• Studies, Pinal Report,
Vol. II -Moose -O'patreaa. Alaska Dept. ot Piah and c:....
Becker, J.P. and w. D.Steiqera, Jr. 1987. Suaitna
Hydroelectric Project, Biq c:-e Studi .. , Pinal Report,
Vol. III -Moose toraqe bioaaaa in the aiddle Suaitna
River baain, Alaska. Alaska Dept. ot Piah and Gaae.
ll3 pp.
Gasaway, w.A. and J.W. Coady. 1975. Review ot energy
requi~ta and ruaen teraentation in aooae and other
ruainanta. Paq .. 227-262 in J. Bedard ed. .Uces Moose
lcoloqy. Lea Preas .. De I.'Oniveraite Laval, Quebec
74lpp.
Hjeljord, o., P. Sundatol, and H. Haaqenrud. 1982 . Tho
nutritional quality ot browse ·to aooae. J. Wildl.
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Hobba,.·M.T., D. I.. Bakar, J.l. Ellis, O.K. Switt and R.A.
s;reen. 1982. Energy and nutrition baaed .. tiJuatea ot
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46:12-21.
Hobbs, M.T. and D.M. Svitt. 1985. EatiJuatea ot habitat
carryinq capacity incorporatinq explicit nutritional
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Hubbart, M. 1987 . The ettecta ot dietary quality and
quantity on energy partitioninq in aooae. Ph.D. Thesis.
Oniv. ot Alaska, Fairbanks. 158 pp .
Mautz , w.w. 1978. Nutrition and carryinq capacity. Paqes
321-348 in J.I.. Schaidt and D.I.. Gilbert, ada. Biq Game
ot North Aaerica. Stockpola, Harrisburq, Pa. 494 pp.
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Gaae Studies, Pinal Report, Vol. I -Kooae -
Downatre-. Alaaka Dept . ot Fish and Game.
Moen, A.M. 1973 . Wildlite Ecoloqy: An Analytical Approach.
Pre~, San Franciaco, CA. 458 pp .
Reqelin, W.I.., c. c. Schwartz a.nd A.W. Franzmann. 1985.
Seaaonal enarqy aetaboliaa ot adult aooae. J. Wildl.
Kanaqe . 49:388-393 .
25
Ranaker, L.A. and R.J. Hudson. 1986. Seasonal foraging
rates ot tree-ranging aoose. J . Wildl. Manage.
50:143-147.
Ranaker, L.A. and R.J . Hudson. 1985 . Eatiaation ot dry
aatter intake ot tree-ranging aoose. J. Wildl. MAnage .
49:785-792.
Robbins, C.T. 1973. The bioloqical basis tor the
deteraination ot carrying capacity . Ph.D. Thesis .
Cornell University, Ithaca, N.Y. 123 pp.
Schwartz, c.c., W.L. Raqelin and A.W . Pranzaann. 1 984.
Seasonal dynaaics ot food intake in moose. Alces
20:223-242.
Schwartz, c. c., W.L. Raqelin, and A.W. Franzaann. 1986.
Annual weight cycles of aoose. swedish Wildl. Res .
Viltrevy. (In press).
Schwartz, c.c., W.L. Regelin, and A.W. Pranraann. 1987.
Protein digestion in aoose . J . Wildl. Manage. 51:
352-357.
Steiger• w.o., Jr., W.B. Ballard, E.P. Becker. 1986. Karch
1985 snow depth _survey in the aiddle susitna River
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