Lessons Learned From a 20-Year Collaborative Study on American Black Bears

In the 1980s, black bears (Ursus americanus) began expanding into historic habitats in northwestern Nevada, USA. Over a period of \u3e30 years, black bears recolonized areas where human populations have also increased. Our research represents one of, if not the longest-running and earliest comparative studies of a black bear population at wildland–urban interface and wildland areas in North America. As the population increased, we observed: 1) increasing human–bear conflicts in areas where several generations of people had lived in almost total absence of bears (70–80+ years); 2) changes in attitudes by the public toward bears and in the social realm regarding garbage management; and 3) changes in the demographics, behavior, and ecology of this bear population, due to an increasing human footprint on the landscape. Herein, we discuss a few of the lessons learned from this long-term study and the value of a collaborative approach between a state agency, a university, and an international conservation organization. Our collaborative approach allowed us to better understand the ecological, demographic, and behavioral changes in a large, recolonizing carnivore that is a functional omnivore, often residing at the wildland-urban interface, and to use these data to impact conservation and management. Throughout the study, our data were used extensively by various media, emphasizing public education about human–bear conflicts. This media platform proved important because of the impact it had on wildlife conservation. For example, partly in response to media coverage of our data-based education efforts, 3 Nevada counties enacted garbage management ordinances, and the Nevada legislature passed a state law prohibiting the feeding of large game mammals. Further, several million dollars in bear-resistant garbage containers are now used in the region by the public and government entities. The end result of these conservation measures has been a recolonization of the Great Basin Desert by bears from the Lake Tahoe Basin and Sierra-Nevada Range into portions of Nevada where bears have been absent for \u3e80 years

Influence of Habitat on Distribution and Abundance of the Eastern Woodrat in Kansas

Anthropogenic modification of native woodlands and grasslands in the Great Plains has altered the abundance and distribution of many species of mammals. To study habitat effects on the eastern woodrat (Neotoma floridana), we surveyed nests of the eastern woodrat in woodlands, grasslands, and croplands along 77 km of secondary roads in three counties in north-central Kansas. All nests were located in woodlands ( \u3c 2 %of habitat), although grasslands and croplands constituted 36% and 62% of habitat surveyed, respectively. In our survey, nests were associated positively with shelterbelts (3.6 nests per 100 m of road edge) but not with shrub patches (1.1 nests per 100 m of road edge) or riparian woodlands (0.3 nests per 100 m of road edge). Consequently, we specifically censused nests in an additional 12 riparian woodlands and 12 shelterbelts. Nests of eastern woodrats were less dense in riparian woodlands (9.4 nests/ha) than in shelterbelts (55.5 nests/ha). Density of woodrat nests decreased as width of a wooded area increased. Further, nests per 100 m of length of woodland did not increase as the width of woodland increased. These patterns suggest that woodland edge, not woodland interior, is the primary factor in abundance of eastern woodrats in this region. Although the eastern woodrat has previously been considered a woodland species, our results suggest that this assessment is incorrect. Our observations demonstrate that anthropogenic modification of the Great Plains, in the form of planted shelterbelts and expanded riparian woodland, likely has increased the distribution and abundance of eastern woodrats, compared to the mid-1800s

Identification of source-sink dynamics in mountain lions of the Great Basin

Natural and anthropogenic boundaries have been shown to affect population dynamics and population structure for many species with movement patterns at the landscape level. Understanding population boundaries and movement rates in the field for species that are cryptic and occur at low densities is often extremely difficult and logistically prohibitive; however genetic techniques may offer insights that have previously been unattainable. We analyzed thirteen microsatellite loci for 739 mountain lions (Puma concolor) using muscle tissue samples from individuals in the Great Basin throughout Nevada and the Sierra Nevada mountain range to test the hypothesis that heterogeneous hunting pressure results in source-sink dynamics at the landscape scale. We used a combination of non-spatial and spatial model-based Bayesian clustering methods to identify genetic populations. We then used a recently developed Bayesian multilocus genotyping method to estimate asymmetrical rates of contemporary movement between those subpopulations and to identify source and sink populations. We identified two populations at the highest level of genetic structuring with a total of five subpopulations in the Great Basin of Nevada and the Sierra Nevada range. Our results suggest that source-sink dynamics occur at landscape scales for wide-ranging species, such as mountain lions, and that source populations may be those that are under relatively less hunting pressure and that occupy refugia

Highways, crossing structures and risk: Behaviors of Greater Yellowstone pronghorn elucidate efficacy of road mitigation

Wildlife crossing structures and accompanying barrier fencing can prevent large mammals from accessing road surfaces and can significantly reduce wildlife-vehicle collisions while allowing animals to move from one side of the road to the other. Little research has been conducted on the behavioral responses of wildlife when encountering these novel structures over time. We used the installation of new wildlife road crossing structures built along a 6000-year old migration route to evaluate behavioral responses of long-distance migrators to the structures. We collected behavioral data during and after construction in order to evaluate individuals' immediate responses to these structures and to investigate how they changed over time using generalized linear mixed-effects models and generalized additive models fit by maximum likelihood. Pronghorn acclimated to the crossing structures and the frequency in which they successfully crossed them increased over time. The probability of pronghorn successfully crossing a structure was not influenced by human presence. Pronghorn spent more time in sustained vigilance behaviors after construction. Pronghorn also spent more time in sustained vigilance behaviors at relatively further distances from a structure and lead individuals spent more time in sustained vigilance behaviors than non-lead individuals. We did not detect any significant factors associated with stress behaviors. Pronghorn still demonstrated high sustained vigilance when approaching the structures after 20 months post construction, despite an increase in crossing success. While we found evidence of risk-avoidance behaviors in pronghorn at crossing structures, this work provides evidence that pronghorn gradually acclimated to wildlife crossing structures built in a historical migration corridor in the Greater Yellowstone Ecosystem. We recommend using task completion chronology (rather than project completion dates) to install wildlife mitigation and we recommend using wildlife friendly fencing when fences are required for multiple use (e.g., cattle) at crossing structure entrances. (C) 2018 The Authors. Published by Elsevier B.V

Recolonizing carnivores: Is cougar predation behaviorally mediated by bears?

Conservation and management efforts have resulted in population increases and range expansions for some apex predators, potentially changing trophic cascades and foraging behavior. Changes in sympatric carnivore and dominant scavenger populations provide opportunities to assess how carnivores affect one another. Cougars (Puma concolor) were the apex predator in the Great Basin of Nevada, USA, for over 80 years. Black bears (Ursus americanus) have recently recolonized the area and are known to heavily scavenge on cougar kills. To evaluate the impacts of sympatric, recolonizing bears on cougar foraging behavior in the Great Basin, we investigated kill sites of 31 cougars between 2009 and 2017 across a range of bear densities. We modeled the variation in feeding bout duration (number of nights spent feeding on a prey item) and the proportion of primary prey, mule deer (Odocoileus hemionus), in cougar diets using mixed-effects models. We found that feeding bout duration was driven primarily by the size of the prey item being consumed, local bear density, and the presence of dependent kittens. The proportion of mule deer in cougar diet across all study areas declined over time, was lower for male cougars, increased with the presence of dependent kittens, and increased with higher bear densities. In sites with feral horses (Equus ferus), a novel large prey, cougar consumption of feral horses increased over time. Our results suggest that higher bear densities over time may reduce cougar feeding bout durations and influence the prey selection trade-off for cougars when alternative, but more dangerous, large prey are available. Shifts in foraging behavior in multicarnivore systems can have cascading effects on prey selection. This study highlights the importance of measuring the impacts of sympatric apex predators and dominant scavengers on a shared resource base, providing a foundation for monitoring dynamic multipredator/scavenger systems

Artificial Nightlight Alters the Predator–Prey Dynamics of an Apex Carnivore

Artificial nightlight is increasingly recognized as an important environmental disturbance that influences the habitats and fitness of numerous species. However, its effects on wide‐ranging vertebrates and their interactions remain unclear. Light pollution has the potential to amplify land‐use change, and as such, answering the question of how this sensory stimulant affects behavior and habitat use of species valued for their ecological roles and economic impacts is critical for conservation and land‐use planning. Here, we combined satellite‐derived estimates of light pollution, with GPS‐data from cougars Puma concolor (n = 56), mule deer Odocoileus hemionus (n = 263) and locations of cougar‐killed deer (n = 1562 carcasses), to assess the effects of light exposure on mammal behavior and predator–prey relationships across wildland–urban gradients in the southwestern United States. Our results indicate that deer used the anthropogenic environments to access forage and were more active at night than their wildland conspecifics. Despite higher nightlight levels, cougars killed deer at the wildland–urban interface, but hunted them in the relatively darkest locations. Light had the greatest effect of all covariates on where cougars killed deer at the wildland–urban interface. Both species exhibited functional responses to light pollution at fine scales; individual cougars and deer with less light exposure increasingly avoided illuminated areas when exposed to greater radiance, whereas deer living in the wildland–urban interface selected elevated light levels. We conclude that integrating estimates of light pollution into ecological studies provides crucial insights into how the dynamic human footprint can alter animal behavior and ecosystem function across spatial scales

Sex-stratified Genome-wide Association Studies Including 270,000 Individuals Show Sexual Dimorphism in Genetic Loci for Anthropometric Traits

Peer reviewe

Carnivores, urban landscapes, and longitudinal studies: a case history of black bears

As urban landscapes expand across the globe, it becomes imperative to understand how these landscapes affect large carnivore populations. We examined the effects of human-altered landscapes on age-specific fecundity and life history parameters for female black bears (Ursus americanus) in urban and wildland regions in the northern Sierra Nevada Mountains of Nevada, including the Lake Tahoe Basin. We followed 12 marked female bears in an urban environment and 10 females in wildland habitats from 1997–2006. Our results show that female bears in urban areas have higher age-specific fecundity rates than did wildland female bears. Despite this difference, female bears in urban areas never realized this putative gain in fitness because they experienced higher age-specific mortality rates, leading to the creation of sinks (λ = 0.749). Urban bears of the Lake Tahoe Basin are unable to repopulate vacated wildland areas

Changes in Pronghorn Use of a Natural Gas Field in Greater Yellowstone

Among Earth’s most stunning, yet imperiled, biological phenomenon is Long Distance Migration. Of 17 terrestrial mammals in North America for which migration data exist, pronghorn (Antilocapra americana) of the Upper Green River Basin of western Wyoming have the most extreme movements between Argentina and central Canada and the second longest migration in the entire western hemisphere. This extensive migration approaches 400-500 km on an annual, round-trip basis, and necessitates crossing multiple jurisdictional/political boundaries and the use of four historically narrow bottlenecks (0.2 – 0.8 km) that have existed for almost 6000 years. The impressive movements by pronghorn from relatively xeric areas of the Upper Green River Basin to Grand Teton National Park are comparable with the well-known migratory treks of African wildebeest, zebras, and elephants. To manage America’s 991,479 km2 (245 million acres) of public BLM lands for such mixed uses as natural resource extraction, wildlife, and recreation requires knowledge about effects of habitat alterations. Two of North America’s largest natural gas fields occur in the southern region of the Greater Yellowstone Ecosystem (Wyoming), an area that contains \u3e100,000 wintering ungulates, including crucial winter range for pronghorn of Grand Teton National Park. During a 5-year period (2005–2009), we concentrated on patterns of habitat selection of pronghorn to understand how winter weather and increasing habitat loss due to gas field development impact habitat selection. Since this population is held below a food ceiling (i.e., carrying capacity) by human harvest, we expected few habitat constraints on animal movements – hence we examined fine-scale habitat use in relationship to progressive energy footprints. We used mixed-effects resource selection function models on 125 GPS-collared female pronghorn, and analyzed a comprehensive set of factors that included habitat (e.g., slope, plant cover type) and variables examining the impact of gas field infrastructure and human activity (e.g., distance to nearest road and well pad, amount of habitat loss due to conversion to a road or well pad) inside gas fields. Our RSF models demonstrate: (1) a five-fold sequential decrease in habitat patches predicted to be of high use and (2) sequential fine-scale abandonment by pronghorn of areas with the greatest habitat loss and greatest industrial footprint. The ability to detect behavioral impacts may be a better sentinel and earlier warning for burgeoning impacts of resource extraction on wildlife populations than studies focused solely on demography. Nevertheless disentangling cause and effect through the use of behavior warrants further investigation. Jon P. Beckmann, Wildlife Conservation Society, North America Program, 301 N Willson Ave., Bozeman, MT 59715, [email protected] As a Conservation Scientist at WCS, Jon is the Connectivity Initiative Coordinator for the North America Program. He is also Principle Investigator on several projects in the Greater Yellowstone Ecosystem (GYE) and in other regions of North America. Jon’s current research projects include: 1) examining the impacts of natural gas development on pronghorn of western Wyoming; 2) protecting ungulate migrations in the northern Rockies by understanding and reducing wildlife-vehicle collisions; 3) an on-going 15-year study investigating and reducing human-bear conflicts along the wildland-urban interface in the Lake Tahoe Basin; 4) using detection dogs, resource selection and circuit theory modeling to examine connectivity for large carnivores in the GYE; 5) examining the impacts of the US-Mexico border fence on carnivore connectivity; and 6) understanding how human-altered environments impact mountain lion ecology in the Great Basin. Along with numerous publications, Dr. Beckmann is lead editor on a book titled Safe Passages: highways, wildlife and habitat connectivity