Conservation and Ecology of Mammals – Carnivores

Contributed Paper
ROOM: Rooms 27 – Picuris, 29 – Sandia and 31 – Santa Ana Combined
SESSION NUMBER: 78
 

1:10PM Preliminary Predation Patterns of Cougars and Wolves in an Area of Sympatry
Elizabeth K. Orning; Katie M. Dugger; Darren A. Clark
ABSTRACT Expanding gray wolf (Canis lupus) populations and interspecific competition with sympatric cougars (Puma concolor) presents new challenges for management of multiple carnivore effects on ungulate populations (e.g., elk, Cervus elephus; mule deer, Odocoileus hemionus) in the western United States. We examined wolf and cougar predation patterns before (2009-2012) and after (2014-2016) wolves recolonized the Mt. Emily Wildlife Management Unit in northeast Oregon. We identified 1,213 and 541 prey items utilized by cougars in the pre- and post-wolf periods, respectively. We also identified 158 prey items utilized by wolves. Cougar diet was similar between the pre- and post-wolf time periods. Cougar preyed predominantly on deer (mule deer and white-tailed deer, O. virginianus; 58% and 53% of all ungulate kills pre- and post-wolf, respectively) and primarily killed fawns (53% and 44% of all deer kills, pre- and post-wolf, respectively). When cougar preyed on elk, they primarily preyed on calves pre – (77%) and post-wolf (71%) recolonization. Wolves preyed predominantly on elk (61%) and primarily killed the calf age class of elk in summer (83%) and winter (49%), but used adult elk nearly as often as calves in winter (46%). Strong selective predation on elk calves coupled with high density cougar populations explained the low recruitment and reduced population growth rates of elk in Oregon before wolves recolonized the state. The continued selection of elk calves by cougars coupled with wolf predation may intensify the effects of carnivores on elk populations. Conversely, wolves may ultimately decrease cougar densities such that effects on elk populations remain relatively unchanged in this multi-predator system. As wolf populations continue to expand, additional research is needed to clarify the combined effect of wolves and cougars on elk population dynamics. KEY WORDS cougar, wolf, elk, mule deer, competition, prey selection, predation, ungulate mortality, Oregon.
1:30PM Variable Effects of Harvest within and Across Wolf Packs in the Rocky Mountains
Sarah B. Bassing; Dave E. Ausband; Mike S. Mitchell; Paul M. Lukacs; Mike K. Schwartz; Greg Hale; Lisette P. Waits
Pubic harvest is a common method used to manage populations of wolves (Canis lupus) but individual- to population-level responses to harvest may differ. Wildlife agencies want to understand this variation to effectively meet management objectives when using harvest to manage populations of wolves. Because wolf packs are the reproductive unit in a population, we were interested in how wolf populations responded to harvest within and among packs across the Rocky Mountains. We hypothesized the occurrence of packs would change frequently and populations were maintained by immigrants replacing individuals and packs lost to harvest. We used noninvasive genetic data collected in central Idaho (2008 – 2014) and southwestern Alberta (2012 – 2014) to identify potential immigrants and assess the response of immigration to harvest. We also used occupancy models to estimate the abundance and distribution of packs and assess the frequency of pack turnover in a population that was heavily harvested. We identified 461 unique individuals with genetic analyses across our study areas. We found little evidence of whole-pack turnover, despite heavy harvest. Immigration did not compensate for harvest mortality in either population, but packs appeared receptive to adopting local dispersers depending on breeding opportunities within packs. In addition, packs were on average smaller and pup recruitment lower compared to unharvested populations. Although immigration and reproduction did not appear to compensate for harvest mortality, pack occurrence remained generally stable over time due to movement between packs from within the population. Harvest therefore appears to affect within-pack dynamics, but may not directly affect the number and distribution of packs across a population. Factors other than harvest, such as habitat quality or prey density, likely determine the occurrence of packs.
1:50PM Assessing Translocation Strategies for Swift Fox in the Northern Great Plains
Donelle Schwalm; Kristy Bly
Re-establishing species when they are extirpated by human activity is a common goal in wildlife conservation. One method for achieving this goal is translocation, where individuals are moved from existing populations to suitable, unoccupied habitat. The monetary, logistic and ethical considerations of translocation provide impetus for careful planning to ensure biologically and ecologically meaningful results. Swift fox (Vulpes velox), a species of conservation concern, were extirpated from >50% of their historic range in the Great Plains as a result of predator control programs and altered land cover/land use patterns. Multiple translocation programs have attempted to reintroduce swift foxes in the Northern Great Plains (NGP), where the species is still largely absent. Program success varied, resulting in spatially isolated populations not connected to the core of the remnant population located in the Central Great Plains. Considerable interest by stakeholders in the NGP exists for additional translocation projects to connect populations. We identified two primary goals for swift fox translocation in the NGP: establishing populations with long-term viability and generating linkage between existing isolated populations and the core of the species distribution. We used a Habitat Suitability Index developed with occupancy data from swift fox in the NGP to identify potential release sites, based on habitat quality and the number of home ranges they could support. Using HexSim, a spatially explicit, individual based modelling framework, we tested the influence of order in which individual release sites receive swift fox, number of foxes released each year, and number of years foxes are released. We used the results of these tests to identify the most efficacious approach for reaching the pre-defined goals of population viability and connectivity. The results of these simulations were used to develop a restoration strategy for swift fox in the NGP.
2:10PM Wolf Recolonization Threatens Caribou Persistence on Michipicoten Island, Ontario
Brent R. Patterson; Arthur R. Rodgers; Jen Shuter; Carol Dersch; Steve Kingston; Evan McCaul
Predation has the potential to shape the structure and function of entire ecosystems. Nonetheless, debate persists regarding whether the abundance of various ungulate populations is regulated by top down or bottom up forces. Woodland caribou (Rangifer tarandus caribou) are a threatened species, both federally in Canada and provincially in Ontario. Much has been written about the role of anthropogenic landscape disturbance in exacerbating wolf (Canis lupus) predation on caribou, in some cases leading to serious conservation concern. However, despite their declining status on most mainland areas, caribou have remained abundant on some predator-free coastal islands in Lake Superior, Ontario. One such place is the relatively undisturbed 188 km2 Michipicoten Island, which was naturally recolonized by 4 wolves via an ice bridge in winter 2014. Our objective was to determine the impact of wolf predation on caribou in this system where wolves are the only substantive predator of caribou but also prey on an abundant beaver (Castor canadensis) population. Specifically, we are testing the hypothesis that where wolves are present, predation rather than food abundance is the primary factor limiting caribou abundance. We estimated caribou numbers via a combination of aerial quadrat surveys and camera trapping, and estimated that there were approximately 450 caribou present on the island in autumn 2014, 6-8 months after wolf recolonization. By winter 2017 wolf numbers had at least tripled and caribou abundance had declined by ≥ 60 %. We expect wolves to remain abundant as caribou continue to decline because beaver remain abundant and represent a substantive alternate prey source. Population models suggest that extirpation of caribou as soon as 2020 is possible. Although preliminary, these data support Bergerud’s 1974 contention that predation rather than a shortage of winter lichens may be the primary factor limiting abundance of woodland caribou.
2:30PM Resource Selection by Coastal Wolves Reveals the Seasonal Importance of Seral Forest and Suitable Prey Habitat
Gretchen H. Roffler; David P. Gregovich; Kristian R. Larson
Wolves (Canis lupus) in Southeast Alaska inhabit temperate rainforests characterized by a patchwork of structured old-growth and harvested forest stands in various stages of regeneration. Investigating wolf space-use patterns in this landscape may yield information on their tolerance of anthropogenic disturbance in forest ecosystems. Furthermore, identifying shifts in habitat selection throughout the year can provide insights into wolves’ ability to exploit seasonally available resources. Our objectives were to examine seasonal habitat selection of wolves on Prince of Wales Island, Alaska with respect to forest structure, succession, land cover, topography, road densities and habitat predicted to support Sitka blacked-tailed deer (Odocoileus hemionus sitkensis) and salmon (Onchorynchus spp.), the primary and a secondary prey species, respectively. We used locations from 13 GPS-collared wolves during 2012-2016 to develop resource selection functions (RSFs) and estimate seasonal home range size. Within their home ranges, wolves selected low elevation, flat terrain with open land cover and low-volume old-growth forests across seasons. During fall and winter wolves preferred clearcuts ≤30 years old, but avoided clearcuts > 30 years old and thinned young-growth. Habitats with predicted high deer carrying capacities were selected during late summer and fall, and areas close to anadromous streams were important only during summer when salmon were spawning. Areas of high road densities were avoided during denning season and summer, but strongly selected during winter. Results of this study were integrated into spatially-explicit capture-recapture models to estimate wolf density and used to inform landscape-level forest management recommendations for wolf habitat. This work reveals the potential of wolves to seasonally target prey and adjust to altered landscapes, but successional forests had a limited period of use (<30 years), thus forest transition could influence wolves’ long-term viability.
2:50PM Refreshment Break
3:20PM Estimating Recruitment of Wolves with Limited Data
Allison C. Keever; Michael S. Mitchell; Kevin M. Podruzny; Angela D. Luis; James T. Peterson
Successfully managing a species can require information on basic demographics. Recruitment is particularly important for harvested species because it determines the level of harvest that can be sustained by the population; thus, this information can be used to improve harvest decisions. When management occurs across large spatial scales, however, these data can be costly or highly difficult to collect and are often unavailable at the scale needed to inform management decisions. Management of gray wolves (Canis lupus) in Montana could benefit from information about the spatial and temporal variation in recruitment. Existing data are insufficient for traditional methods to estimate recruitment of wolves, therefore a new approach is needed. Our objectives were to develop a method to estimate and determine the factors that explain the spatial and temporal variation in wolf recruitment using available data. Integrated population models can be a useful tool for demographic analyses from limited data sets. We developed an integrated population model to use collar, hunter survey, and group count data to estimate recruitment of wolves. These data were available from ongoing monitoring, and this method did not require collecting any additional data. We first tested the model on a simulated data set to determine model sensitivity to the amount of data used. Then we evaluated the spatial and temporal variation in wolf recruitment rate. We found that the model estimated the true parameter values from the simulated data accurately with 10 years of data from 40 group counts and 120 sites with 10 survey occasions per site for occupancy. Accuracy of estimates declined with decreasing amounts of data used for analysis. Recruitment in wolves varied by region across the state and varied temporally. This method can help reduce costs associated with monitoring wolf populations while providing valuable information needed to help inform management decisions.
3:40PM Using Genetic Pedigree Reconstruction to Support Recovery of the Wild Mexican Gray Wolf Population
Jennifer R. Adams; Colby Gardner; Dyan Straughan; Maggie Dwire; Sherry Barrett; Lisette P. Waits
Maintaining the genetic diversity and health of small, reintroduced populations is an important consideration for endangered species programs. Pedigrees are a useful way to monitor effective population size and genetic diversity in a population but can be difficult to maintain in wild populations of wide ranging species. Genetic pedigree reconstruction can ameliorate the difficulties associated with determining accurate pedigrees for wild populations. The Mexican gray wolf (Canis lupus baileyi) reintroduced to the wild since 1998 and ranging over 13,329 square miles is a population that could benefit from genetic pedigree reconstruction. Mexican gray wolves, trace their ancestry to seven individuals who founded the captive breeding colony, which makes genetic pedigree reconstruction more challenging due to the higher degree of relatedness between individuals. Multi-locus microsatellite genotypes at 22 loci were generated for 95% of the individuals captured in the wild. Mexican gray wolf origin was genetically confirmed for each individual using a Bayesian clustering method (STRUCTURE) and a reference database of Mexican gray wolves, Rocky Mountain gray wolves, coyotes and dogs. Individuals confirmed to be Mexican gray wolves were then separated into year of birth cohorts based upon estimated age at capture and were tested against all individuals of breeding age at the time of each breeding season. Pedigree assignments were made based upon the results from program CERVUS and corroborating field data. A total of 227 pedigree assignments were confirmed or established. For an additional 16 individuals one parent was confirmed based upon zero or one genotype mismatch with the putative offspring. All sampled individuals could be completely (both parents) or partially (1 parent) assigned to the pedigree. Reconstruction of the wild pedigree has allowed the Mexican gray wolf recovery program to better manage the reintroduced population to maintain genetic diversity.
4:00PM Large Carnivore Reintroductions Outside of Protected Areas and the Need for Ongoing Conservation Management.
Jay V. Gedir; James W. Cain III; John K. Oakleaf; Stewart W. Breck
Large carnivore reintroductions are challenging because of conflicts with humans, they are often established from few founders and because of their impacts on other species in their role as apex predators. These factors can lead to low demographic rates in the wild, requiring ongoing conservation management for population sustainability. We used survival and pup recruitment rates from the Mexican wolf (Canis lupus baileyi) reintroduction in the southwestern United States (1998-2014) in individual-based population models to determine optimal release and management strategies for achieving population growth. Despite higher survival in released wild-born wolves (i.e., captured wolves that spent time in captivity before release), it was not enough for population growth. This was largely due to high rates of nuisance or depredation behaviour by wolves, which were managed through translocations and removals prior to 2009, and were treated as mortalities in survival analyses. When problem wolf management shifted from removals to diversionary feeding to deter wolves from livestock depredation, populations grew, even after wolf releases ceased. Overall pup recruitment was low (1.76 pups/pack), and recruitment augmentation simulations demonstrated that subtle increases could change population growth rates from negative to positive. Findings indicate that management of reintroduced large carnivores to reduce depredation and nuisance scenarios is unavoidable, and improving demographic rates involves tradeoffs between management actions aimed at reducing conflict with humans and maintaining population genetic diversity. This study advances our understanding of the exigencies of large carnivore reintroductions and provides insight into beneficial strategies that could aid other species reintroductions.
4:20PM Harvest and Group Effects on Pup Survival in Gray Wolves
David Ausband; Mike Mitchell; Carisa Stansbury; Jennifer Stenglein; Lisette Waits
Recruitment in cooperative breeders can be negatively affected by reductions in group size, changes to group composition and breeder turnover. We wanted to know how human harvest affects group size, composition, and ultimately pup survival in gray wolves (Canis lupus). We used noninvasive genetic sampling and 18 microsatellite loci to construct group pedigrees and estimate pup survival for wolves under 3 different harvest regimes ranging from heavily harvested to fully protected in Alberta, Canada, and Idaho and Yellowstone National Park (YNP), USA. We hypothesized that harvest reduces pup survival because of 1) reduced group size, 2) increased breeder turnover and/or 3) reduced number of female helpers. Alternatively, harvest may increase pup survival possibly due to increased per capita food availability or it could be compensatory with other forms of mortality. Harvest appeared to be additive because it reduced both pup survival and group size. In addition to harvest, turnover of breeding males and the presence of older, nonbreeding males also reduced pup survival. Large groups and breeder stability increased pup survival when there was harvest, however. Inferences about the effect of harvest on recruitment requires knowledge of harvest rate of young as well as the indirect effects associated with changes in group size and composition as we show. The number of young harvested is a poor measure of the effect of harvest on recruitment in cooperative breeders.
4:40PM Trophic Ecology and Activity Patterns of Mountain Lion and Culpeo Fox in Chilean Central Andes
Christian T. Osorio Popiolek; Ana S. Muñoz; Nicolás Guarda; Marcella Kelly; Cristian Bonacic
Mountain lions (Puma concolor) and Culpeo foxes (Lycalopex culpaeus) coexist in the Andes of central Chile. Coexistence between sympatric carnivores is subject to ecological constraints of direct and indirect interspecific competition. Thus, current niche similarity between these two species makes it difficult to explain their coexistence given the subordinate competitor (the culpeo fox) must shift in niche dimension to reduce niche overlap. Most research on carnivores, especially pumas, in Chile has been conducted in the southernmost areas and there is a notable lack of information about such species in central Chile. Furthermore, the interactions between carnivores have not been studied in the Andean region of southern South America. We estimated temporal activity pattern overlap from camera trap surveys and trophic niche overlap from scat (i.e. diet) analysis to assess mechanisms underlying coexistence of the two main carnivores in the Andean Mediterranean Region of central Chile. For temporal overlap, we used non-parametric kernel density overlap metrics between carnivores and for trophic niche overlap we used the Simplified Morisita Index. Additionally, we used temporal overlap metrics between carnivores and exotic species (i.e.: hares (Lepus europaeus) and rabbits (Oryctolagus cuniculus)) to determine whether such prey play a role in shaping activity patterns and potential trophic relationships. Based on the high activity pattern overlap and low trophic niche overlap, we found that mountain lions and culpeo foxes segregate primarily along the trophic axis of their ecological niche in order to coexist. Data also suggests fine scale spatial avoidance of pumas by foxes. We also found high temporal overlap between predators and prey and that introduced hares have become important prey for the puma in the area. Further research is needed regarding potential impacts of control and/or eradication of this species. We provide the first study baseline information on carnivore community ecology in central Chile.

 

Contributed Paper
Location: Albuquerque Convention Center Date: September 26, 2017 Time: 1:10 pm - 5:00 pm