Habitat use and population dynamics of bobcats in southern Illinois

Bobcat (Lynx rufus) ecology has been studied throughout their distributional range. However, the following aspects of bobcat ecology have not been studied or have received scant attention: (1) demography of unexploited and relatively isolated populations, (2) the influence of habitat physiognomy (e.g., cover-type interspersion) on habitat use, (3) habitat influences on home range and core area size, (4) large-scale habitat-population density relationships, and (5) theoretical modeling of dispersal and social organization in increasing populations. I used demographic and home range information from 76 radiocollared bobcats, bobcat sighting locations, univariate and multivariate statistics, remotely-sensed land cover data, a geographic information system (GIS), and computer programming as primary analysis techniques to address these paucities in the literature. My goals were to provide biologists with information to focus bobcat management in Illinois and to provide a better understanding of solitary carnivore ecology. Study-long survival estimates (range = 81--86%) and recruitment rates (0.63 kittens/Ad F) were among the highest reported for bobcats and resulted in a population density of 0.27 bobcats/km2 on the intensive study areas. I tested for sex-specific differences in habitat use among 4 classes of fixed kernel use-areas (home ranges and core areas for M and F). Five habitat variables were used similarly for both sexes, which implied territoriality may be a more important determinant of use-area placement within the sexes. However, intersexual differences existed, indicating that different habitat components were necessary to fulfill male and female life-history requirements. Habitat components predicted (P < 0.0001) size of all categories of use-area and accounted for 87--97% of the variance in use-area size. I created a regional habitat-population density relationship to assess distribution and abundance of bobcats in southern Illinois. Population density was relatively uniform across the study area, except for areas that consisted of a high proportion of agricultural cover. Highest county-wide population densities (0.20 bobcats/km 2) occurred in Pope and Hardin counties, whereas densities were lowest (0.15 bobcats/km2) in Gallatin and Alexander counties. Finally, I created a spatially-explicit population model to predict population growth and characterize bobcat dispersal behavior as populations increased. Model simulations illustrated: (1) percent change in the proportion of juvenile males in the population to demonstrate how dispersal affected population exchange and (2) rates of void filling vs. tolerance of juvenile males into the population to characterize spatial organization.