Spatial Ecology of Gila Monsters in a Subsidized Resource Environment

Pierson, Matt Department of Biology Center of Excellence for Field Biology Austin Peay State University Clarksville, Tennessee USA

mpierson@my.apsu.edu

DeNardo, Dale F.

School of Life Sciences Arizona State University Tempe, Arizona USA

Gallardo, Leticia Biology Department West Valley College Saratoga, California USA

Parker, Mickey Department of Wildlife and Fisheries Sciences Texas A&M University College Station, Texas USA

Animal movements and space use are often conceptualized using the home range concept. Home ranges are determined by temporal, spatial, and individual-level processes. Within the environment, one of the key factors influencing space use is the distribution of resources. Alterations to resource distribution and availability can have profound consequences on spatial habitat use. We analyzed spatial data collected from Gila Monsters (Heloderma suspectum) in a subsidized resource environment (golf course) and a non-subsidized (natural) environment. We calculated kernel density polygons and minimum convex polygons for estimates of space use. After adjusting area estimates for sex, number of fixes, and year, males in the subsidized environment had an average overall area of 13.6 ha while the females had an area of 8.3 ha. In the unsubsidized environment, males had an average overall area of 43.2 ha while females had an area of 23.6 ha. Gila Monsters between the two environments also exhibited seasonal differences, primarily in the dry and monsoon seasons. This suggests that home ranges of Gila Monsters may be smaller in subsidized resource environments than those of un-subsidized environments due to increases in available resources.