Conservation and Ecology of Mammals – Carnivores

Contributed Paper
ROOM: Rooms 16 – Acoma, 32 – Teseque and 15 – Zuni Combined
SESSION NUMBER: 50
 

1:10PM A Novel Approach to Estimation of American Badger Density Using Spatially Explicit Capture-Recapture Models and Automatic Cameras at Water Sources in the Chihuahuan Desert
Robert Harrison; Matthew Gould
American badgers (Taxidea taxus) are relatively large members of the weasel family Mustelidae. They occur in the United States from the Pacific coast to Texas and Ohio, in Canada from British Columbia to Ontario, and in Mexico from the United States border to Jalisco and Guanajuato. Most studies of badgers have occurred in California and the northern portions of their range while few have occurred in southern habitats. Badger density was estimated in Utah and Idaho and Wyoming, but we have no measurements of badger density in desert habitats. Badger density is expected to be low in desert habitats, rendering trapping especially inefficient. To measure badger density in a desert habitat, we placed automatic cameras at water drinkers in the Chihuahuan Desert, identified individual badgers by their dorsal pelage, and estimated badger density using an SECR analysis. We used a suite of covariates to explain heterogeneity in the detection process and to investigate variation in badger density relative to their life history. The estimated density from the top model in our analysis was 15.19 badgers/100 km2 (95% CI: 10.20 – 22.63). This is the first study to utilize noninvasive identification of individual badgers through photographs, and the first to use location data at drinkers to estimate badger density in a desert ecosystem.
1:30PM Occupancy Dynamics of River Otter as a Function of Stream And Riparian Communities
Angela Holland; Eric Hellgren; Clayton Nielsen; Eric Schauber
River otter (Lontra canadensis) play critical roles in freshwater aquatic systems as trophic-transfer agents and apex predators. Reintroduction of river otter to Illinois in 1994-1996 provided the opportunity to assess relationships between these recovering predators and stream and riparian communities. We used multi-season occupancy modeling to identify aspects of the stream and riparian communities, including prey diversity, stream quality, and interactions with other semi-aquatic mammals (beaver [Castor canadensis], mink [Neovison vison], and muskrat [Ondatra zibethicus]), that explain occupancy dynamics of river otter. We surveyed for semi-aquatic mammals at 77 bridge sites in Jan-Feb and Mar-Apr 2012-2014 in 11 major watersheds in southern Illinois (44,526 km2). Each survey unit was a 400-m stream segment visited twice by 2 observers. Stream quality and prey diversity data were collected before 2012 by the state of Illinois. Occupancy during the initial survey period was higher in sites closer to the reintroduction points for river otter (β = -0.016, SE = 0.007). Probability of colonization of river otter was positively associated with macroinvertebrate IBI (β = 0.034, SE = 0.013) and fish species richness (β = 0.058, SE = 0.031). Sites with high fish species richness of species belonging to the families Centrarchidae, Catostomidae, Cyprinidae, and Ictaluridae had decreased probability of extinction of river otter (β = -0.075, SE = 0.042). Increased species richness is positively linked to habitat heterogeneity and may indicate increased system stability. Thus, our results suggest that habitat heterogeneity and system stability are important to river otter site use.
1:50PM Too Close for Comfort? Inbreeding Dynamics in a Small Mountain Lion Population Is Greater Los Angeles
John F. Benson; Jeff A. Sikich; Devaughn L. Fraser; Robert K. Wayne; Holly B. Ernest; Seth P.D. Riley
Inbreeding occurs in small wildlife populations and can have negative consequences for population viability if individual fitness is compromised due to low genetic diversity. We documented family relationships for 56 mountains lions (Puma concolor) in a small (<20), isolated population of mountain lions in greater Los Angeles, California. Previous research has indicated that this population (along with another in southern California) exhibited the lowest genetic diversity documented for western mountain lions, that intraspecific strife is the most common source of mortality, and that rapid erosion of genetic diversity through inbreeding could greatly increase probability of extinction. Here, we provide additional insight on inbreeding dynamics and behaviors influencing fitness in this small population by conducting a detailed pedigree analysis using genetic and telemetry data collected from 2002-2017. Specifically, we investigated 1) the nature and frequency of breeding between close relatives, 2) the degree of male reproductive skew, and 3) whether intraspecific mortality included killing of close relatives. Additionally, our pedigree provided insight into dispersal patterns within this highly fragmented landscape. We documented 5 mating events between fathers and daughters and 1 between siblings. Male reproductive skew was high as only 2 males were documented breeding during the first 13 years of the study. One of these males mated with a female that was both his daughter and granddaughter, highlighting the extreme nature of inbreeding in this population. Male mountain lions killed their own offspring, their siblings, as well as females they had previously mated with. Thus, we documented mating and other behaviors that are rare or unique in the scientific literature, and are counter-intuitive from the perspective of evolutionary fitness. These findings appear to be driven by the extremely constrained nature of this isolated population and contribute broadly to theoretical and practical understanding of the biology of small wildlife populations.
2:10PM Resting Microsite Use by Fishers and Boreal Martens: Role of Thermal Stress Across Species and Regions
Michael J. Joyce; Andrzej Zalewski; John D. Erb; Ron A. Moen
Species in the Martes Complex (fishers [Pekania pennanti], martens [genus Martes], and wolverines [Gulo gulo]) occupy broad geographic ranges with significant regional variation in climate regime, forest type and age, and plant and animal community structure. Eight of 11 species in the Martes Complex live in northern forest ecosystems, where during winter they must cope with nutritional limitation, extreme environmental conditions, and physiological constraints imposed by body morphology. Our objective was to evaluate the role of thermal stress on resting habitat use across species in the Martes Complex. We reviewed literature on resting microsite use by martens and fishers and performed a retrospective meta-analysis to examine the effect of thermal stress on microsite use at 3 different levels: (1) seasonal differences in microsite use within species; (2) geographic variation in microsite use within species; and (3) geographic variation in microsite use among species. We predicted fishers and martens would use ground microsites (e.g., hollows in logs, burrows, etc.) more frequently during winter and in areas with severe winter conditions because ground microsites provide thermal protection when insulated by snow. Fishers and martens rested more frequently in ground microsites during winter compared to non-winter seasons, although there was significant variation among studies. Ground microsites were used more frequently by fishers and martens in areas with severe winter climates than in areas with milder winter conditions. Because martens are smaller than fishers, have a higher surface-area-to-volume ratio, and have shorter and less insulative fur, they are more vulnerable to thermal stress during the winter. Consequently, martens used thermally-protective ground microsites more frequently than fishers. Our results suggest that resting habitat is an important component of behavioral thermoregulatory strategies for both fishers and martens.
2:30PM Quantifying Rest Structure Reuse Rates by Pacific Martens on the Lassen National Forest, California
Matthew Delheimer; Katie Moriarty; Marie Martin; Patrick Tweedy
Rest structures are critical features on the landscape for small forest carnivores like Pacific martens (Martes caurina), providing a secure location to avoid predators, consume prey, and reduce thermal stress. Rest structure selection by martens has been well studied; for example, martens use live trees, snags, and logs that are typically much larger than available structures. There is little information on marten reuse rates of such structures, with existing research generally indicating low (5-30%) reuse rates. Given the cryptic behavior of martens and the logistical challenges associated with telemetry studies, we hypothesized that reuse rates quantified solely via VHF telemetry may be incorrect. Between November 2015 and April 2017, we employed a combination of VHF telemetry and remote cameras to estimate short-term (<2 years) reuse rates of rest structures by martens on the Lassen National Forest, California. Using VHF telemetry, we identified 200 unique rest structures used by 19 VHF radio-collared martens (11M: 8F) and documented a reuse rate of 38%. We monitored a subset of these structures (n=104) with remote cameras for 3-12 months and documented a reuse rate of 86%. Our results suggest that reuse rates identified via VHF telemetry alone are inaccurate and that monitoring with multiple methods increased our ability to detect reuse events. Identifying physical attributes of the most frequently used rest structures can better inform forest management strategies. Targeting structures with similar attributes for retention and recruitment may increase long-term sustainability of local marten populations.
2:50PM Refreshment Break
3:20PM Distinguishing Reintroduction from Recolonization with Genetic Testing
Frances Stewart; John Volpe; John Taylor; Jeff Bowman; Philippe Thomas; Margo Pybus; Jason T. Fisher
Distinguishing reintroduction from recolonization with genetic testing Reintroductions are a common tool for restoring lost biodiversity around the globe and across taxa. The decision to pursue a reintroduction is often based upon the success of past efforts, yet in most cases the hypothesis that revived populations are the products of recolonization, is not tested. By collecting data from source populations, reintroduced populations, and natural populations adjacent to reintroductions, it is possible to evaluate the success of past reintroduction events and these data may be used to guide future conservation initiatives. We used the fisher (Pekania pennanti), one of North America’s most commonly reintroduced species, as a model to conduct an evaluation of reintroduction success. We genotyped 147 individuals at 15 microsatellite loci to determine the genetic contribution of reintroduced individuals to an ostensibly successfully reintroduced population in central Alberta, Canada. Principle component analysis and Bayesian statistical methods converged with confidence on one result: assayed individuals were descended from adjacent native Albertan populations, not putative founders from eastern Canada. A review of fisher reintroduction literature reveals similar patterns: a large proportion of contemporary individuals appear to be the result of recolonization events. Our study has broad implications for conservation as it suggests 1) over-confidence in past reintroductions, which might lead to significant expenditure of financial and human capital on future initiatives of modest, if any, benefit, and 2) underestimation of species’ ability to disperse and (re-) colonize, highlighting limits to our understanding of functional connectivity. Obtaining genetic samples from reintroductions with even minute probabilities of re-colonization will help determine when reintroduction is likely to be the best conservation initiative.
3:40PM Niche Overlap of Competing Carnivores Across Climactic Gradients and the Conservation Implications of Climate Change at Geographic Range Margins.
Jody M. Tucker; William J. Zielinski; Kerry M. Rennie
There is considerable interest in factors controlling “warm-edge” limits – the lower elevation and latitudinal edges of a species’ range. Understanding whether conservation measures can mitigate anticipated change in climate requires consideration of future climate as well as species interactions. We explored niche relations of martens (Martes caurina) and fishers (Pekania pennanti) at their southern range margins to understand their spatial and temporal dynamics, and how they may be affected by climate change. We used large-scale non-invasive surveys and home range data from radio-marked individuals to explore the spatial dynamics of each species. Marten and fisher were allopatric in the northern/wetter regions but sympatric at intermediate latitudes with lower precipitation. In the driest/southernmost region only fishers occurred. Martens were not detected when annual precipitation was < 900 mm and rare where minimum temperatures exceeded 4ºC. Fishers were absent where spring snow was > 650 mm. Classification trees, accounting for multivariate interactions, supported these results. Where sympatric, ~70% of a marten’s home range overlapped with at least one fisher but martens tended to avoid this area. In sympatry, marten expanded their niche into areas with reduced snowpack, warmer temperatures and uncharacteristic lower elevation habitats. Future climate scenarios predict conditions that favor fishers, but our data suggest martens may be capable of shifting their niche somewhat to warmer and less snowy habitats. The conservation of interacting species at their warm range limits will require land managers be aware of interspecific tolerance, how each may respond uniquely to future climates, and how potential climate refugia can be integrated with existing habitat.
4:00PM Fisher Reproductive Parameters in the Southern Sierra Nevada Relative to the Broader Range
Rebecca E. Green; Kathryn L. Purcell; Craig M. Thompson; Douglas A. Kelt; Heiko U. Wittmer
Quantifying reproductive parameters is essential to develop conservation plans for species of concern; however, studying reproduction in wild settings can be challenging thus local data frequently are unavailable. The fisher (Pekania pennanti) is an elusive forest-dwelling carnivore of conservation concern that occurs across much of boreal North America, reaching the southernmost limit of its distribution in the Sierra Nevada of California. Data on fisher reproduction in this region are limited and applicability of parameters from other areas uncertain. Our objectives were to review literature on fisher reproduction over the species’ range and compare these findings with data we collected over 7 years in the southern Sierra Nevada; we emphasize 1) the proportion of females reproducing, 2) parturition date, and 3) litter size. On average across its range, 71% of adult females reproduced (range, 40 – 100%; n = 16), parturition occurred on 25 March (total range, 3 March – 17 April; n = 16), and litter size was 2.5 (total range, 1 – 4; n = 16). In our study area, we used radio-telemetry to track 42 adult female fishers, 35 of which used 257 reproductive dens; 0.86 (range, 0.79 – 1.0) of females attempted denning and 0.75 (range, 0.64 – 1.0) were successful. Mean parturition date was 30 March (range, 17 March – 12 April; n = 69), and mean litter size was 1.57 (range, 1 – 3; n = 75). Hence, female fishers at the southern limit of their distribution reproduced at a rate comparable to or higher than elsewhere in North America, and gave birth at similar or later dates. Average litter size, however, was the lowest reported for the species, suggesting limited capacity to rebound from extrinsic threats. We discuss conservation implications and explore patterns of variation in litter size relative to climate and body weight.
4:20PM Subsistence Livelihoods Have Low Impact on Mammalian Occupancy in Southeastern Nicaragua Despite Widespread Declines.
Lauren T. Phillips; Gerald R. Urquhart; Robert A. Montgomery
In tropical regions, reliance on protected areas to conserve wildlife has come under increased criticism. Remote communities on the southeastern coast of Nicaragua are shifting from predominantly fisheries-based livelihoods to forest-based—creating challenges for conservation of terrestrial mammals. We hypothesized that as hunting and farming pressure increased, occupancy would decrease due to increasing human pressures on the forest. We expected large-bodied mammals to experience the greatest decrease in occupancy, followed by meso-carnivores and, ultimately, generalist prey species. We placed cameras in lowland rainforest adjacent to nine small villages to capture images of terrestrial mammals at 80 unique sites in 2010, 2012 and 2014. We analyzed detection/non-detection data using single-season occupancy models with disturbance, livelihood, and interaction covariates. In 2010 and 2014, occupancy of low-sensitivity species (agouti, paca, armadillo, coati, white-tailed deer) was affected by distance from road (-), distance from coastline (+), and the interaction between livelihood and distance from community (+). Moderate-sensitivity species (ocelot, margay, jaguarundi, tayra, collared peccary) were only affected by gathering (+) and distance from road and coastline (+). High-sensitivity species (jaguar, puma, tapir, white-lipped peccary, red brocket deer) were affected by distance from road (+) and distance from fresh water (- 2010, + 2014). These effects are closely related to the increasing human presence in the region. The increase in farming likely provided food and edge habitat to support generalist herbivores in the low-sensitivity group, preventing rapid decline and supporting mesocarnivores within the moderate-sensitivity group. High-sensitivity species persisted at low occupancy throughout the study but responded negatively to riparian development. These results indicate that while the impact of subsistence livelihoods on occupancy is low, the effect of an advancing cattle-ranching frontier may be very high and warrants immediate action to prevent further decline in mammalian occupancy.
4:40PM Finding the Eastern Spotted Skunk: Developing a Non-Invasive Hair Snare Method for the Collection of Eastern Spotted Skunk Genetic Material
Brian S. Wuertz; Geriann Albers; Colleen Olfenbuttel; Casey Gray; Ryan Sparks; Andrew Kota; Liesl Erb
Detectionof small carnivores is oftendifficult giventheir nocturnal behavior and avoidance of humans. These species become evenmore elusive as their numbers decline, and studying them canbecome more time-intensive and costly. The easternspotted skunk ( Spilogaleputorius )was once acommonfurbearer species withinits historic range of the United States, but is now indecline. Inresponse, the IUCN changed its status from “Least Concern”to “Vulnerable”in2016as populations become increasingly fragmented and locally extirpated. Conservationefforts are hindered by alack of knowledge about the general life history traits and current status of spotted skunk populations. InNorth Carolina, there have beenjust afew spotted skunk detections viatrail cameras, but the extent of occupancy inthe state is unknown. We developed anon-invasive hair snare method for collecting genetic material from spotted skunks for populationanalysis. The method is analternative tolive mark-recapture studies and may reduce bias due totrap-shy or trap-happy individuals. We tested hair snare designs paired with trail cameras inareas with and without records of spotted skunks inwesternNorth Carolina. We evaluated the effectiveness of the hair snare designs based onpermeability toand selectivity for easternspotted skunks, the amount of genetic material obtained per visitation, and the ease of use by researchers. Intotal, we collected 40hair samples over 52trap-nights, identifying at least eight unique spotted skunk individuals. Glue elements inthe snare resulted inmore genetic material collected per skunk visit thanany combinationof wire brushes. The relatively low cost of this device gives it the potential for widespread use across the species’ range toestimate populationsizes, identify genetic bottlenecks, and compare the genetics of subspecies, which will helpclose knowledge gaps and inform wildlife management decisions.

 

Contributed Paper
Location: Albuquerque Convention Center Date: September 25, 2017 Time: 1:10 pm - 5:00 pm