Temperature-based activity estimation accurately predicts surface activity, but not microhabitat use, in the Endangered heliothermic lizard Gambelia sila

—With the existence of many endangered terrestrial ectotherms now being threatened in the face of climate change, effective tools to aid in the management of their conservation are necessary. Temperature-based activity estimation (TBAE) is an automated method for predicting surface activity and microhabitat use based on the temperature of an organism and its habitat, and TBAE may be used to reduce the monitoring effort for sensitive species. However, its efficacy has not been assessed in heliothermic species. We hypothesized that heliothermy would facilitate the accurate prediction of surface activity due to the rapid changes in temperature effected by exposure to solar radiation, but that TBAE would not accurately predict microhabitat use because heliothermic lizards shuttle too frequently among microhabitats. In this study, we assessed how well ambient air temperature and lizard physical model temperature predicted surface activity and microhabitat use of a federally-listed Endangered lizard, Blunt-nosed Leopard Lizard, Gambelia sila, by comparing these variables to continuously logged active lizard body temperatures in the field. While surface activity was correctly predicted 93% of the time using either ambient or physical model temperatures, the accuracy in predicting microhabitat use only ranged from 47–72%. Finally, TBAE allowed us to predict the time of morning emergence from burrows to within approximately 11 minutes. TBAE is a promising means for remotely monitoring surface activity and morning emergence of heliotherms, however its utility in distinguishing microhabitat use in heliotherms is limited.