Craig L. Gardner

Polar bear maternity denning in the Beaufort Sea

The distribution of polar bears (Ursus maritimus) is circumpolar in the Northern Hemisphere, but known locations of maternal dens are concentrated in relatively few, widely scattered locations. Denning is either uncommon or unknown within gaps between known denning concentration areas. The Beaufort Sea region of Alaska and Canada lies in the largest of those gaps. To understand effects of industrial development and proposed increases in hunting, the temporal and spatial distribution of denning in the Beaufort Sea must be known. We captured and radiocollared polar bears between 1981 and 1991 and determined that denning in the Beaufort Sea region was sufficient to account for the estimated population there. Of 90 dens, 48 were on drifting pack ice, 38 on land, and 4 on land-fast ice

Home range and habitat use by wolverines in southcentral Alaska

A wolverine (Gulo gulo) population was studied in the Susitna Basin of southcentral Alaska from 1980 to 1983. Based on logarithmic extrapolations, annual home range sizes were estimated at 535 and 105 km2 for males and postpartus females, respectively. Wolverines utilized significantly different (P < 0.05) elevational strata during different seasons (: = 1,043 and 818 m for Apr-Oct and Nov-Mar, respectively), probably in response to differences in prey distribution and abundance. Habitat analyses showed an avoidance of forest types in summer and tundra types in winter. J. WILDL. MANAGE. 50(3):460-463 The wolverine, the largest terrestrial mustelid, has a circumboreal distribution and a valuable pelt. Because wolverine population densities are naturally low and the elusive animals occupy remote habitats, few studies have been conducted. This paper describes home range, movements, and habitat use by wolverines in southcentral Alaska. This study was supported by the Alaska Power Authority and the Alaska Dep. Fish and Game (ADFG). Appreciation is expressed to ADFG employees S. R. Peterson and R. J. Tobey for reviewing early drafts of the manuscript. E. A. Goodwin provided critical lab time and support. S. M. Miller provided statistical support. K. Z. Adler handled typing and bookkeeping throughout the project. Pilots V. and C. Lofstedt, H. C. McMahan, and A. and J. Lee participated in the field aspects of the project. STUDY AREA AND METHODS The study was conducted in a 7,700-km2 portion of the upper Susitna River Basin in southcentral Alaska. Characteristics of\ the habitat have been described previously by Skoog (1968). Elevations range from 260 to 2,200 m. Low elevations are dominated by spruce (Picea spp.) forests, with a shrub and deciduous transition zone blending to tundra and shrub birch (Betula spp.) habitat types at higher elevations. From 1980 to 1983, 22 wolverines were captured, radiocollared (Ballard et al. 1982), and tracked from fixed-wing aircraft. Wolverines were subjectively aged based on tooth wear patterns and degree of maturation of reproductive organs. Radio transmitters (Telonics, Inc., Mesa, Ariz.) were enclosed in metal canisters, and the transmitter-to-antenna connection was encased in urethane. Collar webbing was made of butyl rubber with an internal stainless steel whip antenna. The entire radio-collar package weighed 430 g. Wolverine locations were gathered whenever weather and daylight permitted and were plotted on 1:63,360-scale U.S. Geological Survey topographic maps. The following data were recorded: date, time, activity, association, elevatio , aspect, slope, and associated habitat type (Viereck and Dyrness 1980). Availability of habitat to the animals was determined by recording the habitat type at each section corner of the mapped study area (McKendrick et al. 1982). Use of habitat was determined by plotting all wolverine locations that were within the mapped area (N = 178) and tallying corresponding types. Statistical comparisons between availability and use were determined by a standard F-test. Logarithmic transformations based on the relationships between the number of locations and cumulative home range size were used to project annual home range sizes. RESULTS AND DISCUSSION From April 1980 to November 1983, length of contact with instrumented wolverines ranged from 1 to 426 days (f = 147). A total of 258 point locations was gathered. Mortality (N = 10) and suspected transmitter failure (N = 7) were the primary reasons for loss of contact. In 1983, transmitters were redesigned to reduce failure. Home Range The relationship between number of locations and home range size was examined (Fig. 1) and used to estimate total annual home range

Serologic survey for canine coronavirus in wolves from Alaska

Wolves (Canis lupus) were captured in three areas of Interior Alaska (USA). Four hundred twenty-five sera were tested for evidence of exposure to canine coronavirus by means of an indirect fluorescent antibody procedure. Serum antibody prevalence averaged 70% (167/240) during the spring collection period and 25% (46/185) during the autumn collection period. Prevalence was 0% (0/42) in the autumn pup cohort (age 4–5 mo), and 60% (58/97) in the spring pup cohort (age 9–10 mo). Prevalence was lowest in the Eastern Interior study area. A statistical model indicates that prevalence increased slightly each year in all three study areas. These results indicate that transmission occurs primarily during the winter months, antibody decay is quite rapid, and reexposure during the summer is rare.

Coarse-Scale Distribution Surveys and Occurrence Probability Modeling for Wolverine in Interior Alaska

Abstract We determined wolverine (Gulo gulo) distribution and occurrence probabilities using aerial surveys and hierarchical spatial modeling in a 180,000-km2 portion of Interior Alaska, USA. During 8 February–12 March 2006, we surveyed 149 of 180 1,000-km2 sample units for wolverine tracks. We observed wolverine tracks in 99 (66.4%) sample units. Wolverine detection probability was ≥69% throughout the survey period. Posterior occurrence probabilities of whether a wolverine track occurred in a sample unit was dependent on survey timing, number of transects flown, number of neighboring sample units with detected tracks, percentage of the sample unit with elevation ≤305 m, and human influences. Our model indicated strong evidence of occurrence (>0.80) in 72% of the 180 survey units, strong evidence of absence (<0.20) in 12%, and weak evidence of occurrence or absence (0.20–0.80) in 16%. Wolverine area of occupancy made up 83% of the study area. Simulations illustrated that 2–4 survey routes were necessary for the survey technique to provide strong evidence of wolverine presence or absence in Interior Alaska if a track was not identified along the first route. The necessary number of survey routes depends on the occurrence probability in a sample unit. We provided managers with a map of wolverine distribution in Interior Alaska and an efficient and lower-cost method to detect coarse-scale changes in wolverine distribution. Our technique was effective in both Interior Alaska and Ontario, Canada, suggesting it would be effective throughout most of the boreal forest range of wolverines where tracks can be readily observed from the air. The technique requires a certain skill level in recognizing tracks; it is essential that tracks are identified correctly and training may be necessary depending on surveyor experience.

COMPARISON AND ASSESSMENT OF DRUGS USED TO IMMOBILIZE ALASKAN GRAY WOLVES (CANIS LUPUS) AND WOLVERINES (GULO GULO) FROM A HELICOPTER

One hundred and three Alaskan gray wolves and 12 wolverines were immobilized in the Nelchina and upper Susitna River Basins of southcentral Alaska between March 1977 and May 1981. Sixty five wolves were immobilized with a mixture of phencyclidine HCl and promazine HCl (PP/HCl); 38 wolves were immobilized with etorphine HCl (EHCl) and 12 wolverines were immobilized with EHCl or with a mixture of EHCl and xylazine HCl (XHCl). Phencyclidine HCl is no longer commercially available and an assessment of etorphine HCl as a replacement drug was made. Etorphine HCl dosage of 2.5 mg/wolf proved to be a suitable replacement for PP/HCl for immobilizing wolves while 0.7 mg EHCl with 50 mg XHCl appeared suitable for wolverines.

The Fortymile caribou herd: novel proposed management and relevant biology, 1992-1997

A diverse, international Fortymile Planning Team wrote a novel Fortymile caribou herd {Rangifer tarandus granti) Management Plan in 1995 (Boertje & Gardner, 1996: 56-77). The primary goal of this plan is to begin restoring the Fortymile herd to its former range; >70% of the herds former range was abandoned as herd size declined. Specific objectives call for increasing the Fortymile herd by at least 5-10% annually from 1998-2002. We describe demographics of the herd, factors limiting the herd, and condition of the herd and range during 1992-1997. These data were useful in proposing management actions for the herd and should be instrumental in future evaluations of the plans actions. The following points summarize herd biology relevant to management proposed by the Fortymile Planning Team: 1. Herd numbers remained relatively stable during 1990-1995 (about 22 000-23 000 caribou). On 21 June 1996 we counted about 900 additional caribou in the herd, probably a result of increased pregnancy rates in 1996. On 26 June 1997 we counted about 2500 additional caribou in the herd, probably a result of recruitment of the abundant 1996 calves and excellent early survival of the 1997 calves. The Team deemed that implementing management actions during a period of natural growth would be opportune. 2. Wolf (Canis lupus) and grizzly bear (Ursus arctos) predation were the most important sources of mortality, despite over a decade of the most liberal regulations in the state for harvesting of wolves and grizzly bears. Wolves were the most important predator. Wolves killed between 2000 and 3000 caribou calves annually during this study and between 1000 and 2300 older caribou; 1200-1900 calves were killed from May through September. No significant differences in annual wolf predation rates on calves or adults were observed between 1994 and early winter 1997. Reducing wolf predation was judged by the Team to be the most manageable way to help hasten or stimulate significant herd growth. To reduce wolf predation, the Team envisioned state-sponsored wolf translocations and fertility control in 15 key wolf packs during November 1997-May 2001. Also, wolf trappers were encouraged to shift their efforts to specific areas. 3. To increase social acceptance of the management plan, the Fortymile Team proposed reducing the annual caribou harvest to 150 bulls for 5 years beginning in 1996. Reducing annual harvests from 200-500 bulls (<2% of the herd, 1990-1995) to 150 bulls (<1% of the herd, 1996-2000) will not result in the desired 5-10% annual rates of herd increase. 4. We found consistent evidence for moderate to high nutritional status in the Fortymile herd when indices were compared with other Alaskan herds (Whitten et al, 1992; Valkenburg, 1997). The single evidence for malnutrition during 1992-1997 was the low pregnancy rate during 1993 following the abnormally short growing season of 1992. However, this low pregnancy rate resulted in no strong decline in Fortymile herd numbers, as occurred in the Delta and Denali herds (Boertje et al, 1996). No significant diseases were found among Fortymile caribou. 5. Winter range can support elevated caribou numbers both in regards to lichen availability on currently used winter range and the availability of vast expanses of winter range formerly used by the herd.

Short-Term Impacts of Military Overflights on Caribou During Calving Season

Abstract The Fortymile Caribou Herd (FCH) is the most prominent caribou herd in interior Alaska. A large portion of the FCH calving and summer range lies beneath heavily used Military Operations Areas (MOA) that are important for flight training. We observed the behavior of Grants cow caribou (Rangifer tarandus granti) and their calves before, during, and immediately following low-level military jet overflights. We also monitored movements of radiocollared cow caribou and survival of their calves. We conducted fieldwork from mid May through early June 2002. We concluded that military jet overflights did not cause deaths of caribou calves in the FCH during the calving period nor result in increased movements of cow–calf pairs over the 24-hour period following exposure to overflights. Short-term responses to overflights were generally mild in comparison to caribou reactions to predators or perceived predators. Caribou responses to overflights were variable, but responses were generally greater as slant distances decreased and jet speeds increased. A-10 jets caused less reaction than F-15s and F-16s. Although we found that short-term reactions of caribou to jet overflights were mild, we advise against assuming there are no long-term effects on calving caribou from jet overflights.

Movement patterns and space use of maternal grizzly bears influence cub survival in Interior Alaska

Abstract Foraging decisions and movement strategies by animals often involve a trade-off between meeting nutritional demands and minimizing risk of predation. We evaluated the influence of space use and movement patterns of maternal female grizzly bears (Ursus arctos) on cub (defined as first year of life) survival in eastern Interior Alaska, USA, during 2008–2012. We monitored 9 GPS radiocollared females that produced 28 cubs in 12 litters (x¯ litter size  =  2.3, range  =  2–3). The estimated annual cub survival rate was 0.39 (95% CI  =  0.20–0.57). In all cases the entire litter survived or died prior to den entrance. All cubs in a litter died either concurrently or within 14 days in 5 of 7 litters lost. Sixty-nine percent of cub mortality occurred between 31 May and 16 June. We did not document cub mortality before 31 May. Females with surviving cubs remained within 1 km of the den for a longer period following emergence than those that lost cubs. Between den emergence and the onset of vegetation green-up, females with surviving cubs used fewer habitat patches and remained in individual habitat patches longer than females that lost their cubs later in the summer. Females with surviving cubs exhibited different activity patterns compared with females that lost their cubs, particularly by moving less between midnight and mid-morning during 15 May–16 June. Once vegetation green-up occurred, movement rates of all maternal females were similar except that females with surviving cubs continued to move less during the morning hours (0000–1200 hr). We did not find evidence that the body size of the mother was a factor explaining cub survival nor was there evidence that cub survival was directly influenced by human causes. The most successful behavioral strategies used by maternal females to maximize cub survival appeared to be a combination of limiting movements to a few habitat patches between den emergence and vegetation green-up and limiting activity between midnight and mid-morning. We suggest that the ability to find and exploit suitable habitat patches during this period of limited resources may have allowed females to alter movements temporally and spatially and provision themselves and their cubs more effectively. This strategy was likely effective for both minimizing exposure to infanticidal adult bears and allowing cubs to maximize energy efficiency.

Rebuilding the Fortymile caribou herd: A model of cooperative management planning

We examined the public process used to develop the 1996—2001 Fortymile Caribou (Rangifer tarandus) Herd Management Plan adopted by state and federal management boards. The process differed from most government-supported planning processes because it was initiated by residents of Alaska and Yukon, and not by an agency. State, federal, and territorial agencies were asked to participate in and support development of a management plan that would include a broad range of interest groups. We describe the planning effort, issues addressed by the planning team that posed significant challenges during both the planning and implementation phases, and then identify unforeseen costs and benefits derived from the process. Critical decision points in plan development and implementation are discussed.