Population density estimates are necessary to inform management and conservation, yet are difficult to obtain for cryptic species such as carnivores, and often require intensive sampling. We implemented a single‐survey, closed session, scat sampling protocol to estimate bobcat density using fecal DNA and spatial capture‐recapture at two sites over five sessions in Virginia, USA. We employed a Poisson encounter model to allow for multiple detections on scat transect segments over a single collection interval, and compared single session and multistrata (closed, multi‐site, multisession) spatial capture‐recapture (SCR) approaches to estimate density for each site and session. We found improved precision for most estimates using the multistrata SCR approach, sharing data on baseline detection and individual movement across sites and sessions. We suggest the summer session estimates are representative of the resident population, that differences in density between summer and winter are representative of potential net recruitment, and that differences between consecutive summer sessions are representative of the net recruitment realized for the population (dependent on survival and emigration). Finally, we assessed factors affecting precision in single session model estimates and provide recommendations to improve detection and reduce credible intervals that may be applicable across the bobcat range and to other carnivore species. The single survey transect methodology provides flexibility in monitoring carnivore populations specifically, or as part of concurrent monitoring for multiple carnivore species. This methodology has potential to dramatically increase the effectiveness of conservation and management dollars, improving our ability to monitor carnivore populations and assess conservation needs and actions.
Across taxa, sex-specific demands vary temporally in accordance with reproductive investments. In solitary carnivores, females must provision and protect young independently while meeting increased energetic demands. Males seek to monopolize access to females by maintaining large territories and defending them from other males. For many species, it is poorly understood how these demands relate to broad-scale animal movements. To investigate predictions surrounding the reproductive strategies of solitary carnivores and effects of local conditions on bobcat (Lynx rufus) spatial ecology, we examined the effects of sex and reproductive season on home range size, movement rate, and resource selection of bobcats in the central Appalachian Mountains. Male seasonal home ranges were approximately 3 times larger than those of females (33.9 ± 2.6 vs. 12.1 ± 2.4 km 2 , x±SE), and male movement rates were 1.4 times greater than females (212.6 ± 3.6 vs. 155 ± 8.2 m/hr), likely reflecting male efforts to maximize access to females. Both sexes appear to maintain relatively stable seasonal home ranges despite temporally varying reproductive investments, instead adjusting movements within home ranges. Males increased movements during the dispersal period, potentially reflecting increased territoriality prior to breeding. Females increased movements during the kitten-rearing period, when foraging more intensively, and frequently returning to den sites. Both sexes selected home ranges at higher elevations. However, females selected deciduous forest and avoided fields, whereas males selected fields and avoided deciduous forest, perhaps explained by male pressure to access multiple females across several mountain ridges and higher risk tolerance. Seasonal changes in home range selection likely reflect changes in home range shape. Increased female avoidance of fields during kitten rearing may indicate female avoidance of presumably resource rich, yet risky, fields at the time when kittens are most vulnerable. Our results indicate that while reproductive chronology influences the spatial ecology of solitary carnivores, effects may be constrained by territoriality.
2 15 ABSTRACT 16 Bobcats are an apex predator and a species of socio-cultural importance in the central 17 Appalachian Mountains. Despite their importance, knowledge of bobcat spatial ecology in the 18 region is sparse. We examined space use and resource selection of bobcats in the Appalachian 19 Mountains of western Virginia during 3 biological seasons: breeding (January-March), kitten-20 rearing (April-September), and dispersal (October-December). We observed sex effects on all 21 space use metrics, with male seasonal areas of use (SAU) approximately 3 times larger than 22 female SAUs and male movement rates 1.5 times higher than females during all seasons. We 23 found no seasonal effect on SAU size for either sex. Female movement rates increased during the 24 kitten-rearing season, and male movement rates increased during the dispersal season. We 25 examined seasonal bobcat resource selection at 2 hierarchical scales, selection of home ranges 26 within the landscape (2 nd order) and selection of locations within home ranges (3 rd order).27 Female bobcats exhibited 2 nd order selection for higher elevations and deciduous forest and 28 avoidance of fields. Males exhibited 2 nd order selection for higher elevations and fields. Male 2 nd 29 order selection appears to be driven largely by the spatial distribution of females, which is 30 mediated through the valley and ridge topography of the study area. Sample size precluded 3 rd 31 order analysis for females, however males exhibited 3 rd order selection for higher elevations, 32 fields, and deciduous forest. Resource selection patterns varied seasonally for both sexes, 33 possibly driven by seasonal shifts in prey availability. Our findings highlight the importance of 34 forested ridges to bobcats in the region. Our findings also illustrate the differences in space use 35 between sexes, which future research efforts should consider. Further research should investigate 36 seasonal shifts in bobcat prey selection, which may further explain the seasonal resource 37 selection shifts we observed, and highlight potential implications for prey species. 3 38 41 An understanding of animal spatial ecology is critical for managing and conserving 42 wildlife populations [1,2]. Knowledge regarding space use and habitat requirements of wildlife 43 provides insight into fundamental ecological processes such as population dynamics, behavioral 44 interactions, and foraging behavior [3-5]. This information can be vital for informing wildlife 45 management decisions and understanding a species role within food webs may vary across space. 46 Bobcat (Lynx rufus) populations are increasing throughout much of their range, both 47 through recolonizing areas of previous extirpation and increasing in abundance where they have 48 persisted [6]. These trends are evident in the central Appalachian Mountains [6]. Although 49 bobcats largely persisted, wolves (Canis spp.) and cougars (Puma concolor) remain extirpated 50 from ecosystems in the Appalachian Mountains, leaving bobcats as an apex p...
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