Contact networks reveal potential for interspecific interactions of sympatric wild felids driven by space use. Issue 3 (2nd March 2017) - Lewis, Jesse S.
Abstract: Competitive interactions between species are fundamental to understanding species assemblages, community dynamics, and ecological processes. Anthropogenic landscape change, particularly resulting from urbanization, can alter interspecific interactions; however, different forms of urbanization are predicted to have contrasting effects on competitive interactions. We developed contact networks between bobcats and pumas to evaluate (1) the potential for interspecific interactions between wild felids and (2) how space‐use metrics might change along the urban gradient, including low‐density exurban development, wildland–urban interface, and wildland habitat, at both the population and individual level. We used an extensive telemetry data set for bobcats and pumas across multiple study areas to evaluate four space‐use metrics: space‐use overlap (used to define potential interactions among animals) and three additional contact network metrics, including degree (the number of potentially interacting animals), in‐strength (sum of space‐use overlap for animals), and equivalent social connectivity (ESC; considering both space‐use extent and the amount of space‐use overlap). Space‐use extent was an important predictor of potential social interactions as measured by space‐use metrics. Bobcats appeared to have a greater opportunity to interact with female pumas based on space‐use overlap, degree, and in‐strength, which demonstrates that relative scale of space‐use extent among animals could be important for understanding interactions; ESC, however, was greater between bobcats and male pumas, likely due to the larger space‐use extent by male compared to female pumas and the positive relationship between space‐use extent and ESC. In addition, pumas and male bobcats exhibited a greater opportunity to interact, based on space‐use overlap, degree, and in‐strength, and demonstrated higher ESC compared to female bobcats. Counter to our predictions, felids associated with urbanized grids or with greater amounts of urbanization in their extent of space use did not appear to exhibit greater values of space‐use metrics compared to animals with less exposure to urbanization; these results appear consistent with previous research evaluating population characteristics of felids across broad scales in our study areas. Greater ESC for male pumas and male bobcats suggests that males could be particularly important for facilitating connectivity of some ecological processes, such as the transmission of disease, through interspecific contact networks.