VALIDATING IBUTTONS FOR CHARACTERIZING SUMMER NIGHTTIME MICROHABITAT USE IN DESERT TORTOISES ACROSS LIFE STAGES

Katelyn N Rock; San Diego Zoo Wildlife Alliance; karock@sdzwa.org; Thomas A. Radzio, Talisin T. Hammond, Ronald R. Swaisgood, Melissa J. Merrick

Faced with climatic extremes, desert species may be at increased risk of depleting water and energy reserves in summer, thus, understanding their thermal ecology and microhabitat use is more crucial than ever to predict responses to climate change. Like many species, desert tortoises (Gopherus agassizii) use burrows as refugia from high daytime surface temperatures to avoid overheating and conserve energy and water. However, during summer, nighttime temperatures are lower at the surface than in burrows. Tortoises sometimes overnight at the surface during summer, raising the question of whether night surface use will increase under climate warming, a strategy that could buffer energy reserves but also increase predation risk. Cameras can address this question, but they are limited by tortoise movements among burrows and do not provide temperature information. In August 2023 and 2024, we observed juvenile and adult tortoise activity in the wild using time-lapse cameras and simultaneously recorded tortoise and environmental temperatures using temperature loggers (iButtons) affixed to tortoises and positioned in burrow and surface microhabitats. We will use camera observations to assess whether tortoise and environmental temperature data can be used to accurately predict nighttime microhabitat use in response to climate change across life stages.

Poster Session