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Currently, 11 western states and 2 Canadian provinces use sport hunting as the primary mechanism for managing cougar (Puma concolor) populations. Yet the impacts of sustained harvest on cougar population dynamics and demographic structure are not well understood. We evaluated the effects of hunting on cougar populations by comparing the dynamics and demographic composition of 2 populations exposed to different levels of harvest. We monitored the cougar populations on Monroe Mountain in south‐central Utah, USA, and in the Oquirrh Mountains of north‐central Utah from 1996 to 2004. Over this interval the Monroe population was subjected to annual removals ranging from 17.6–51.5% (mean ± SE = 35.4 6 4.3%) of the population, resulting in a >60% decline in cougar population density. Concurrently, the Oquirrh study area was closed to hunting and the population remained stationary. Mean age in the hunted population was lower than in the protected population (F = 9.0; df = 1, 60.3; P = 0.004), and in a pooled sample of all study animals, females were olderthan males (F = 13.8; df = 1, 60.3; P < 0.001). Females from the hunted population were significantly younger than those from the protected population (3.7 vs. 5.9 yr), whereas male ages did not differ between sites (3.1 vs. 3.4 yr), suggesting that male spatial requirements may put a lower limit on the area necessary to protect a subpopulation. Survival tracked trends in density on both sites. Levels of human‐caused mortality were significantly different between sites (χ2 = 7.5; P = 0.006). Fecundity rates were highly variable in the protected population but appeared to track density trends with a 1‐yearlag on the hunted site. Results indicate that harvest exceeding 40% of the population, sustained for ≥4 years, can have significant impacts on cougar population dynamics and demographic composition. Patterns of recruitment resembled a source–sink population structure due in part to spatially variable management strategies. Based on these observations, the temporal scale of population recovery will most likely be a function of local harvest levels, the productivity of potential source populations, and the degree of landscape connectivity among demes. Under these conditions the metapopulation perspective holds promise for broad‐scale management of this species.

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.

Numerous techniques have been proposed to estimate or index cougar (Puma concolor) populations, but few have been applied simultaneously to populations with reliable estimates of population size. Between 1996 and 2003, we evaluated the relative efficacy and accuracy of multiple estimation and index techniques for populations at 2 locations in Utah, USA: Monroe Mountain and the Oquirrh Mountains. We used radiotagging followed by intensive monitoring and repeated capture efforts to approach a complete enumeration of the populations. We used these benchmarks to evaluate other population estimates (Lincoln—Petersen mark—recapture, helicopter‐survey probability sampling, catch‐per‐unit‐effort) and indices (scent‐station visits, track counts, hunter harvest). Monitoring over 600 scent‐station‐nights using different attractants June—September in 1996 and 1997 yielded a single cougar visit. Summer track‐based indices reflected a 54–69% reduction in population size on the Monroe site and a numerically stable population on the Oquirrhs, but relationships between indices and the benchmark population estimates varied among techniques. Aerial track surveys required sufficient fresh snowfall accumulations for adequate tracking coverage of a given unit, conditions that were met only once on one study site in each of 3 years. Population estimates derived from helicopter‐survey probability sampling exceeded reference population estimates by 120–284%, and bootstrapped estimates of standard error encompassed 25–55% of the population estimates (e.g., 5.6 ± 1.4 cougars/100 km2). Despite poor performance in predicting cougar population sizes, track‐based estimates may provide better indices for monitoring large changes in population trends (i.e., with low precision). However, we recommend using multiple indices after determination of a more rigorous initial population estimate for managing populations of conservation concern and when considering connectivity to determine potential refuge sites for regional management (e.g., management by zones).

We present results from a study of genetic variation in Utah's cougar population. Estimates were based on data for 50 animals at nine microsatellite loci with five individuals sampled for each of ten management units throughout Utah. Levels of variation were moderate (average genetic diversity across populations was estimated to be 0.4687 for all 50 individuals), and comparable with other large mammals. But this level of variation for the microsatellite loci translated into an inbreeding effective population size of only 571 animals, much lower than the current estimates of census sizes of around 2000-3000. A lack of differentiation among the sampled populations across Utah (average N e m = 6.2) indicates that gene flow occurs over a large area. Since cougars are capable of movement beyond the Utah state borders (and certainly across management units), a better understanding of migration rates and patterns of dispersal will be achieved by sampling a much larger geographic region incorporating much of the western USA. Successful management and conservation of this species will then require a far more integrated approach, involving agencies across a number of states, as opposed to current management practices involving individual units within states.

a b s t r a c tUnderstanding the interplay between exploitation and natural mortality is essential to guiding sustainable conservation of wildlife. Exploitation of carnivores by humans has long been thought to result in compensatory reductions of natural mortality among survivors. If rates of human exploitation exceed natural mortality, however, such actions will 'add' to overall mortality and could imperil the sustainability of such actions. We applied competing risk analyses to P16 years of data for heavily harvested and semi-protected cougar populations in Utah to test the additive and compensatory mortality hypotheses, while accounting for parameter uncertainty. We additionally tested for presence of the two primary mechanisms by which compensatory mortality can arise: density dependence and individual heterogeneity in mortality risks. Despite an opportunity for compensation in the heavily harvested population, we could not reject the additive mortality hypothesis when uncertainty in parameter estimates was accounted for. In the semi-protected population, however, we detected evidence for partial compensation of increased anthropogenic exploitation via reductions in natural mortality. As may be common in carnivore studies, we found that ignoring uncertainty in estimates of cause-specific mortality systematically led to biased conclusions regarding additive and compensatory mortality hypotheses. Efforts should be made to address and minimize this uncertainty in demographic studies of carnivores in order to avoid flawed management recommendations. To attain the necessary sample sizes for making sound inference, this may require that the spatial extent of management units be extended for territorial species with large home-range requirements.

The source‐sink model of population dynamics predicts that density drives emigration of subordinate animals to habitats offering lower competition for resources. Several authors have suggested use of this model as a potential framework for conservation of exploited carnivores when precise enumeration is unfeasible. Dispersal is a critical behavioural mechanism for management based on this model, yet there is a lack of knowledge on the habitat and social conditions that motivate carnivore emigration and settlement. The cougar Puma concolor is a widely distributed and heavily exploited carnivore, indigenous to the western hemisphere. We evaluated patterns in cougar dispersal behaviour from two sites in Utah, differing in terms of management and the level of natural and anthropogenic habitat fragmentation. We used our results to evaluate three predictions with respect to cougar dispersal behaviour: 1) natal population density and maternal reproductive status prompt emigration, 2) movement of dispersing cougars is shaped by habitat configuration and permeability, and 3) dispersers preferentially settle in areas of high habitat quality and low conspecific density. We documented the emigration of 62 individuals and measured movement variables, including sex and site‐specific frequency, distance, seasonality, direction and the habitat quality and harvest rates characterizing areas where immigrants settled. Although males and females exhibited pronounced differences in dispersal frequency, we found few differences in distance traveled, season of departure and direction moved. Dispersal occurred most frequently during spring, coinciding with the estrus pulse. Natural and anthropogenic obstacles modified landscape permeability, and therefore dispersal distances were shorter in fragmented habitats than in contiguous ones. Relative to males, females dispersed into habitats of lower productivity with higher mean annual harvest rates. Patterns in male settlement suggested habitat selection based on mating opportunities, whereas female settlement was predicated on avoiding conspecifics. Cougars in this Great Basin ecosystem largely conformed to source‐sink predictions. Results can be used to parameterize source‐sink models based on animal behaviour and landscape permeability to conserve exploited carnivores, under conditions of population expansion or recolonization of habitats where Allee effects are a limiting factor.

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