David K. Person

A Signal for Independent Coastal and Continental histories among North American wolves

Relatively little genetic variation has been uncovered in surveys across North American wolf populations. Pacific Northwest coastal wolves, in particular, have never been analysed. With an emphasis on coastal Alaska wolf populations, variation at 11 microsatellite loci was assessed. Coastal wolf populations were distinctive from continental wolves and high levels of diversity were found within this isolated and relatively small geographical region. Significant genetic structure within southeast Alaska relative to other populations in the Pacific Northwest, and lack of significant correlation between genetic and geographical distances suggest that differentiation of southeast Alaska wolves may be caused by barriers to gene flow, rather than isolation by distance. Morphological research also suggests that coastal wolves differ from continental populations. A series of studies of other mammals in the region also has uncovered distinctive evolutionary histories and high levels of endemism along the Pacific coast. Divergence of these coastal wolves is consistent with the unique phylogeographical history of the biota of this region and re‐emphasizes the need for continued exploration of this biota to lay a framework for thoughtful management of southeast Alaska.

Correlates of Mortality in an Exploited Wolf Population

Abstract We investigated the influence of habitat use on risk of death from hunting and trapping of 55 radiocollared gray wolves (Canis lupus) from an exploited insular population in Southeast Alaska, USA. We compared mortality rates for resident and nonresident wolves and used Cox proportional hazards regression to relate habitat composition within 100-m circular buffers around radiolocations to risk of death of resident and nonresident wolves. In addition, we included covariates representing distances to roads, logged stands, and lakes and streams in those analyses. We also compiled harvest data from 31 harvest units within the study area to compare densities of roads and distances from human settlements with rates of harvest. During our study 39 wolves died, of which 18 were harvested legally, 16 were killed illegally, and 5 died from natural causes. Legal and illegal harvest accounted for >87% of the mortality of radiocollared resident and nonresident wolves. Mean annual survival was 0.54 (SE = 0.17) for all wolves. Annual survival was 0.65 (SE = 0.17) for resident wolves and 0.34 (SE = 0.17) for nonresidents. Very few (19%) nonresident wolves survived to colonize vacant territories or join existing wolf packs. Roads, muskegs, and distances from lakes and streams were covariates positively associated with death of resident wolves. Clear-cuts were positively associated with risk of death of nonresident wolves. Rate of harvest increased with density of roads; however, road densities >0.9 km/km2 had little additional effect on harvest rates. Harvest rates decreased with ocean distances from nearest towns or settlements. Roads clearly increased risk of death for wolves from hunting and trapping and contributed to unsustainable rates of harvest. Wildlife managers should consider effects of roads and other habitat features on harvest of wolves when developing harvest recommendations. They should expect substantial illegal harvest where wolf habitat is accessible to humans. Moreover, high rates of mortality of nonresident wolves exposed to legal and illegal harvest may reduce or delay successful dispersal, potentially affecting linkages between small disjunct wolf populations or population segments. We conclude that a combination of conservative harvest regulations and large roadless reserves likely are the most effective measures for conserving wolves where risks from human-caused mortality are high.

Risk Factors and Mortality of Black-Tailed Deer in a Managed Forest Landscape

Abstract We investigated the influence of habitat use on the risk of death of Sitka black-tailed deer (Odocoileus hemionus sitkensis) on Heceta Island in Southeast Alaska, USA. A mosaic of even and uneven-aged forests covered much of the island and provided a model setting in which to assess relationships between habitat use and mortality of deer. We radiocollared and monitored 51 adult females, 11 adult males, and 19 young of the year. We compared risk of death with habitat composition, habitat distribution, topography, distances to features such as roads, and functional habitat characteristics such as seasonal forage biomass within 50-, 500-, and 1,000-m circular buffers around relocations of deer. Those buffers encompassed habitats used at scales of radio-locations, home ranges, and landscapes. We addressed hypotheses that related habitat composition and distribution to risk of death from malnutrition, predation, and hunting. Predation by wolves (Canis lupus) and malnutrition were the principal causes of death of adult females and young, whereas hunters killed most adult males. Habitat factors at scales of 500 and 1,000 m had the greatest effect on mortality of adult females and young, whereas habitat characteristics in the immediate vicinity of radio relocations had the greatest effect on mortality of adult males. Malnutrition was positively associated with use of forage-poor habitats such as pole-stage, second-growth forest. Use of precommercially thinned second growth increased risk of death for young deer. Use of level terrain was the most influential factor with respect to predation and increased risk of death at all scales. Use of open habitats, such as muskegs and young clearcuts, also increased risk of death. Use of shrub-sapling-stage clearcuts in landscapes accessible by roads increased risk of death from hunting. We showed that use of specific habitats and the landscape context of those habitats were important factors influencing mortality of deer. We also demonstrated the importance of comparing habitat use with measures of fitness rather than simply with availability when evaluating habitat suitability for deer. Our results should be useful to wildlife researchers investigating contributions of habitat to fitness and population dynamics of ungulates, and to wildlife managers attempting to manipulate habitats to benefit deer populations.

Estimating Abundance of Sitka Black-Tailed Deer Using DNA From Fecal Pellets

ABSTRACT Densely vegetated environments have hindered collection of basic population parameters on forest-dwelling ungulates. Our objective was to develop a mark—recapture technique that used DNA from fecal pellets to overcome constraints associated with estimating abundance of ungulates in landscapes where direct observation is difficult. We tested our technique on Sitka black-tailed deer (Odocoileus hemionus sitkensis) in the temperate coastal rainforest of Southeast Alaska. During 2006–2008, we sampled fecal pellets of deer along trail transects in 3 intensively logged watersheds on Prince of Wales Island, Alaska. We extracted DNA from the surface of fecal pellets and used microsatellite markers to identify individual deer. With genotypes of individual deer, we estimated abundance of deer with moderate precision (±20%) using mark—recapture models. Combining all study sites, we identified a 30% (SE = 5.1%) decline in abundance during our 3-year study, which we attributed to 3 consecutive severe winters. We determined that deer densities in managed land logged >30 years ago (7 deer/km2, SE = 1.3) supported fewer deer compared to both managed land logged <30 years ago (10 deer/km2, SE = 1.5) and unmanaged land (12 deer/km2, SE = 1.4). Our study provides the first estimates of abundance (based on individually identified deer) for Sitka black-tailed deer and the first estimates of abundance of an unenclosed ungulate population using DNA from fecal pellets. Our tool enables managers to accurately and precisely estimate the abundance of deer in densely vegetated habitats using a non-invasive approach.

Reproduction and Den Site Selection by Wolves in a Disturbed Landscape

Abstract We studied litter sizes, den characteristics, and den site selection by wolves (Canis lupus ligoni) on Prince of Wales and adjacent islands in Southeast Alaska, USA. The study area was extensively logged and roaded enabling us to examine effects of those factors on den site selection. We counted pups in dens during May using an infrared video camera with a flexible-shaft. We recorded habitat features at dens and used logistic regression to compare den site characteristics within 100-m and 1000-m circular buffers around dens with randomly matched unused locations. Litter size averaged 4.1 (SD = 1.7) pups, however, average litter sizes of six first-time breeding females were smaller ( = 3.0, SD = 2.5). Dens were located in root wads of large living or dead trees within old-growth forest stands <150m from freshwater. Within 100-m and 1000-m buffers, wolves selected coarse-canopy old-growth forest stands and muskegs adjacent to lakes, ponds or streams, on gentle slopes, that were farther from logged stands and roads than unused locations. Landscape features such as elevation and slope, and proximity of fresh water had the greatest effects on den site selection. Covariates tabulated within 100-m buffers had much greater influence on den site selection than variables tabulated within 1000-m buffers indicating that wolves mostly responded to features within the immediate vicinity of dens. Wolves generally avoided clearcuts and roads but they tolerated intense disturbances of short duration during our den visits. We suggest wolves prefer locations away from roads and clearcuts but will select them if suitable alternative locations do not exist. Once established at den sites, wolves will tolerate some human disturbance at least of short duration.

Individual identification of Sitka black-tailed deer (Odocoileus hemionus sitkensis) using DNA from fecal pellets

We tested a protocol for extracting DNA from fecal pellets from Sitka black-tailed deer (Odocoileus hemionus sitkensis) and evaluated genotyping performance of previously developed microsatellite markers as well as a suite of new markers designed specifically for this study. We screened 30 microsatellites, and identified 7 (23%) loci including 4 new markers, that fit well into a single multiplex and consistently genotyped deer with low error rates. DNA was extracted from 2,408 fecal-pellet samples. Of those, 1,240 (52%) were genotyped successfully at all 7 markers allowing identification of 634 genetically unique deer. Using DNA from fecal pellets collected in the field was an effective technique for identifying and distinguishing among deer.

Sex and scale: implications for habitat selection by Alaskan moose Alces alces gigas

Abstract We examined the roles of sex and spatial scale in habitat selection by Alaskan moose Alces alces gigas. We GPS-collared 11 female and seven male adult moose in the Tongass National Forest, Alaska, USA, during 2002-2004. We predicted that adult male and female moose would be spatially separated outside of the mating season, consistent with hypotheses attributing sexual segregation among sexually dimorphic ruminants to allometric differences in body and gastrointestinal size, and resulting differential needs for nutrient requirements by the sexes (the gastrocentric hypothesis), and varying risks of predation (the predation hypothesis) between sexes, especially for females with young. We predicted that habitat selection would be similar between sexes during the mating season, but dissimilar and occur at different scales during periods of late gestation and lactation. We expected that during segregation, females would select for a higher percentage of forested cover and a higher edge density than males to reduce predation risk on their young. Furthermore, we examined whether differences in scale of habitat selected between the sexes was related to home-range size. Multi-response Permutation Procedures (MRPP) analysis indicated that the spatial distributions of adult males and females differed, particularly near or during parturition. The sexes selected habitats similarly during the mating season (rut), when sexes generally were aggregated, whereas sexes exhibited differential habitat selection during spring, when sexes were segregated. Habitat selection by both sexes was best explained by vegetation and landscape composition tabulated within 1,000-m radii centered on GPS locations of moose. The sexes did not differ in the scale at which they selected habitats. Mean size of the annual home range was 76 km2 for females and 125 km2 for males, but size of home range was not related to scale of habitat selection by moose. Our results indicate that females were likely selecting habitat with high-quality forage while minimizing predation risk during periods of sexual segregation, whereas males were selecting habitat that allowed high forage intake, which together provide support for both the gastrocentric and the predation hypotheses.

Linking Hunter Knowledge with Forest Change to Understand Changing Deer Harvest Opportunities in Intensively Logged Landscapes

The effects of landscape changes caused by intensive logging on the availability of wild game are important when the harvest of wild game is a critical cultural practice, food source, and recreational activity. We assessed the influence of extensive industrial logging on the availability of wild game by drawing on local knowledge and ecological science to evaluate the relationship between forest change and opportunities to harvest Sitka black-tailed deer (Odocoileus hemionus sitkensis) on Prince of Wales Island, Alaska. We used data collected through interviews with local deer hunters and GIS analysis of land cover to determine relationships among landscape change, hunter access, and habitat for deer hunting over the last 50 yr. We then used these relationships to predict how harvest opportunities may change in the future. Intensive logging from 1950 into the 1990s provided better access to deer and habitat that facilitated deer hunting. However, successional changes in intensively logged forests in combination with a decline in current logging activity have reduced access to deer and increased undesirable habitat for deer hunting. In this new landscape, harvest opportunities in previously logged landscapes have declined, and hunters identify second-growth forest as one of the least popular habitats for hunting. Given the current state of the logging industry in Alaska, it is unlikely that the logging of the remaining old-growth forests or intensive management of second-growth forests will cause hunter opportunities to rebound to historic levels. Instead, hunter opportunities may continue to decline for at least another human generation, even if the long-term impacts of logging activity and deer harvest on deer numbers are minimal. Adapting hunting strategies to focus on naturally open habitats such as alpine and muskeg that are less influenced by external market forces may require considerably more hunting effort but provide the best option for sustaining deer hunting as a local tradition over the long run. We speculate that managing deer habitat in accessible areas may be more important than managing the overall health of deer populations on a regional scale. We further suggest that the level of access to preferred hunting habitat may be just as important as deer densities in determining hunter efficiency.

Metrics of predation: perils of predator-prey ratios

We developed an original modeling approach using program Stella® to investigate the usefulness of predator–prey ratios (PPRs) for interpreting top-down and bottom-up forcing on moose Alces alces. We included density-dependent feedbacks for the moose population, allowed K to vary based on amount and quality of available forage for moose, integrated effects of compensatory mortality, and added time lags in wolves Canis lupus tracking the moose population. Modeling scenarios we developed included bottom-up and top-down regulation as predetermined outcomes. We then evaluated whether PPRs would reflect the various combinations of trajectories of predator and prey populations under top-down versus bottom-up regulation. The resulting patterns of PPRs were impossible to disentangle from one another, and did not provide reliable insights into whether top-down or bottom-forcing occurred, especially over short time spans where critical decisions related to management of moose and wolves might be necessary. Only under top-down regulation did PPRs reflect the degree of predation experienced by moose, but in that instance, knowledge of top-down regulation must be known a priori to correctly interpret PPRs. Potential problems with interpreting PPRs include their double-variable nature, which resulted in the failure to reflect patterns of increase and decrease for predators and prey. We suggest that confidence intervals for PPRs be calculated from a binomial, similar to that proposed for sex and age ratios, which should help discourage the inappropriate use of this metric. We caution that the temptation to use PPRs often is irresistible, but their reliability is highly questionable. We provide an alternative method to using PPRs or other predation metrics for determining whether top-down or bottom-up forcing is occurring by adopting an approach based on the physical condition and life-history characteristics of prey.