This file was created by scanning the printed publication.
Errors identified by the software have been corrected;
however, some errors may remain.
Studies on the Restillg Site Ecology of
Marten in the Central Rocky Mountains
Steven W. Buskirk, Henry J. tiarlow, and Steven C. Forrest 1
Abstract--Studies on the resting site ecology of marten (Martes americana) In the central Rocky Mountains are described. Body temperature dynamics, ambient temperature-specific metabolic rates, ecological characteristics of resting sites and the relationship between resting site use and
environmental factors are being studied. These studies will provide insight
into t~e basis for the old-growth association of marten.
The marten (Mortes americana) has been se.le.c.te.d as a
manageme.nt indicator species by several national fore.sts of
the intermountain \-Vest. One ecological trait makes this
designation particularly appropriate; marten are among the
most habitat -specialized of N orthAmerican mammals (fig. 1),
being largely restricted to conifer-dominated forests and
attaining their highest densities in late successional stands
(Allen 1984). Harris (1984) considered marten to be among
the most clima'"{-dependent of North American forest mammals.
What are the bases of the. old-growth de.pendency of
marte.n? Do marten require old-growth because of the types
of prey that are found there, because of favorable access to
prey, because of the availability of predator-avoidance habitats to marten themselves, or because of the availability of
features that are important as thermal cover? Our studies are
directed at understanding how marten may use specific forest
habitat features to thermoregulate in winter.
A number of resting sites used by free-ranging marten have
been described (table 1). These sites range from the forest
canopy to beneath the soil surface. Particularly in winter,
resting sites are often associated with coarse woody debris,
including logs and stumps, below the snow surface (Spencer
1981, Ste.Yenton and l\fajor 1982, Martin and Barrett 1983). In
summer, marten usually rest in sites above the soil surface,
ofte.n in the canopy layer (Burnett 1981, Martin and Barrett
1983). However, it is not dear whether these sites were
selected on the basis of convenience, or other factors. It is an
objective of our studies to monitor physiological and microen··
vironmental in order to help discern this relationship.
Although several mustelid species have received attention
from physiologists because of their long, thin shapes and
consequently high surface area/mass ratios (e.g. Brown and
Lasiewski 1972, Iverson 1972), few metaboliG or energetic
studies of martenhaye been undertaken. 'Vorthen and Kilgore
(1981) found that the lower critical temperature (.Ik' the
ambient temperature (I.a] below which an animal mustShlver
to maintain its body core temperature lIb]) of marten was 29 0
C, which is higher than the I experienced by free-ranging
marten for most, if not all of t~e year. In an associated study
on metabolic responses by marten to low.Ills, we reinvestigated this relationship and calculated a considerably lower
value of Ik of 160 C. Even with this lower (and more adaptive)
value, the thermal relationship of the marten to its environment is a tenuous one. During winter, when marten must
maintain Ib-I . gradients of up to 80 0 C, andI.as are 11-570
C below our ca1culated.I,k, energetic costs of foraging and of
resting above the snow surface must be very high. These
postulated energy losses caused us to suspect that marten
would be highly selective in their choice of resting sites during
winter, and would exhibit patterns of resting site use that were
keyed to weather variables.
Study Area and Methods
Field studies have been carried out in the Snowy Range
re.gion of the l\fedic.ine Bow National Forest, in southeastern
,\\Tyoming. The approximately 10B-km2 study area ranges from
2,500 m to 3,300 min ele.va.tion and indudes two forest z.ones,
one dominated by Engelmann spruce (Picco engelmannii) and
subalpine fir (Abies iasiocarpa), the other by lodgepole pine
(Pinus contorta). Spruce-fi.r stands conta.in large, old trees,
hold large amounts of large dead woody material, are unevenaged and generally meet criteria (Franklin et a1.1981) for oldgrowth forest. The area is used intensively for recreation, with
1Department of Zoology and Physiology, Box 3166, University of
Wyoming, Laramie, WY 82071.
150
Table 1. Resting sites reported to be used by American marten, by type.
RESTING SITE CATEGORY
Sites> 2m Above Ground
CITATION
AND
SEASON
OF
STUDy1
Canopy Layer
ij
~
.~
c:
·e
~
..c:
()
c:
.2
<i:i
c:
~
g
.D
c:
0
e
.D
~
u
~
Cii
~
'" ~
·s
CD
..c:
~
E
::J
~
cr
en
11
8
1
2
2
.~
::-
~
en
c:
5i
E
.D
.s:
«I
~
.D
>.
en
~
en
1
Other
CD
a
1»
-J
>.
"0
:::>
Burnett (1981)
Spring, Summer, f'a/I
Winter
Buskirk (1984)
Spring, Summer, Fall
Winter
Campbell (1979)
Spring, Summer, ~all
Winter
Hargis and McCu"ough (1984)
Spring, Summer, Fall
Winter
Hauptman (1979)
Spring, Summer, Fall
Winter
Marshall (1942)
Spring, Summer, Fall
Winter
Martin and Barrett (1983)
Spring, Summer, Fall
Winter
Masters (1980)
Spring, Summer, Fall
Winter
Mech and Rogers (1977)
Spring, Summer, Fall
Winter
Newby (1951)
Spring, Summer, Fall
Winter
Simon (1980)
Spring, Summer, Fall
Winter
Spencer (1981)
Spring, Summer, Fall
Winter
Spencer (In press)
Spring, Summer, Fall
Winter
Steventon and Major (1982)
Spring, Summer, Fall
Winter
Wynne and Sherburne (1984)
Spring, Summer, Fall
Winter
Sites < 2m Above Ground
Coarse Woody Debris
c:
~
e
~
en
c:
'" '"
iii
CD
~
~
~
~
~
CD
.D
'0
g.
I-
a.
E
:::>
..c:
lii
c:
:::>
E E
~
CD
c:
~
a
"0
CD
~
-g
~
a
~
.0..
lii
..c:
~
0
·in
~
.5
.5
=>
3
1
a
c:
CD
~ ·e
~
"0
....J
c:
~
c:
:I::
01
~
.0..
0
'"
.N
~
en I -
~
·s
cr
en
~
g
:::>
.D
(;j
Cii
CD
c:
~
'"~
"t
(;j
~
::>
U
.§.
CD
()
~ 5'"
CD
~
'"
E
'"
~
a
lii
(ij
(5
I-
1
1
20
16
6
37
.~
.S;
0«
0«
c:
§
:;:
~
c:
=>
5
MT
1
4
1
AK
3
28
WY
5
14
4
23
CA
2
WY
1
8/7
2
1
22
3
1
16
12
16
2
13
16
46
5
19
41
10
1
CA
16
6
21
36
3
3
1
1
1
2
24
18 124
117
NY
3
5
MN
1
4
2
2
7
5
3
WA
X
CA
5
1
4
8
X
X
12
26
3
36
CA
6
12
3
4
7
5
7
3
13
6
3
2
4
1
52
43
7
WA
2
11
9
ME
2
1
ME
612
2
18
312
2
19
2
4
Spring, Summer, Fall considered snow free.
Daytime temperabJres generally aver O· c.
3
25
8
39
2 Natal (maternal) den.
X Occurs in category.
about 140 summer cabins and a public ski area. More detailed
descriptions of the study area are provided by Oosting and
Reed (1952), Billings (1969), and Fahey (1983).
l\iarten were captured in baited live traps using oil of anise
as a lure. Traps were placed in protected sites and were
provided with floors of closed-cell polyurethane foam. Trap··
ping was conducted for periods of 2-10 nights on an intermittent basis from November 1985 to February 1986 and from
November 1986 to January 1987. The total effort involved 496
trap-nights at an estimated density of 1.8 traps/km snowmobile
trail. No injury or mortality to marten resulted from trapping
operations. Captured animals were transported to the University ofWyorning. Under ketamine hydrochloride anesthesia, a
pre calibrated .Th··sensitive tra.nsmitter (1\1inirnitter Model L)
was surgically inserted into the peritoneal cavity and sutured
to the mi.dventra.l abdominal wall. A radiocollar (AV1\1 Instrume·nt Co.) was affh:ed to eac.h animal. After recovery, eac.h
animal was released at the capture site.
151
Radio tracking has been conducted by snowmachine and
on foot during daylight hours. "'hen marten have been found
resting, the resting site has been marked and a recording
de·vice left within 15 m of the site to sam pIe and record
transmissions from the radio implants. Each recording device
consists of a transistor re.ceiver with crystals matched to the
frequencies of the. temperature implants, a solid state timing
de.vice with controls for setting the duration of the. signals
recorde.d and the. intervals between between readings, and an
inexpensive cassette tape deck, all powered by cold resistant
lithium batteries. Tapes of transmitted dicks have bee.n conve.rted to Ib manually using ca.1ibration curve·s. Standard
weather data was recorded by four climate stations within the
study area. In addition, temperature data were gathere.d for 7
sites above and within the snow layer of an old-growth sprucefir stand.
ffl
40
C
o
III
ii:
w
CI
z
1=
30
ffl
a:
c
z
c(
III
W
....
20
in
CI
z
1=
III
W
a: 10
LL
o
III
a:
W
III
:5
~
O~~A--L~--~~~~L-~~--~~_WLIT~C~H'SL-~UN~D~ERL-~T~R~EEL
BROOM
CABltI
BRANCH
Figure 2.--Numbers of resting sites (solid) and numbers of resting
episodes (shaded) used by marten In the Snowy Range of southeastern Wyoming, winters of 1985-86 and 1986-87, by type.
Results
Body temperature dynamics, patterns of resting site use
and activity patterns of eight marten (six male.s, two females)
were studie.d ove·r two winter fie.1d seasons. No radio collars
and only two temperature implants failed prematurely. Over
1,300 measurements of Ib were made. during 93 re.sting
episodes. These data are stiITbeing analyzed: but it is apparent
that marte·n exhibited considerable daily lability of .Ib' Depression of observed I,bs below active levels did not exceed
5.10 C. Such a hypothermic state would produce a deep sleep,
but not the torporous condition typical of true hibernators
(Swan 1974). "'e are currently looking at the relationships
among weather factors, duration of resting episodes and depth
of Ib depression during rest.
FIfty-seven resting sites used by marten during winter were
c.hara.c.te·rize.d. I\farte.n rested in site.s that were ge.nera.1ly
associated with coarse woody debris or rockfields (fig. 2). The
highest rates of reuse were observed in site.s that were associate.d with logs or stumps or were beneath cabins (fig 2). "'e are
c.urrently looking at the distribution of winter resting sites in
re'!ation to mapped stand types and major topographic features.
Discussion
Canis latrans
C. rufus
C.lupus
Alopex lagopus
Vulpes vulpes
V. macro tis
V. velox
Urocyon cinereoargenteus
Ursus americanus
U. arctos
Bassariscus astutus
Procyon lotor
Martes americana
M. pennanti
Mustela erminea
M. nivalis
M. frenata
M. nigripes
Gulogulo
Taxidea taxus
Spilogale putorius
S. gracilis
Mephitis mephitis
Felis concolor
F.lynx
F. rufus
•·1· •••..
•••••••• .••
•. ·1· •••••••••.•.. •.
•
• •••••
• •
.
.
...........
.
·
.
.
.
..
.
......
.
• • • • • •• •••• •• •
..·.........• .• ...• .• .• .• .• .• .• .• .
··..........
.
.
.
.
.
..
· .......• ..• ..••.• ....•
·.... .
·• .• .• .• .••...• .•••••••
.......
•
·1
•
I
I
••••••••
•
••
•
•
•
••
••
•••••
••
• •• •
•• • ••••••••••••
Figure 1.--Distributlon of NOI·th American Ca.l'nivora with ra.nges
mostly nOl1h of Mexico in major biomes ma.pped by Aldrich
(1963). Bioines in which a species has occurred commonly In
historic times are dotted. Mammal classification follows Jones
et al. (1982).
The close associati.on of marten with old-growth stands,
combined with the high monetary values of these stands and
their long rotation times (Oosting and Reed 1952) c·ause us to
anti.cipate that the marten is likely to be a sensitive species in
management of subalpine forests of the c.entral Rockies
during the next two decades. As fragmentation of old-growth
forests continues, managers will be increasingly presse.d to
document the responses of marten to this habitat alteration.
An understanding of how management practices influence the
habitat mosaic provided to marten, including their use of and
dispersal through various cover types, and use of corridors
between critical habitat components will be necessary. Ultimate.!y, habitat requirements that provide for the genetic and
demographic viability of populations through will have to be
described.
Our research addresses key components of the functional
importance of old-growth features to marten thermore.gulatory behavior. How marten thermo regulate by modulatingTb'
how they use protected microenvironments to minimize heat
loss, and how their use of microhabitats varies with weather
may go far to explain why marten are· so close.Jy associated with
old-growth, during winter. A solid understanding of the criti-
152
cal habitat compone.nts of this species will provide a more
meaningful definition of what marten ecological features
ma.rten may indicate, and how ma.rten may be more effective.!y
managed in forest ecosystems in the. future.
Literature Cited
Aldrich, J. Vl. 1963. Geographical orientation of American
Tetraonidae. J. Wildl. 1\lanage. 27:529-545.
Allen, A. V\'.1984. Habitat suitablility index models: marten.
U.S. Fish and Wildlife Service FWS/OBS - 82/10.11.
Revised.
Billings, W. D. 1969. Vegetational patte.rns near alpine timberline as affected by fire - snowdrift interactions. Vegetatio
Acta Geobotanica. 19:192-207.
Brown, J. H., and R. C. Lasiewski. 1972. Metabolism of
we.asels: the cost of being l~ng and thin. Ec.ology 53:939943.
Burnett, G. W.1981. Move.ments and habitat use of marten in
Glacier National Park, Montana. 1\1.S. Thesis, Univ. of
1\fontana, l\1issoula. 130p.
Buskirk, S. W.1984. Seasonal use· of resting sites by marten in
south-c.entral Alaska. J. Wildl. Manage. 48:950-953.
Campbell, T. M.1979. Short -term effects of timber harvests on
pine marten ecology.1\f.S. Thesis, Colorado State Univ.,
Fort Collins. 71p.
Fahey, T. J.1983. Nutrient dynamics of above-ground detritus
in lodgepole pine (Pinus contorta ssp. latlfolia) ecosystems, southe.astern Wyoming. Eco!. 1\fonogr. 53:51-72.
Hargis, C. D., and D. R. McCullough. 1984. V\'inter diet and
habitat selection of marten in Yosemite National Park. J.
Wildl.1\fanage.48:140-146.
Harris, L. D. 1984. The fragmented forest. Univ. of Chicago
Press. 211p.
Hauptman, T. N.1979. Spatial and temporal distribution and
feeding ecology of the pine marten. 1\1.S. Thesis, Idaho
State Univ., Pocate.llo.
Iverson, J. A.1972. Basal energy metabolism of mustelids. J.
Compo Physiol. 81:341-344.
153
Jones, J. K., Jr., D. C. Carter, H. H. Genoways, R. S. Hoffman,
and D. W. Rice. 1982. Revised checklist of North American mammals north of 1\fexico, 1982. Occ. Pape,rs Museum Texas Tech. Univ. 80:1-22.
Marshall, V\'. H. 1942. The biology and management of the
pine marten in Idaho. Ph.D. Thesis, Univ. of 1\fichigan,
Ann Arbor. 107p.
Martin, S. K., and R. H. Barrett, 1983. The importance of snags
to pine marte·n habitat in the northern Sierra Ne.vada. p.
114-116. In: Snag habitat management: the proceedings of
the symposium. USDA For. Servo Gen. Tech. Rept. Rl\f99.
Masters, R. D. 1980: Daytime resting sites of two Adirondack
pine martens. J.l\fammal. 61:157.
Mech, L. D., and L. L. Rogers. 1977. Status, distribution and
movements of martens in northeaste.rn 1\finnesota.
USDA For. Servo Res. Pap. NC-143.
Newby, F. E. 1951. Ecology of the marten in the Twin Lakes
area, Chelan County, Washington. M. S. Thesis, State
College. of Washington, PUllman.
Oosting, H. J., and J. F. Reed. 1952. Virgin spruce-fir of the
1\fedicine Bow Mountains, Wyoming. Ecol. Monogr.
22:69-91.
Simon, T. L. 1980. An ecological study of the marten in the
Tahoe National Forest, California.1\f. S. Thesis, California State Univ., Sacramento.
Spencer, W. D. 1981. Pine marte·n habitat preferenc.es at
Sagehen Creek, California. M.S. The.sis, Univ. of California, Berkeley. 121 p.
Spe.ncer, V\'. D. (In press.) Seasonal rest site preferences of
martens in the northern Sierra Nevada. J. V\'ildl. Manage.
Steventon, J. D., and J. T. Major. 1982. Marte.n use of habitat
in a commercially clear-cut forest. J. V\'ildl. Manage.
46:175-182.
Swan, H. 1974. Thermoregulation and bioenergetics. American Elsevier, New York. 430p.
V\'orthen, G. L., and D. L. Kilgore. 1981. Metabolic rate of pine
marten in relation to air temperature. J. Manmlal. 62:624628.
V\Tynne, K.1\f., and J. A. Sherburne. 1984. Summer home range
use by adult marten in northwestern Maine. Can J. Zool.
62:941-943.