Index of Species Information
WILDLIFE SPECIES: Lepus americanus
Introductory
WILDLIFE SPECIES: Lepus americanus
AUTHORSHIP AND CITATION :
Sullivan, Janet. 1995. Lepus americanus. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station,
Fire Sciences Laboratory (Producer). Available:
www.fs.usda.gov/database/feis/mammal/leam/all.html [].
Revisions:
18 July 2013: DeGraaf, Richard M.; Rudis, Deborah D. 2001 citation corrected to
DeGraaf, Richard M.; Yamasaki, Mariko. 2001.
ABBREVIATION :
LEAM
COMMON NAMES :
snowshoe hare
varying hare
snowshoe rabbit
TAXONOMY :
The currently accepted scientific name of the snowshoe hare is Lepus
americanus Erxleben [18].
Accepted subspecies include [18,38]:
Lepus americanus americanus Erxleben
L. a. cascadensis Nelson
L. a. columbiensis Rhoads
L. a. dalli Merriam
L. a. klamathensis Merriam
L. a. oregonus Orr
L. a. pallidus Cowan
L. a. phaeonotus J. A. Allen
L. a. pineus Dalquest
L. a. seclusus Baker and Hankins
L. a. struthopus Bangs
L. s. tahoensis Orr
L. a. virginianus Harlan
L. a. washingtonii Baird.
ORDER :
Lagomorpha
CLASS :
Mammal
FEDERAL LEGAL STATUS :
None [84]
OTHER STATUS : Information on state- and province-level protection status
of animals in the United States and Canada is available at NatureServe,
although recent changes in status may not be included.
WILDLIFE DISTRIBUTION AND OCCURRENCE
WILDLIFE SPECIES: Lepus americanus
GENERAL DISTRIBUTION :
Snowshoe hares occur from Newfoundland east to western Alaska; south in
the Sierra Nevada to central California; in the Rocky Mountains to
southern Utah and northern New Mexico; and in the Appalachian Mountains
to North Carolina and Tennessee [9,18,20,38].
Locations of subspecies are as follows [38]:
Lepus americanus americanus - Ontario, Manitoba, Saskatchewan, Alberta,
Montana, and North Dakota
L. a. cascadensis - British Columbia and Washington
L. a. columbiensis - British Columbia, Alberta, and Washington
L. a. dalli - Mackenzie District, British Columbia, Alaska, Yukon
Territory
L. a. klamathensis - Oregon and California
L. a. oregonus - Oregon
L. a. pallidus - British Columbia
L. a. phaeonotus - Ontario, Manitoba, Saskatchewan, Michigan, Wisconsin, and
Minnesota
L. a. pineus - British Columbia, Idaho, and Washington
L. a. seclusus - Wyoming
L. a. struthopus - Newfoundland, Nova Scotia, New Brunswick, Prince Edward
Island, Quebec, and Maine
L. a. tahoensis - California, western Nevada
L. a. virginianus - Ontario, Quebec, Maine, New Hampshire, Vermont,
Massachusetts, Pennsylvania, Ohio, and Tennessee
L. a. washingtonii - British Columbia, Washington, and Oregon
ECOSYSTEMS :
FRES10 White-red-jack pine
FRES11 Spruce-fir
FRES18 Maple-beech-birch
FRES19 Aspen-birch
FRES20 Douglas-fir
FRES21 Ponderosa pine
FRES22 Western white pine
FRES23 Fir-spruce
FRES24 Hemlock-Sitka spruce
FRES25 Larch
FRES26 Lodgepole pine
FRES27 Redwood
FRES28 Western hardwoods
STATES :
| AK |
AR |
CA |
CO |
CT |
ID |
KY |
ME |
MD |
MA |
| MI |
MN |
MT |
NV |
NH |
NM |
NY |
NC |
ND |
OR |
| PA |
RI |
SD |
TN |
UT |
VT |
VA |
WA |
WV |
WI |
WY |
| AB |
BC |
MB |
NB |
NF |
NT |
NS |
ON |
PE |
PQ |
| SK |
YK |
BLM PHYSIOGRAPHIC REGIONS :
1 Northern Pacific Border
2 Cascade Mountains
4 Sierra Mountains
5 Columbia Plateau
8 Northern Rocky Mountains
9 Middle Rocky Mountains
10 Wyoming Basin
11 Southern Rocky Mountains
12 Colorado Plateau
15 Black Hills Uplift
16 Upper Missouri Basin and Broken Lands
KUCHLER PLANT ASSOCIATIONS :
K001 Spruce-cedar-hemlock forest
K002 Cedar-hemlock-Douglas-fir forest
K003 Silver fir-Douglas-fir forest
K004 Fir-hemlock forest
K008 Lodgepole pine-subalpine forest
K012 Douglas-fir forest
K015 Western spruce-fir forest
K015 Western spruce-fir forest
K014 Grand fir-Douglas-fir forest
K020 Spruce-fir-Douglas-fir forest
K022 Great Basin pine forest
K028 Mosaic of K002 and K026
K093 Great Lakes spruce-fir forest
K094 Conifer bog
K095 Great Lakes pine forest
K096 Northeastern spruce-fir forest
K097 Southeastern spruce-fir forest
K099 Maple-basswood forest
K102 Beech-maple forest
K013 Cedar-hemlock-pine forest
K016 Eastern ponderosa forest
K017 Black Hills pine forest
K018 Pine-Douglas-fir forest
SAF COVER TYPES :
1 Jack pine
5 Balsam fir
12 Black spruce
13 Black spruce-tamarack
15 Red pine
16 Aspen
17 Pin cherry
18 Paper birch
19 Gray birch-red maple
20 White pine-northern red oak-red maple
21 Eastern white pine
22 White pine-hemlock
23 Eastern hemlock
24 Hemlock-yellow birch
25 Sugar maple-beech-yellow birch
30 Red spruce-yellow birch
31 Red spruce-sugar maple-beech
32 Red spruce
33 Red spruce-balsam fir
34 Red spruce-Fraser fir
35 Paper birch-red spruce-balsam fir
37 Northern white-cedar
38 Tamarack
51 White pine-chestnut oak
107 White spruce
201 White spruce
202 White spruce-paper birch
204 Black spruce
205 Mountain hemlock
206 Engelmann spruce-subalpine fir
207 Red fir
208 Whitebark pine
209 Bristlecone pine
210 Interior Douglas-fir
212 Western larch
216 Blue spruce
218 Lodgepole pine
219 Limber pine
217 Aspen
221 Red alder
223 Sitka spruce
224 Western hemlock
225 Western hemlock-Sitka spruce
226 Coastal true fir-hemlock
227 Western redcedar-western hemlock
228 Western redcedar
229 Pacific Douglas-fir
230 Douglas-fir-western hemlock
231 Port-Orford-cedar
243 Sierra Nevada mixed conifer
251 White spruce-aspen
253 Black spruce-white spruce
254 Black spruce-paper birch
252 Paper birch
256 California mixed subalpine
SRM (RANGELAND) COVER TYPES :
203 Riparian woodland
409 Tall forb
411 Aspen woodland
421 Chokecherry-serviceberry-rose
PLANT COMMUNITIES :
Snowshoe hares are primarily found in boreal forests and upper montane
forests; within these forests they favor habitats with a dense shrub
layer. In the Pacific Northwest snowshoe hares occupy diverse habitats
including mature conifers (mostly Douglas-fir [Pseudotsuga menziesii]
and variants), immature conifers, alder (Alnus spp.)/salmonberry (Rubus
spectabilis), Sitka spruce (Picea sitchensis)/salal (Gaultheria
shallon), and cedar (Thuja spp.) swamps [53]. In western Oregon
snowshoe hares were present in brush patches of vine maple (Acer
circinatum), willows (Salix spp.), rhododendrons (Rhododendron spp.),
and other shrubs [2].
In Utah snowshoe hares used Gambel oak (Quercus gambelli) in the
northern portion of the Gambel oak range [39].
In the Southwest the southernmost populations of snowshoe hares occur in
the Sangre de Cristo Mountains, New Mexico, in subalpine scrub: narrow
bands of shrubby and prostrate conifers at and just below timberline
that is usually composed of Engelmann spruce (Picea engelmannii),
bristlecone pine (Pinus aristata), limber pine (P. flexilis), and/or
common juniper (Juniperus communis) [12].
In Minnesota snowshoe hares use jack pine (P. banksiana) uplands, edges,
tamarack (Larix laricina) bogs, black spruce (Picea mariana) bogs, and
sedge (Carex spp.), alder, and scrub fens [62].
In New England snowshoe hares favor second-growth aspen (Populus
spp.)-birch (Betula spp.) near conifers, but other forest types occupied
by snowshoe hares include aspens, paper birch (B. papyrifera), northern
hardwoods, red maple (A. rubrum), balsam fir (Abies balsamea), red
spruce (Picea rubens)-balsam fir, eastern hemlock (Tsuga canadensis),
northern red oak (Quercus rubra), oak (Quercus spp.)-pine (Pinus spp.),
eastern white pine (P. strobus)-northern red oak-red maple, and eastern
white pine. Snowshoe hares also use shrub swamps dominated by
buttonbush (Cephalanthus occidentalis), alders, and silky dogwood
(Cornus ammomum) [20,21]. Further details on plant communities used by
snowshoe hares in different regions are in Bittner and Rongstad [9].
BIOLOGICAL DATA AND HABITAT REQUIREMENTS
WILDLIFE SPECIES: Lepus americanus
TIMING OF MAJOR LIFE HISTORY EVENTS :
Diurnal Activity: Snowshoe hares are crepuscular to nocturnal. They
are shy and secretive and spend most of the day in shallow depressions,
called forms, scraped out under clumps of ferns, brush thickets, and
downed piles of timber. They occasionally use the large burrows of
mountain beavers (Aplodontia rufa) as forms. Diurnal activity level
increases during the breeding season. Juveniles are usually more active
and less cautious than adults [53].
Breeding Season: Snowshoe hares are active year-round. The breeding
season for hares is stimulated by new vegetation and varies with
latitude, location, and yearly events (such as weather conditions and
phase of showshoe hare population cycle) [9,35]. Breeding generally
begins in late December to January and lasts until July or August
[35,53]. In northwestern Oregon male peak breeding activity (as
determined by testes weight) occurs in May and is at the minimum in
November. In Ontario the peak is in May and in Newfoundland the peak is
in June. Female estrus begins in March in Newfoundland, Alberta, and
Maine, and in early April in Michigan and Colorado. First litters of
the year are born from mid-April to May [9].
Gestation and Litter Size: The gestation period is 35 to 40 days; most
studies report 37days as the average length of gestation. Litters
average three to five leverets depending on latitude, elevation, and
phase of population cycle, ranging from one to seven [9,53]. Deep
snowpack increases the amount of upper-branch browse available to
snowshoe hares in winter and therefore has a positive relationship with
the nutritional status of breeding adults. Litters are usually smaller
in the southern sections of snowshoe hare range since there is less
snow. Newborn snowshoe hares are fully furred, open-eyed, and mobile.
They leave the natal form within a short time after birth, often within
24 hours. After leaving the birthplace siblings stay near each other
during the day, gathering once each evening to nurse [9,53]. Weaning
occurs at 25 to 28 days except for the last litter of the season which
may nurse for 2 months or longer [64].
Pregnancy Rate and Productivity: Female snowshoe hares can become
pregnant anytime after the 35th day of gestation. The second litter can
therefore be conceived before the first litter is born (snowshoe hares
have twin uteri) [9]. Pregnancy rates ranged from 78 to 100 percent for
females during the period of first litter production, 82 to 100 percent
for second litters, and for the periods of third and fourth litters
pregnancy rates vary with population cycle [17]. In Newfoundland the
average number of litters per female per year ranged from 2.9 to 3.5,
and in Alberta the range was from 2.7 to 3.3 [9]. The number of litters
per year varies with phase of population cycle (see below). In Alberta
the average number of litters per year was almost 3 just after a
population peak and 4 just after the population low [17]. Females
normally first breed as 1-year-olds. Juvenile breeding is rare and has
only been observed in females from the first litter of the year and only
in years immediately following a low point in the population cycle [9].
Mortality: In Yukon Territory 30-day survival of radio-tagged leverets
was 46 percent, 15 percent, and 43 percent for the first, second, and
third litter of the year, respectively. There were no differences in
mortality in plots with food added. The main proximate cause of
mortality was predation by small mammals including red squirrels
(Tamiasciurus hudsonicus) and arctic ground squirrels (Spermophilus
parryii). Littermates tended to live or die together more often than by
chance. Individual survival was negatively related to litter size and
positively related to body size at birth. Litter size is negatively
correlated with body size at birth [57].
Population Cycles: Northern populations of snowshoe hares undergo
cycles that range from 7 to 17 years between population peaks. The
average time between peaks is approximately 10 years. The period of
abundance usually lasts for 2 to 5 years followed by a population
decline to lower numbers or local scarcity. Areas of great abundance
tend to be scattered [36,53]. Populations do not peak simultaneously in
all areas, although there is a great deal of synchronicity in northern
latitudes [3]. From 1931 to 1948 the cycle was synchronized within 1 or
2 years over most of Canada and Alaska, despite differences in predators
and food supplies [68]. In central Alberta low snowshoe hare density
occurred in 1965 with 42 to 74 snowshoe hares per 100 acres (40 ha).
The population peak occurred in November 1970 with 2,830 to 5,660
snowshoe hares per 100 acres (40 ha) [44]. In the southern parts of its
range snowshoe hare populations do not fluctuate radically [46].
Exclosure experiments in Alberta indicated that browsing by snowshoe
hares during population peaks has the greatest impact on palatable
species, thus further reducing the amount of available foods. In this
study there was insufficient nutritious young browse available to
sustain the number of snowshoe hares present in the peak years (1971 and
1972) in winter [61].
PREFERRED HABITAT :
A habitat suitability index model for snowshoe hare was summarized by
Carreker [16]. Major variables in habitat quality include average
visual obstruction and browse biomass. Snowshoe hares prefer young
forests with abundant understories. The presence of cover is the
primary determinant of habitat quality for snowshoe hares and is more
significant than food availability [16] or species composition [19,51].
Species composition does, however, influence population density; dense
softwood understories support greater snowshoe hare density than
hardwoods because of cover quality. In Maine it was observed that
female snowshoe hares were more common on sites with less cover but more
nutritious forage; males tended to be found on sites with heavier cover
[50].
Winter browse availability depends on height of understory brush and
winter snow depth; 6- to 8-foot tall (1.8-2.4 m) saplings with narrow
stem diameters are required for winter browse in heavy snow [81].
In northern regions snowshoe hares occupy conifer and mixed forests in
all stages of succession, but early successional forests foster peak
abundance. Deciduous forests are usually occupied only in early stages
of succession [36]. In New England snowshoe hares preferred
second-growth deciduous, coniferous, and mixed woods with dense brushy
understories; snowshoe hares appear to prefer shrubby old-field areas,
early- to mid-successional burns, shrub-swamps, bogs, and upper montane
krumholz vegetation [21]. In Maine snowshoe hares were more active in
clearcut areas than in partially cut or uncut areas. Sapling densities
were highest on 12- to 15-year-old plots; these plots were used more
than younger stands [55]. In northern Utah snowshoe hares occupied all
the later stages of succession on quaking aspen and spruce-fir but were
not observed in meadows [66]. In Alberta snowshoe hares use upland
shrub-sapling stages of regenerating aspens (either postfire or
postharvest) [82]. In British Columbia overstocked juvenile lodgepole
pine (Pinus contorta) stands formed optimal snowshoe hare habitat [72].
In western Washington most unburned, burned, or scarified clearcuts will
normally be fully occupied by snowshoe hares within 4 to 5 years as
vegetation becomes dense [15]. In older stands (more than 25 years)
stem density begins to decline and cover for snowshoe hares decreases
[46]. However, in north-central Washington snowshoe hares may not
colonize clearcuts until 6 or 7 years and it may take 20 to 25 years for
snowshoe hare density to reach maximum [6]. Winter snowshoe hare pellet
counts were highest in 20-year-old lodgepole pine stands, lower in older
lodgepole stands, and lowest in spruce-dominated stands [46]. In
western Oregon snowshoe hares were abundant only in early successional
stages including stable brushfields [2]. In west-central Oregon an
old-growth Douglas-fir forest was clearcut and monitored through 10
years of succession. A few snowshoe hares were noted in adjacent virgin
forest plots; they represented widely scattered, sparse populations.
One snowshoe hare was observed on the disturbed plot 2.5 years after it
had been clearcut and burned; at this stage ground cover was similar to
that of the uncut forest. By 9 years after disturbance snowshoe hare
density had increased markedly [33].
Slope and Aspect: In western Washington snowshoe hares routinely used
steep slopes where cover was adequate; most studies, however, suggest
that snowshoe hares tend to prefer gentle slopes [15].
Moonlight increases snowshoe hare vulnerability to predation,
particularly in winter. Gilbert and Boutin [34] presented some evidence
that snowshoe hares tend to avoid open areas during bright phases of the
moon and during bright periods of a single night. Snowshoe hare
activity usually shifts from coniferous understories in winter to
hardwood understories in summer [56].
Home Range: Vegetative structure plays an important role in the size of
snowshoe hare home ranges. Snowshoe hares wander up to 5 miles (8 km)
when food is scarce [3]. In Montana home ranges are smaller in brushy
woods than in open woods [1]. In Colorado and Utah the average home
range of both sexes was 20 acres (8.1 ha) [25]. On Montreal Island of
Quebec, the average daily range for both sexes was 4 acres (1.6 ha) in
old-field mixed woods [8]. In Montana the home range averaged 25 acres
(10 ha) for males and 19 acres (7.6 ha) for females [1]. In Oregon the
average snowshoe hare home range was 14.6 acres (5.9 ha) [58].
COVER REQUIREMENTS :
Snowshoe hares require dense, brushy, usually coniferous cover; thermal
and escape cover are especially important for young snowshoe hares
[20,35]. Low brush provides hiding, escape, and thermal cover. Heavy
cover 10 feet (3 m) above ground provides protection from avian
predators, and heavy cover 3.3 feet (1 m) tall provides cover from
terrestrial predators [16]. Overwinter survival of snowshoe hares
increases with increased cover [51]. A wide variety of habitat types
are used if cover is available. Base visibility in good snowshoe hare
habitat ranges from 2 percent at 16.5 feet (5 m) distance to 0 percent
at 66 feet (20 m). Travel cover is slightly more open, ranging from
14.7 percent visibility at 16.5 feet (5 m) to 2.6 percent at 66 feet (20
m) [16]. Wolfe and others [81] reported that areas with horizontal
vegetation density of 40 to 100 percent at 50 feet (15 m) are adequate
snowshoe hare habitat in Utah [80].
FOOD HABITS :
Snowshoe hares eat a variety of plant materials. Forage type varies
with season. Succulent green vegetation is consumed when available from
spring to fall; after the first frost buds, twigs, evergreen needles,
and bark form the bulk of snowshoe hare diets until spring greenup
[9,53].
Winter Foods: Snowshoe hares prefer branches, twigs, and small stems up
to 0.25 inch (6.3 mm) diameter; larger stems are sometimes used in
winter [35]. In Yukon Territory snowshoe hares normally eat
fast-growing birches and willows and avoid spruce. At high snowshoe
hare densities, however, the apical shoots of small spruce are eaten
[68]. The snowshoe hare winter diet is dominated by bog birch (Betula
glandulosa) which is preferred but not always available. Greyleaf
willow (Salix glauca) is eaten most often when bog birch is not
available. Buffaloberry (Shepherdia canadensis) is the fourth most
common diet item. White spruce (Picea glauca) is eaten but not
preferred. In Alaska spruce, willows, and alders comprise 75 percent of
snowshoe hare diets; spruce needles make up nearly 40 percent of the
diet [79]. In northwestern Oregon winter foods include needles and
tender bark of Sitka spruce, Douglas-fir, and western hemlock (Tsuga
heterophylla); leaves and green twigs of salal; buds, twigs, and bark of
willows; and green herbs [53]. In north-central Washington willows and
birches are not plentiful; snowshoe hares browse the tips of lodgepole
pine seedlings [47]. In Utah winter foods include Douglas-fir, willows,
snowberry (Symphoricarpos spp.), maples, and serviceberry (Amelanchier
spp.). In Minnesota aspens, willows, hazelnut (Corylus spp.), ferns
(Pteridophyta spp.), birches, alders, sumacs (Rhus spp.), and
strawberries (Fragaria spp.) are winter foods. In New York winter foods
include eastern white pine, red pine (Pinus resinosa), white spruce,
paper birch, and aspens [52]. In Ontario sugar maple (Acer saccharum),
striped maple (A. pensylvanicum), red maple, other deciduous species,
northern white-cedar (T. occidentalis), balsam fir, beaked hazelnut (C.
cornuta), and buffaloberry were heavily barked [22]. In New Brunswick
snowshoe hares consumed northern white-cedar, spruces, American beech
(Fagus grandifolia), balsam fir, mountain maple (A. spicatum), and many
other species of browse [74]. In Newfoundland paper birch is preferred
[24]. Further details on regional food preferences are summarized in
Bittner and Rongstad [9].
Spring, Summer, and Fall Foods: In Alaska snowshoe hares consume new
leaves of blueberries (Vaccinium spp.), new shoots of field horsetails
(Equisetum arvense), and fireweed (Epilobium angustifolium) in spring.
Grasses are not a major item due to low availability associated with
sites that have adequate cover. In summer leaves of willows, black
spruce, birches, and bog Labrador tea (Ledum groenlandicum) are also
consumed. Black spruce is the most heavily used and the most common
species in the area. Pen trials suggest that black spruce is not
actually preferred. Roses (Rosa spp.) were preferred but a minor
dietary item as they were not common in the study area [79]. In
northwest Oregon summer foods include grasses, clovers (Trifolium spp.),
other forbs, and some woody plants including Sitka spruce, Douglas-fir,
and young leaves and twigs of salal [53]. In Minnesota aspens, willows,
grasses, birches, alders, sumacs, and strawberries are consumed when
green [52]. In Ontario summer diets consist of clovers, grasses, and
forbs [22].
PREDATORS :
The snowshoe hare is a major prey item for a number of predators. Major
predators include lynx (Lynx lynx), bobcats (L. rufus), fishers (Martes
pennanti), American martens (M. americana), long-tailed weasels (Mustela
frenata), minks (M. vison), foxes (Vulpes and Urocyon spp.), coyote
(Canis latrans), domestic dogs (C. familiaris), mountain lions (Felis
concolor), domestic cats (F. catus), great horned owls (Bubo
virginianus), barred owls (Strix varia), spotted owls (S.
occidentalis), other owls, red-tailed hawks (Buteo jamaicensis),
northern goshawks (Accipiter gentilis), other hawks (Buteonidae), golden
eagles (Aquila chryseatos), and crows and ravens (Corvidae)
[9,16,35,53,59,75]. Other predators include northern short-tailed
shrews (Blarina brevicaula) and black bears (Ursus americanus) [9,75].
In Glacier National Park snowshoe hares are a prey item of Rocky
Mountain wolves (Canis lupus irremotus) [40].
MANAGEMENT CONSIDERATIONS :
The snowshoe hare is an economically important species; its economic
impact varies with season, region, and population cycle [9]. It is
important prey for many furbearers (coyote, foxes, fishers, etc.), but
does not itself produce economically important fur. Its importance as
prey creates secondary effects during population lows; predators seeking
other food sources often increase predation rates on preferred game
species such as ruffed grouse (Bonasa umbellus) [42]. The snowshoe hare
is a small game animal and is important as human food in some remote
areas [3]. It is a pest in tree plantations [53] and causes damage to
both managed and unmanaged conifer stands in the Pacific Northwest [35].
Importance as Prey: Management of furbearers and sensitive predator
species is often dependent on snowshoe hare management as they are a
major prey item for many carnivores. Lynx, considered a sensitive
species in Washington, can be maintained only with management for their
main prey, the snowshoe hare. In north-central Washington a patchwork
of early successional stands favored by snowshoe hares and old-growth
forest needed by lynx for denning is recommended [83]. Logging and
thinning units of less than 40 acres (16 ha) encourage natural forest
regeneration; it is recommended that management units be greater than 20
to 25 acres (8-10 ha) (i.e., larger than the average snowshoe hare home
range) to encourage snowshoe hare use and thus benefit lynx [47]. In
Alberta winter coyote density is directly related to snowshoe hare
abundance. Coyotes switch to alternate prey species only when snowshoe
hares become relatively scarce [76].
Black and others [10] surveyed animal damage to conifer plantations in
Oregon and Washington based on data obtained from 1963 to 1975.
Snowshoe hare damage was substantial to Douglas-fir plantations; in many
cases tree damage was second only to that caused by mule deer
(Odocoileus hemionus). It must be noted that snowshoe hare populations
peaked in 1971 and 1972. During population lows most damage to conifer
plantations consists of clipping of small-diameter stems, twigs, and
branches. Barking becomes serious at high snowshoe hare densities [35].
Snowshoe hare damage birch seedlings by clipping twigs, terminal shoots,
and stems, or by gnawing bark and partially or completely girdling trees
[41].
Control: All direct control methods are effective only in the short
term. Lethal control methods are subject to state and local
regulations. Shooting snowshoe hares is costly of time and personnel,
and is not always effective. Trapping is costly. Toxic baits are not
always legal. Nonlethal methods include repellents, which can be
effective but costly, and exclusion fencing, which is also costly
[27,35].
Indirect control of snowshoe hares consists of habitat management to
reduce cover. Silvicultural practices can be modified to reduce
snowshoe hare use of an area; brushy areas attract snowshoe hares.
Second-growth stands with dense brushy understories and high sapling
densities are optimum snowshoe hare habitat. Thinning often creates
good snowshoe hare habitat when it encourages denser growth of shrubs
[35]. Snowshoe hares also favor clearcut blocks adjacent to pole-size
timber; edges are the areas of greatest snowshoe hare activity [35].
In British Columbia population density and recruitment of snowshoe hares
increased significantly in thinned stands of lodgepole pine during the
first winter but declined thereafter. Thinning overstocked lodgepole
pine had little or no effect on reproduction or survival of snowshoe
hares but reduced average body weights [72]. In aspen-birch stands
reduction of coniferous cover in cutover areas reduces use by snowshoe
hares [41]. Evans [27] suggested that snowshoe hare damage is probably
reduced where slash and brush are disposed of by burning. In quaking
aspen (Populus tremuloides) stands in Alberta, intensive regeneration
and periodic removal of competing brush promotes fast early growth and
reduces snowshoe hare damage [26]. Other recommendations include timing
conifer plantation establishment during the low phase of the snowshoe
hare population cycle, using larger planting stock with a reduced
fertilizer regime, and selection of tree species based on snowshoe hare
preferences [35,71,72].
The possibility of raising Douglas-fir stock that is less palatable to
snowshoe hares has been discussed [23].
Parasites and diseases of snowshoe hares have been studied extensively
and were summarized by Bittner and Rongstad [9].
FIRE EFFECTS AND USE
WILDLIFE SPECIES: Lepus americanus
DIRECT FIRE EFFECTS ON ANIMALS :
Severe fire can kill small mammals but adult snowshoe hares are probably
able to escape most fires. In central Alberta pre- and postfire population
estimates indicated that there was little or no direct mortality caused
by a severe to moderately severe June 1964 fire. No snowshoe hare
carcasses were found in an immediate postfire sweep of the area even
though a few dead voles (Microtus spp.) were found (presence of vole
carcasses indicated that showshoe hare carcasses would not have been
completely consumed by fire). Following a severe fire in 1968 two adult
snowshoe hares were flushed from blackened and smoldering areas but the
snowshoe hares left the burned site shortly afterward [43].
Komarek [48] compiled a table of observations of wildlife response to
fire. He listed snowshoe hares as attracted to fire and smoke, present
on black burns (snowshoe hares have been observed consuming ash and
char), and present on newly greened burns. In the Northwest Territories
snowshoe hares used a burn (severe fire in August 1981) the first winter
after fire; black spruce with bark charred by the fire were girdled by
snowshoe hares. Snowshoe hares ate charred black spruce bark on burned
plots but did not consume bark on unburned plots. Small black spruce
were preferred over large-stemmed trees. Use of the burned areas was
higher than use of adjacent unburned areas. (A laboratory test of
heated black spruce bark indicated that it is lower in resins and waxes
(unpalatable substances) than unheated controls.) By 1982 and 1983
there was little new growth and much exposed mineral soil [70].
Snowshoe hares often abandon fresh burns if cover is sparse and
nutritious browse is available elsewhere. In Alberta quaking aspen
stands with a history of recurrent fire supported a moderate snowshoe
hare population. A severe fire in May 1968 killed all aboveground
vegetation. Snowshoe hares completely avoided the severely burned area
until April 1969 after quaking aspen and balsam poplar had established
[43]. Freshly burned clearcuts are poor snowshoe hare habitat; however,
older brushy areas are desirable. In west-central Oregon old-growth
stands of Douglas-fir were clearcut and burned. Snowshoe hares were not
present on the burned area the first year after the fire [32].
Burns are increasingly occupied by snowshoe hares as plant succession
progresses. In central Alberta a severe 1968 fire was not appreciably
green until summer of 1969. Snowshoe hare population density on the
moderately burned and unburned areas increased after the fire, largely
due to an influx of the snowshoe hares from the severely burned sites.
By late summer of 1969 snowshoe hare runways were common and well used
in the severely burned areas [43]. In the September following a July
1971 wildfire (Alaska), snowshoe hares consumed nearly all the postfire
willow sprouts. During the winter of 1971-1972 (a snowshoe hare
population high in Alaska) snowshoe hares consumed large quantities of
charred bark (spruce, aspens, and birches). The second winter after the
fire snowshoe hares consumed all of the aspen sucker regrowth in several
stands. During the 2 years following the fire 100 percent of available
hardwood browse was consumed in the unburned control. The snowshoe hare
population declined from 1972 to 1974 in both the burned and unburned
plots. Snowshoe hares were not observed on the burned plots from 1974
to 1976, the last year reported [77].
HABITAT RELATED FIRE EFFECTS :
Nearly every plant that is important to snowshoe hares is favored by
fire: jack pine, lodgepole pine, black spruce, quaking aspen, birches,
blueberries, fireweed, eastern white pine, white spruce, northern
white-cedar, tamarack, and eastern hemlock are all fire followers to
some extent and are used by snowshoe hares for food and/or cover [36].
Fire, even at moderatly long intervals, maintains a mosaic of
successional stages which provide good snowshoe hare habitat [65]. In
summer forbs and the leaves of shrubs are abundant and nutritious on
recently burned areas [45]. Snowshoe hares depend on small, new stems
which are available in large amounts on recently burned areas [36]. In
Alaska small fires or large fires with unburned areas of black spruce or
other heavy cover provide good to optimal habitat for snowshoe hares
[45]. In Alaska a 3-year-old burn provided willow browse for snowshoe
hares [78]. In north-central Washington fire suppression has limited
the amount of early-successional forest. The prevalence of older,
suboptimal habitats does not provide enough browse for snowshoe hare
populations to sharply increase and therefore snowshoe hare populations
in the area are low but stable [46].
Periodic fire that results in an increase in dense, brushy cover is
beneficial to snowshoe hares. In Minnesota a large prescribed fire set
in 1925 escaped and burned a few thousand acres. The area was seeded in
by jack pine which, after eleven growing seasons, supported a large
snowshoe hare population [36]. Snowshoe hares populations have
increased after fire in Acadia National Park, Maine [60].
Areas that are burned frequently enough to reduce the height and density
of brushy cover would not be used much by snowshoe hares. In
northwestern Minnesota mature quaking aspen stands were converted to
open brushlands with repeated prescribed fires over a 17-year period.
Study plots were burned in spring 1968, 1971, 1973, and 1975. The
number of snowshoe hare pellets counted fluctuated with burning;
snowshoe hare pellets decreased immediately following fire and gradually
increased until the next fire. After the fourth fire snowshoe hare
numbers and rate of increase were both very low [4]. Mean frequency of
snowshoe hare observations was higher on control areas (48%) than on
burned areas (33%). After 1973 ground cover was sparse on burned areas
[5].
FIRE USE :
Prescribed fire could be used to improve snowshoe hare habitat by
creating openings and early successional habitat. Fire at less than 5-
to 10-year intervals may result in repeated increases and decreases in
snowshoe hare populations [36].
FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find Fire Regimes".
References for species: Lepus americanus
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