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 analysed 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.

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.

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Cougars (Puma concolor) occupy mountain ranges throughout the Great Basin, Nevada, USA, where legal trapping of bobcats (Lynx rufus) is common and some non‐target captures of cougars in bobcat traps occur. Such incidental capture of cougars is an undocumented source of mortality because some cougars die from injuries several weeks after release from traps. We examined cause‐specific mortality and the effects of capture of cougars in bobcat traps on annual and overall (7‐year) survival during 2009–2015. We captured 48 cougars, of which we followed 33 until death. We estimated average annual survival rates for adult cougars and assessed the relative effects of sex, season, and long‐term effects of non‐target capture of cougars in foothold traps on estimated survival of adults using a nest survival model in Program MARK. We incorporated a time‐varying covariate to assess the long‐term effect of capture in non‐target foothold traps on survival of adult cougars. Average annual survival of non‐trapped females and males, regardless of trapping history, was significantly greater than females with a history of capture in a non‐target foothold trap; however, once partitioned across age, sex, and capture status, sample sizes were small. Our results suggest that capture in non‐target foothold traps decreases survival of adult female cougars directly by causing injuries that eventually result in mortality, and indirectly by increasing susceptibility to other forms of mortality. Mortality of adult females during the 7 years of our study caused by non‐target trapping was similar to hunting among radio‐marked female cougars, and this potential source of mortality has been unaccounted for in harvest objectives and harvest data for cougars without radio‐collars. Given anthropogenic sources of mortality accounted for 100% of recorded mortality of adult females, mortality from non‐target trapping is likely additive to other sources of mortality in our study area. We recommend regulatory agencies consider the possibility of unintentional take and potential for reduced long‐term survival of females where these large fields are sympatric with bobcats, and trapping of bobcats with foothold traps is a legal activity. Moreover, we suggest wildlife managers record information about the trapping incident, to include trap type, trap size, trap set type, location, number of days since last check, and type and severity of injuries when releasing incidentally captured cougars to inform future management decisions. Addressing other anthropogenic sources of mortality resulting from conflict with humans and road mortalities will be increasingly important as the human population expands into cougar habitat. © 2018 The Wildlife Society.

Natural controls on the distribution, abundance, or growth rates of exotic species are a desirable mode of intervention because of lower costs compared to anthropogenic controls and greater social acceptance. In the Great Basin, cougars (Puma concolor) are the most widely distributed carnivore capable of killing large ungulate prey. Populations of feral horses (Equus ferus) are widely distributed throughout the Great Basin and can grow at rates up to 20%/year. Although cougars exhibit distributional overlap with horses, it has been assumed that predation is minimal because of differences in habitat use and body-size limitations. To evaluate this hypothesis, we monitored the diets of 21 global positioning system (GPS)-collared cougars in the western Great Basin (5 males, 8 females) and eastern Sierra Nevada (2 males, 6 females) from 2009-2012. We investigated 1,310 potential kill sites and located prey remains of 820 predation events. We compared prey composition and kill rates of cougars inhabiting the Sierra Nevada and Great Basin, and among male and female cougars across seasons. We used generalized linear mixed models (GLMMs) to examine the effects of prey availability and habitat characteristics on the probability of predation on horses by cougars. Mule deer (Odocoileus hemionus) comprised 91% of prey items killed on the Sierra Nevada reference site but only comprised 29% of prey items in the Great Basin study area. Average annual kill rates for deer differed between the Sierra Nevada (x = 0.85 deer/week, range = 0.44-1.3) and Great Basin (x = 0.21 deer/week, range = 0.00-0.43). Diets of cougars in the Great Basin were composed predominantly of horses (59.6%, n = 460 prey items; 13 individuals). Ten cougars regularly consumed horses, and horses were the most abundant prey in the diet of 8 additional individuals in the Great Basin. Cougars on average killed 0.38 horses/week in the Great Basin (range = 0.00-0.94 horses/week). Differences in predation on horses between the sexes of cougars were striking; Great Basin females incorporated more horses across all age classes year-round, whereas male cougars tended to exploit neonatal young during spring and summer before switching to deer during winter. Within GLMM models, the probability of predation on horses compared to other prey species increased with elevation, horse density, and decreasing density of mule deer on the landscape, and was more likely to occur in sagebrush (Artemesia spp.) than in pinyon (Pinus monophylla)-juniper (Juniperus osteosperma) forests. Behavior of individual cougars accounted for more than a third of the variation explained by our top models predicting predation on horses in the Great Basin. At landscape scales, cougar predation is unlikely to limit the growth of feral horse populations. In the Great Basin ecosystem, however, cougars of both sexes successfully preyed on horses of all age classes. Moreover, some reproductive, female cougars were almost entirely dependent on feral horses year-round. Taken together, our data suggest that ...