Kris Buecking

Overview

The following report is a synthesis of the best available science regarding the biology of wolverines in North America, an outline of guidelines which have been proposed for their management, a review of current management practices, and, a critical analysis of how well these guidelines and policies reflect what is known about wolverines and their critical needs for survival. The text is organized into four parts:

• Part One: Biological Information
• Part Two: Management Guidelines
• Part Three: Management Policies
• Part Four: Recommendations

This document is intended to provide a comprehensive overview of both science and management issues related to wolverines. Only 9 field studies have been conducted to date in North America, with two of those studies currently underway and three others located in the Yukon and Alaska where environmental conditions and population dynamics differ significantly from the western United States and southern British Columbia. Wolverines are a wide ranging, solitary species that are considerably difficult and costly to study. As a result, our knowledge is limited, though growing. Recent scientific findings have begun to answer questions which will enable land managers to more appropriately incorporate wolverines in conservation and long-term planning strategies. Guidelines for conservative management policies to ensure future viability of this species emerge from the scientific literature. Unfortunately, few policies have been enacted that adequately address these issues, though some attempts are being made in Malheur and Sawtooth National Forests, as well as Idaho. While specific questions remain unanswered warranting continued field research efforts, the foundation of knowledge regarding wolverine behaviour is sufficient to move forward with clear, long-term, and long-range policies to ensure the future of this fascinating and important species is adequately protected.

Part One: Biological Information

Wolverine (Gulo gulo) is the largest terrestrial member of the weasel family Mustelidae, with subspecies Gulo gulo luscus specific to North America (Hash 1987, cited in PP petition). It is believed to have evolved from Eurasia, migrating to North America across the Bering Strait during the Pleistocene era (Irving 1972, cited in PP petition).

Appearance and Morphology

Wolverines are the largest terrestrial mustelid and have been likened to a small bear with a tail. Its head is broad and rounded with small eyes and short, rounded ears. They are sexually dimorphic, with males averaging 30% heavier and 10% longer than females (Hash 1987, cited in Butts 1992). Copeland (1996) found average weights for adults to be 27 lbs for males and 17 lbs for females. An Alaska study (Banci & Harstaed 1988) found weights averaging 31 lbs for males and 22 lbs for females. Wolverines have large feet adapted for snow travel, digging, and climbing with low foot loads that enable them to prey on large mammals in deep snow (Hash 1987, cited in Butts 1992). Each foot has five toes with semi-retractile claws that are sharply curved and measure 2-3 cm. Adult wolverine tracks are circular (8-9 cm long and 7-8 cm wide) with the third digit being longest in the hindfoot and the fourth being longest in the forefoot (Hash 1987, cited in Butts 1992).

Wolverine fur is black to medium brown, with a contrasting stripe from shoulder to flank which tends to be blonde to reddish-brown. Dense, woolly underfur (2-3 cm) is contrasted with coarse, stiff guard hairs (6-10 cm). Hair is short on the head, longer in back, with the tail long (15-20 cm) and shaggy. In winter, dense, stiff bristle-like hair between toes and pads of the feet. Wolverine fur has the ability to shed frost and ice. Colour can vary even within similar geographic areas (Banci 1994). There is sometimes a blonde band on the face from ear to eye and throat and chest though considerable variation in these markings have been found (Copeland 1996). White feet and digits in the front feet were common in Copeland’s (1996) study.

The skull of the wolverine is larger than other mustelids. Its structure enables crushing bones and feeding on frozen carrion in winter. Frequently broken incisors and canines on older wolverines were reported by Hash (1987, cited in Butts 1992). Thirty-eight teeth, similar to marten and fisher, are standard. Wolverines have poor eyesight but a highly developed sense of smell, reportedly able to detect carrion under 1-2 metres of snow.

Communication

Wolverines appear to communicate primarily through vocalisations and scent marking (Copeland & Hudak 1995). Anal and ventral glands emit odiferous secretions used in marking which plays an important role in carnivore social organization, though data on scent production and behavioural responses in Mustelidae is not well understood (Copeland 1996). Marking has been observed in the form of climbing a tree and depositing musk, scratching the ground, gnawing or biting a root or limb with musk, or depositing a scat or musk on the ground (Koehler et al 1980). In this same study, marking sites were identified as prominent trees with large diameters. Additionally, these authors suggest that instead of serving a territorial function of maintaining exclusive areas, marking for wolverines appears to aid in maintaining solitude through time rather than area spacing (Koehler et al 1980).

Reproduction

The breeding season of wolverine may extend from April through August with implantation being delayed (Wright et al 1955, cited in Copeland 1996) until sometime between November and January, with births then occurring from December through March, but primarily in January and February (Rausch et al 1972, cited in Banci 1994). Total gestation is from 215-272 days, with the period after implantation being 30-40 days (Mead 1981, cited in PP petition). Delayed implantation is hypothesized to allow birth to occur under optimal conditions, when food and denning sites are readily available (Banci 1994) and as early as possible in the spring to provide the greatest opportunity maturation before winter (Mead 1989). Another hypothesis suggests delayed implantation has evolved to limit population size when environmental conditions are not favourable for reproduction and rearing young (Mead 1989). This mechanism could limit reproductive success for female wolverines who experience human disturbance any time between breeding and implantation. Unfavourable environmental conditions have increasingly included human disturbance which could limit reproductive success for wolverines as a result of this mechanism. "The condition of females before implantation may be the most critical factor determining successful birth" (Banci 1994). This has significant implications concerning the timing of trapping seasons in different regions (see Management Section).

Sexual maturity is reached after two years, with wolverines beginning to breed in their second or third year (Banci et al 1988). Although it has been estimated that litters can range from 1 to 5 kits, with an average of 2 or 3 (Banci 1994), recent studies indicate that these numbers may be exaggerated. In Hornocker and Hash’s (1981) study in Montana, an adult female produced no young during the 3 years she was observed and only 50% of adult females were thought to be pregnant at any time in the 5 year study, indicating females did not produce young every year. Copeland (1996) found 2 females did not produce any kits in 2 years, 1 female produced 3 litters in 4 years, with an average reproductive rate for 4 adult females less than 1kit/female/year. More recently, in a British Columbia study (Krebs et al 1997), during 2 years of research, none of 7 adult females were found to be reproducing although 2 established dens and behaved in ways that are consistent with breeding females. In the year following, 2 of 6 females were observed with kits.

Newborn kits have fine, white fur, with closed eyes and unerupted teeth (Magoun 1976, cited in PP petition). Kits are weaned at 8 to 10 weeks (Krott 1960), coinciding with tooth eruption, and begin to leave the den at 12 to 14 weeks. After weaning, wolverines grow quickly and can reach adult size by 7 months of age (early winter) (Banci 1994). The sex ratio of wolverines appears to be equal at birth.

Mortality

The primary mortality factor for wolverines throughout most of its distribution is human predation through trapping, incidental catches, and poaching (Banci 1994). Travelling long distances and opportunistic scavenging natures increase vulnerability to trapping. Of 6 radio-collared animals that died during the B.C. study (Krebs et al 1997), 2 were trapped, 1 was killed on a highway, 1 was killed on a railway, 1 died of natural causes and 1 remained as unknown cause of death. It is a widely publicized fact that rare forest carnivores are negatively impacted by presence of roads through direct mortality (road kill) and through increased human disturbance resulting from improved access to wolverine habitat (Frederick 1991, Mychasiu et al 1988, Ruediger 1996). "The mere presence of any road in wildlife habitat has a potential for increasing contacts between animals and people...and even if the results are not lethal, repeated encounters are not necessarily desirable for the animals involved. ...whenever forest roads are built, modified animal behaviour and changes in habitat will lead to changes in wildlife population levels" (Lyon 1984, p. 6). Krebs et al (1997) identified the major transportation corridor that runs through the British Columbia study area as playing an important role as a mortality sink.

A recently published study, apparently the first of its kind, examines specifically the response of wolverines in winter to transportation corridors in Kicking Horse Pass area of British Columbia (Austin 1998). Avoidance for areas within 100m of the Trans Canada Highway and preference for areas greater than 1100m was found to be significant. Wolverines approaching the highway exhibited a consistent pattern of repeated approaches and retreats and only crossed 50% of the time. Where they did cross, the mean right-of-way was significantly narrower than that of sections where individuals approach but didn’t cross. Austin (1998) concluded that roads with narrow rights-of-way (<50m) may be more suitable for wolverine movements.

Starvation appears to be the next leading cause of death for wolverines, with predation also playing a role. Research findings in Yukon (Banci 1994) and Montana (Hornacker & Hash 1981) where starved animals were found, in spite of food being relatively abundant, suggests that a reduction in foraging ability due to injury, inefficiency, or lack of learned ability may play a role. Further, habitat fragmentation and increasing human presence may reduce the willingness or ability of wolverines to access available food sources (Butts 1992).

The role of predation on kits is not understood. Females go to extreme lengths to secure safe dens for their young which suggests that predation may be important (Krebs pers. comm.). Survivability in the wild is considered to be 8-11 years, though it has rarely exceeded that lower limit in Montana (Hornacker et al 1981). Transient juvenile males and females with young are more vulnerable to trapping than adult males with established home ranges. Young wolverines appear to remain close to their natal den for approximately 2 years and, therefore, may be more vulnerable to predation and human-disturbance related mortality (Copeland 1996).

Habitat

Wolverines tend to occupy large wilderness or backcountry areas with little human activity or development (Hash 1987). In the western U.S., habitat types fall into two general categories, Pacific coastal forest and Rocky Mountain forest (Hash 1987). The former consists primarily of western white pines, lodgepole pines, ponderosa pines, grand firs, Douglas firs, western hemlocks, Englemann spruces, red cedars, and western larches. The Rocky Mountain forest habitat is primarily composed of firs, pines, and larches, with trembling aspen and cottonwoods also present in some areas. Ecotonal areas, in addition to marshes, lakes, cliffs, and transition zones also appear to be important habitat components for this region. While particular plant associations do not appear to define wolverine habitat at the landscape level, the presence of abundant food supplies and large tracks of undisturbed wilderness are critical (Banci 1994). Banci also suggested that lowest densities of wolverines would likely be found in areas with lowest habitat diversity and prey abundance. In addition to avoiding humans, wolverines tend to avoid high temperatures, resulting in summer ranges at higher elevations and winter ranges at lower elevations.

Copeland’s (1996) Idaho study reported such distinct seasonal elevation shifts in addition to talus/rock cover being preferred during summer and montane coniferous forest cover preferred during winter. Douglas fir was also found to be preferred in summer and lodgepole pine favoured in winter. Reluctance to cross openings such as clearcuts or burned areas has been reported in Montana (Hornocker et al 1981). Idaho wolverines commonly crossed natural openings and areas with sparse overstory found in burned areas, meadows, and open mountain-tops (Copeland 1996). In a review of related literature, Butts’ (1992) reported no relocations in clearcuts. In B.C., Krebs et al (1997) reported habitat use differences between the sexes, where males spent more time in ICH (Interior Cedar Hemlock) zones and females were found proportionately more often in ESSF (Englemann Spruce Subalpine Fir) zones.

In the B.C. study area, a major transportation corridor (highway and railway) along the Illicilaewaet River appeared to define habitat boundaries and may entrench populations through disturbance displacement or direct mortality (Krebs et al 1997). "...Forest carnivores ...are especially vulnerable to road mortality since they have large home ranges that often include road crossings" (Baker et al, in press).

Denning habitat

Denning habitat may be the primary and most critical limiting factor for population viability of wolverines in Montana, Idaho, and British Columbia. "Even with adequate food, wolverines may not be resident without suitable denning habitat." (Copeland 1996, p. 72). Two types of dens appear to be used by females, one where young are born and raised while immobile (natal) and the other where kits are sheltered prior to weaning (maternal). Den sights in southern habitat ranges include caves, near uprooted trees, burrows, overhanging banks, snow tunnels, snow-covered tree roots, rocks and boulders, or logjams (Hash 1987). This indicates the importance of available snags and downed timber. Snow tunnels have been reported up to 60m in length (Pulliainen 1968, cited in Banci 1994). Dens above treeline appear to require snow from 1 to 3 m deep. More recent research indicates the importance of secluded high elevation cirque basins which females used for natal den sites (Copeland 1996). 2 marked females and 1 unmarked female in this same study used subalpine talus habitat for denning sites. "The availability of talus communities throughout Idaho may define limitations for wolverine reproductive potential" (Copeland 1996, p. 93). Coniferous riparian sites were used at lower elevations, characterized by dense shrub and regenerating understory and multiple layered downed timber.

In British Columbia, dens were found at approximately 5400 feet in elevation amidst old avalanche debris and also at 4600 feet under a large boulder within a talus slope/slide path. All sites appeared to have been used for more than one season and were located in remote, roadless valleys within the ESSF biogeoclimatic zone (Krebs et al 1997).

Female wolverines with kits near denning sights appear to be extremely sensitive to human disturbance. Copeland (1996) reports a mother wolverine moving one then a second kit away from her den upon discovering researchers’ snowshoe tracks. Other studies (Pulliainen 1968, Krott 1960, Myrberget 1968) also report den abandonment as a result of human disturbance. The movement of kits to less suitable habitat as a result of interface with winter recreationists may result in detrimental energy expenditures, stress, susceptibility to predation, exposure, competition for den sights, or other negative impacts.

Home Ranges and Dispersal

Wolverines travel long distances and reportedly occupy large home ranges. In Alaska, males were found to occupy average home ranges of 257 sq. miles while females maintained 36 sq. miles (Magoun 1985, cited in PP petition). Hornocker and Hash (1981) found wolverines in Montana to occupy 163 sq. miles for males and 150 sq. miles for females. In Idaho, Copeland (1996) reported average home ranges to be 175 sq. miles for females and 719 sq. miles for males. In British Columbia, home range sizes fell with those recorded in previous studies. These animals have extraordinary stamina for travelling long and sustained distances over rough terrain and deep snow. Individuals have been known to cover 40 miles without rest while being pursued (Wilson 1982, cited in PP petition). Much of this travel involves searching for carrion and other food supplies, although male home ranges are also influenced by the presence of females during mating season. Availability accounts for home range sizes, with areas of scarce resources leading to larger recorded home ranges, such as Northwest Alaska in winter (Banci 1994). Females typically have smaller home ranges as the presence of young restricts their movements. Their home range size reflects the minimum size necessary to obtain food for survival more than those of males. Because of the restrictions of kits, females may use a localized, low-maintenance foraging strategy that minimizes risks to young. Males’ coverage of larger distances in search of females for breeding contributes to larger home ranges and travelling distances. Winter and summer ranges usually overlap, with changes being attributable to prey distribution and availability (Banci 1994). Subadult home ranges reflect the transition before dispersal. Temporary long-distance movements unrelated to dispersal were recorded for both sexes in Montana (Hornocker et al 1981).

Juveniles do not seem to all disperse at the same age. Individuals that fail to establish permanent home ranges likely become transients, moving according to food availability and social pressures (Hatler 1989). This category of animals, as a result, has the largest home range size. Four males in Copeland’s (1996) study dispersed at sexual maturity, with two emigrating distances over 85 miles. Wolverines of different populations across large geographic areas are likely similar morphologically due to such widespread dispersal, since isolated gene pools are not able to be established. Dispersal involves increased vulnerability to starvation or predation and data on outcomes for dispersing individuals is scarce (Copeland 1996). Krebs (pers. comm., 1998) is studying movements of four juveniles that were collared June 1997 for survivorship and dispersal information. All four are males and degree of independence from their mothers appears varied.

Generally home ranges of opposite sexes overlap extensively, although partial overlap between same sexes occurs. The range of one male typically covers the ranges of 2 to 6 females (Banci 1987, cited in Banci 1994). The situation where same-sex wolverines tolerate the presence of one another more readily appears to be when abundant and concentrated sources of food are present. Density of an Idaho population has been estimated to be approximately 1/113 sq. miles. Estimates of density for Montana (Hornocker et al 1981) are 1/30 sq. miles.

In Montana, effects of human predation have been proposed to explain the extensive overlap of home ranges of both sexes and all ages (Hornacker & Hash 1981). This behavioural instability likely results from the removal of individuals before they have established particular ranges Hornacker & Hash 1981). In British Columbia, perhaps due to the larger population, females appear to have primarily exclusive ranges except for young of less than 2 years, though genetic information to confirm that two females with overlapping ranges are mother and daughter is pending (Krebs 1998, pers. comm.).

Food and Foraging Behaviour

Large mammal carrion has been identified as the primary source of food for wolverines (Banci 1995). "The availability of large mammals underlies the distribution, survival, and reproductive success of wolverines. They are primarily scavengers in the winter and opportunistic omnivores in summer, consuming prey that includes snowshoe hares, hoary marmots, ground squirrels, red squirrels, salmon, porcupine, mice and voles, and berries" (Banci 1994). Although wolverines are primarily scavengers, they can prey on large mammals under certain conditions (e.g. deep snow) that offers them an advantage. Caching food seems to occur, though the frequency and dependence on this method of food storage is unknown.

Females with young that are weaned but not yet hunting experience high demands to locate food using efficient foraging strategies. In B.C., Krebs et al (1998, pers. comm.) have observed the importance of hoary marmot as a dietary staple for females with young of the year and are attempting to map the distribution of this prey to understand the extent to which it determines spatial patterns and foraging behaviour.

PART 2: MANAGEMENT GUIDELINES

The following section attempts to synthesize proposed management guidelines according to two primary documents: The Scientific Basis for Conserving Forest Carnivores: American Marten, Fisher, Lynx, and Wolverine and Biology of the Wolverine in Central Idaho. Information from interview with field biologist John Krebs about possible recommended guidelines emerging from the Columbia Basin research project are also included. To identify the source of each bulleted statement, an abbreviation of the title will be provided (SBCFC, BWCI, and JKCB, respectively). These sources provide the most comprehensive overviews available of how science needs to be reflected in management policies. Other citations from biological section either make no recommendations or outline similar guidelines referred to below. Comments that are not cited or in bullets are provided by this author and are primarily extrapolated from scientific findings contained in Part One. This information is organized into the following sub-sections:

• Habitat
• Forestry
• Roads and Access
• Denning Habitat
• Human Disturbance/Development
• Mortality
• Prey/Foraging Needs

These proposed guidelines will be followed by an overview of current management practices established for Malheur National Forest, Idaho State Conservation Effort, and Sawtooth National Forest. A critical analysis of both the proposed guidelines and the current management practices will be presented in order to determine how well these measures address the necessary criteria for maintaining viable wolverine poplulations based on the best available science. As will be seen, even the most comprehensive proposed guidelines neglect important criteria. Further, while the policies outlined are important efforts to enact conservation practices for the benefit of wolverine populations, they are far from adequate. Recommendations for wolverine management will follow which reflect a comprehensive review of the best scientific literature available for this topic.

Habitat

Wolverines are a wide ranging species, therefore, in their daily movements and throughout their life, they are highly susceptible to being confronted with dwindling areas of remote wilderness safe for travel, foraging, denning, and meeting other basic survival needs.

Habitat loss and fragmentation are the primary causes of reduced or extirpated wolverine populations (Hornacker & Hash 1981, Magoun 1985, Banci 1994).

Availability of large undisturbed areas of remote wilderness appear critical for the maintenance of wolverine populations. Indirect evidence of species disappearing from areas with dense human populations supports this point.

• Structure, not vegetative type, of forested habitat is important for wolverine habitat. Adequate habitat for foraging, kit rearing, denning, and security in appropriate season must be available and secure from human disturbance (BWCI).
• The presence and stability of ecosystems with broad scale human influences absent is a life history requirement. Habitat alteration may isolate subpopulations and increase vulnerability to extinction (BWCI).
• Wolverines are wide ranging, therefore conservation programs need to transcend jurisdictional boundaries (SBCFC).
• Refugia may be one of the best means of ensuring persistence of wolverine populations, including representative appropriate vegetative types (SBCFC). (For Montana, this would be montane coniferous, moderate to high elevation habitat.)
• Adequate travel corridors connecting habitats that incorporate attributes which support self-sustaining populations may be important (SBCFC).
• The lower the wolverine density, the larger the refuge needed. Size for refuges may be estimated according to reproductive units-1 male and 2-6 females (SBCFC).
• Because of the size necessary for adequate refugia, wolverines would benefit from being part of a large carnivore conservation strategy established for grizzly bears, wolvers, or cougars (SBCFC).

Forestry and mining practices that reduce cover available, alter structure (forest and tallus/boulder) and, remove fallen timber are likely to negatively impact wolverine populations. Removal of suitable habitat for survival and reproductive needs and increased human access are possible direct effects that need to be mitigated through management policies.

• Complex, large structures in forested habitats (late-successional stands) are important. Logging and other land-use impacts may limit reproduction through habitat modification (SBCFC).
• Timber harvest should be managed to ensure maximum biological diversity over the long term with small cuts, down material, understory to support birds and small mammals, and travel corridors between areas which provide secure cover (Butts 1992).

"Substantial evidence suggests that roads and associated human development and activity negatively influence the movements of large and medium-sized carnivores" (Austin 1998)

With 378, 000 miles of officially accounted for road on 191 million acres of National Forest, the issue of probably negative impacts on wolverine populations is significant. Further, an estimated 60, 000 additional miles which are not included in government inventories exist (Williams, 1998). 70% of the short term and temporary roads on the Flathead National Forest in Montana failed to be included in Forest Service inventories (Hammer 1990). While wolverines appear willing to cross roads under certain conditions (Krebs 1998, Austin 1998), management guidelines need to address the issues of direct mortality, increased human access, human predation, attraction to road kill, and, fragmentation of habitat.

• Because wolverines are scavengers and naturally attracted to carrion, removal of road kill is an important management consideration (JKCB).
• The proposed highway twinning which is inevitable on the Transcanada highway which runs through this study area will require input in terms of inclusion of crossing structures at locations where wolverines appear to cross (JKCB).
• Secondary effects of forestry roads with respect to other predators gaining access to new areas, possibly contribute to increased predation mortality of wolverines (JKCB).

While these guidelines address some important issues regarding road access to wolverine habitat, they do not identify the more basic elements which can be inferred from the scientific literature. Roadless wilderness areas must be maintained, forestry roads on public lands need to be rehabilitated wherever possible, highway twinning at locations where wolverines may require crossing from one wilderness area to another must be restricted, and crossing structures which provide adequate cover and are established at narrow points of right-of-way must be provided.

Habitat: Denning Needs

Providing for the denning needs of female wolverines either pregnant or with kits appears to be the most critical factor for maintaining wolverine populations due to their low reproductive rate and high sensitivity to human disturbance. "Refugia may be most important in providing availabiliy and protection of reproductive denning habitat" (Copeland 1996). Sub-alpine cirque basins with small pockets of boulder/talus surrounded by forest cover provide winter denning sites for females. These share common attributes which winter recreationists find desirable. Management guidelines must incorporate restricted access in these areas across the landscape from November to February when potential disturbance is highest. The following guidelines partially address this need.

• Reproductive rates are low and sexual maturity delayed.
• Protection of natal denning habitat (subalpine cirque basins) from human disturbance is critical for persistence of wolverine in Idaho (BWCI).
• Improved accessibility of snow machines and increased interest in winter recreation has likely displaced wolverines from potential denning habitat and will continue to be a threat (BWCI).
• Coarse woody debris, large cavities, avalanche debris are important structures for den sites in some regions and therefore need to be maintained (SBCFC).
• Refugia may be most important in providing availability and protection of reproductive denning habitat (BWCI)

"Wolverines are usually associated with wilderness chiefly because they are so vulnerable to the activities of humans" (Banci, cited in Butts 1992).

This sub-section overlaps several of the others (forestry and resource extraction, mortality, roads and access) and, since all impacts on wolverine populations through habitat loss are a result of human disturbance, it is difficult to separate out. The issues pertinent to this section specifically relate to direct human disturbance through confrontation with den sites or individuals.

• Wolverines are difficult to observe, travel long distances, and occur at low densities, therefore information on population may not be accurate (e.g. increase in sightings may reflect greater human access not higher numbers). Determining effects of human disturbance is therefore difficult (SBCFC).
• Survivability of transients may be important to population and distributional dynamics, yet these individuals are at greater risk of mortality through direct or indirect contact with human disturbance and predation (SBCFC).
• Impact of recreationists in summer in alpine areas where wolverines may be mating needs to be considered. Managing access to mating and denning sites in summer and winter will help to minimize negative impacts (SBCFC).

"Direct anthropogenic mortality was considered by van Zyll de Jong (1975) as the most likely factor to have affected wolverine populations. Interactions with humans and human developments result in lower wolverine populations" (Austin 1998, p. 5).

• Trapping accounts for a high proportion of wolverine mortality (SBCFC).
• Areas protected from trapping must be established and possibly extended (SBCFC).

Trapping of wolverines is legal in Montana and British Columbia. In B.C., no quotas exist for individuals and harvests are regulated through seasonal closures. Estimated yearly harvests are currently at 100-125, however, they exceeded 550 for three consecutive years in the mid-1970’s (Krebs pers. comm.). In Montana, individual quotas are 1/year/trapper and seasonal closures also apply with hunting and trapping allowed from December 1-February 15. With population status unknown and estimates below those of lynx populations (Kennedy 1998), which are anticipated to be listed as Endangered in the near future, it is surprising that trapping is still legal in this region.

Prey/Foraging Ability

Excessive hunter harvest, loss of ungulate wintering areas, displacement of ungulate populations through excessive timber harvest or urbanizations may adversely affect wolverines as this is their primary food item (Copeland 1996).

Management practices need to protect ungulate carrion availability in order to maintain the necessary link between wolverines and ungulate presence. This importance of this guideline is well documented.

• Importance of hoary marmot population for females with young of the year from June to August (JKCB).
• Human activities which decrease large mammal populations may have negative impacts on wolverine populations (SBCFC).
• Management practices need to maintain presence and opportunity for carrion (BWCI).

The sub-sections above outline the guidelines that have been documented as necessary criteria for maintaining healthy populations of wolverines. While in combination they identify numerous key points which appear essential for developing the framework of a scientifically-based conservation strategy, no one document is comprehensive enough. Actual examples of management policies for Malheur and Sawtooth National Forests, and proposed conservation strategies for Idaho in addition to a draft prepared by the Western Forest Carnivore Committee, which attempt address the needs of this species are summarized and analyzed below.

PART THREE: MANAGEMENT POLICIES

Wolverine Habitat Guidelines for the Malheur National Forest

• Limit access to isolate from human activity (recreation use and resource management).
• Keep habitat fragmentation low to allow for unimpeded seasonal movement.
• Maintain/enhance winter range (time restrictions for management activities).
• Maintain mosaic of seral forest stages
• 30-50% >100years
• 25-35% 50-100years
• 15% 20-50years
• 10-15% openings (meadows, grass, seedlings)
• >50% cover-avoid large, created openings or young, dense stands-particularly across ridges and stream courses.
• Avoid fragmenting or isolating cliffs, talus, rock caves, swamps, meadows.
• Avoid lethal treatments to reduce mammal populations
• Maintain/enhance down, woody logs and material
• Connectivity-3-6 miles between core areas-include major stream/drainage features.

The guidelines established for the Malheur National Forest address several important criteria for wolverine conservation, including human disturbance, habitat fragmentation, structural composition of habitat, poison-control programs, and connectivity. This strategy, however, is disfunctionally vague and open to interpretation, except for the breakdown of seral forest stages which attempts to quantify structural composition more specifically. Several questions emerge including:

• To what extent, where, and by what means will human activity and access be limited?
• How is ‘low’ habitat fragmentation quanitified?
• How will winter range be enhanced?
• Is 100 year old timber as the maximum seral stage adequate for structural needs in the Northern Rockies?
• How was the size (3-6 miles) for connective corridors determined? Is this adequate? Location of these corridors (high elevation ridges, low forested passes) must be considered and necessary attributes contained within.

No mention is made of other important considerations such as road rehabilitation, maintaining roadless wilderness areas adequate for reproductive units, protection of ungulate species, road crossing structures, or restrictions specific to denning habitat. These guidelines provide a broad overview of several critical factors and provide a starting point for a management strategy. Defining each criteria more specifically and addressing these other issues would make this policy more comprehensive.

Sun Valley Heli Ski is required to meet the following mitigation measures to operate their heli-skiing activities in this region:

• avoid unnecessary skier transport and will not fly over any areas of concern when transporting skiers
• request approval from Forest Service in Owl Creek-Titus Peak area-trained wildlife biologists will verify presence
• SVHS will overfly areas of concern to look for presence
• overflights may be allowed infrequently when there is reasonable evidence that animals are not in area of concern
• areas of concern are those intermittently inhabited by wolverines and crucial to their survival
• SVHS and FS will gather and consider all available information concerning wintering areas, den locations, etc. through weekly wildlife observations
• shall not operate in or overly any areas with known wolverine natal dens
• SVHS will immediately report all sightings

"Although there may minor effect on individual animals, this project would not lead to the listing of any species as threatened or endangered."

These management guidelines were developed from the EA and public input and then further amended. As such, they outline the first attempt to restrict winter recreational activity for the purpose of wildlife protection that I am aware of in this region. Questions which emerge from this document include the following:

• What data will be used to identify areas of concern?
• What data exists to suggest spotting scopes are useful for locating wolverines?
• These guidelines depend heavily on regular data collected from the field...What about areas that are difficult to access for tracking but might be used by ski clients? Further, much of this data will be collected by SVHS employees-bias? training?
• What data was used to determine minimum flight distances to reduce disturbance?
• Based on available data...What about suspected sites that are difficult to confirm? It appears that regulations will only apply to known and proven sites which is difficult to establish and will likely not reflect what is actually happening on the ground.

This document appears to be the most comprehensive and scientifically-based set of guidelines for wolverine management. While authors Copeland and Hudak recognize the gaps in state of knowledge of wolverines, they realistically identify the need for management guidelines which translate what we already know into the best possible strategy for land managers to implement. This document, though Idaho specific, provides a template by outlining objectives, assumptions, methodologies, and guidelines which can be adapted for specific regions. Policies identified within are summarized as follows:

• Wolverine may be threatened by management’s inability to identify and address habitat concerns due to a lack of information on wolverine habitat requirements.
• Refugia provides core habitat for wolverine populations. Increased human presence, reduction, or alteration of existing refugia may threaten wolverine persistence.
• Wolverine populations may be threatened by habitat fragmentation which could lead to population isolation and eventual extinction.
• Habitat connectivity with Montana, Canadian and northern Washington most likely provides subpopulation interspersion throughout the northern range.
• Habitat alteration and human occupation within refugia may decrease subpopulation extent and interspersion as well as create barriers to emigration.
• Managers need to identify critical dispersal corridors to link subpopulations.
• Refugia must provide for basic spatial and social needs. It must also provide a natural range of floral and fauna diversity and structure.
• Mining activity, road building, or developed campgrounds near subalpine boulder talus sites may eliminate historical or potential wolverine foraging or denning habitat.
• Trapping of wolverines or incidental catches may threaten local populations.
• Predator control programs that use poison baiting techniques put wolverines at risk. Further, management practices which reduce availability of carrion availability will result in negative impacts.
• Post-partum females appear to be extremely sensitive to disturbance during the pre-weaning kit rearing period. Recreational activities may displace them from potential denning habitat or cause den abandonment.
• Low density species are difficult to monitor therefore, threats by inadequate management information on status and distribution may exist.
• The public needs to become more enlightened about the presence, life history, habitat needs, and vulnerability of this species as this may be a critical factor in the continued presence of wolverine in this region.
• Regulations for local populations must be based on regional data.
• Avoid the establishment of developed mines in core habitat.
• Avoid permanent campgrounds and establishment of road and trail systems into subalpine rock/scree sites within core habitat.

Analysis