Common Chuckwalla (Sauromalus ater) in an urban preserve: Persistence of a small population and estimation of longevity

Field studies of amphibians and reptiles rarely span more than two or three years necessitating that inferences concerning population biology of many forms are derived from brief snap-shots of their life history. In 2011 we resurveyed one small population of the Common Chuckwalla (Sauromalus ater) in the Lookout Mountain Preserve in the Phoenix Metropolitan region studied intensively during the 1990s. Extending prior work with this low density population, we assessed current population size by direct count and in relation to variation in abundance in previous years. Recaptures separated by 12-16 years confirmed prior short-term studies indicating that S. ater exhibit growth rates of 1-2 mm per year as adults. Moreover, two females, initially captured in 1995, still resided within 20 m of their original capture sites in 2011. Overall, this urbanized population of Sauromalus ater persists in spite of its small size, increases in recreational activity, trail establishment, and heat island effects associated with the Phoenix Metropolitan region.