Population demographics of cougars in the Black Hills: Survival, dispersal, morphometry, genetic structure, and associated interactions with density dependence

The cougar (Puma concolor) is the remnant apex predator of South Dakota. Cougars were extirpated from the majority of the Dakotas by the early 1900s, and severely reduced or extirpated from the Black Hills of South Dakota and Wyoming during this same time. Many factors led to the demise of cougars throughout North America, but cougars proved resilient. A few sporadic sightings were recorded in the Black Hills during the 20 th century, with enough verified sightings occurring during the 1980s that the South Dakota Department of Game, Fish and Parks began recording sightings and verifying potential cougars. Verified reports continued and research was initiated in 1998 to document distribution and abundance of the species in the Black Hills. Early research efforts spawned the research that is included in this dissertation. The cougar population of the Black Hills rebounded to that of a viable breeding cougar population and is unique in that it naturally reestablished and also is semi-isolated from extant cougar populations. Our research encompassed the Black Hills of South Dakota and Wyoming (approximately 8,400 km2). Primary objectives were to: (1) document cougar survival by sex and age class and characterize mortality of an unhunted cougar population, (2) document dispersal movements and assess philopatry of a cougar population semi-isolated from other populations in a mountainous region surrounded by atypical cougar habitat, (3) assess the genetic structure of a semi-isolated cougar population, (4) document morphological attributes of a newly recolonized cougar population, and (5) assess population status and document effects of density dependence as they relate to overall population demographics of the cougar population in the Black Hills. Cougars were captured and fitted with radio-transmitters to assess these objectives as well as acquiring ancillary data through sightings, reported mortalities, and cooperative efforts from many management agencies across several jurisdictional boundaries. Annual survival of independent adult cougars averaged 0.87 (range: 0.50--1.0 annually); no difference in survival (P = 0.83) occurred between adult males and females. Subadult males had the lowest survival rate (0.62) of any sex/age class in our study area. Kitten survival was 0.67. We documented 85 mortality events in South Dakota from 1998--2005. Vehicles (32.9%) and depredation removals (21.2%) accounted for most cougar mortality in the Black Hills, with 85% of mortality being human-induced. Males dispersed (Mean = 274.7 km SE 88.3) farther than females (Mean = 48.0 km SE 10.9), with females exhibiting 40% philopatry. No subadult males were recruited into the Black Hills cougar population. We documented several (n = 6) long-distance dispersal movements (>200 km) of male cougars and hypothesize that males making long-distance movements were in search of available mates. Movements documented by our study indicate that cougar range expansion and habitat recolonization are occurring. Cougars in the Black Hills were comparable in size and weight to cougar populations in western North America. Regression analyses indicated that plantar pad width from front and hind feet were accurate indicators of sex of cougars > 1 year of age. Accurate measurements from reliable tracks may be useful for biologists to assess gender; however, age does not correlate as well with track dimensions. Although cougars in the Black Hills showed a marginally significant genetic bottleneck, they do not appear to have deleterious effects from the event. Cougars in South Dakota had an average expected heterozygosity (HE) of 0.542 and observed heterozygosity (HO) of 0.547. Effective population size (Ne) of Black Hills cougars was 28 individuals (23--39; 95% CL). Based on our results, there is adequate power to discern individual cougars from geographically close (< 200 km) populations using 20 loci, and we recommend that a large-scale genetic database of cougars at an international level be constructed to assess genetic structure and population demographic across the species' distribution. We identified several primary factors indicating density dependent effects on cougars in the Black Hills: decrease in female home-range size, increased home-range overlap, increased female dispersal and decreased philopatry, neonate sex ratios skewed to male, increased mortality related to intraspecific strife, infanticide and emaciation, and a decrease in body condition. Results will be used to assess initiation of harvest on the cougar population in the Black Hills as well as serving as fundamental baseline data to evaluate the status of the population in the future and assessment of management strategies to maintain the population in perpetuity.