EAT, PREY, LIVE: THERMAL ECOLOGY AND ENERGY REQUIREMENTS OF COASTAL AND INLAND POPULATIONS OF PACIFIC RATTLESNAKES (CROTALUS OREGANUS).
Hayley L. Crowell; California Polytechnic State University; 1 Grand Ave., San Luis Obispo, CA, 93407; (301) 693-3414; hlcrowel@calpoly.edu; Emily N. Taylor
Understanding the effects of changing temperatures on ectothermic species is crucial if land managers and researchers are to make informed decisions about how to mitigate the predicted loss of diversity as a result of anthropogenic climate change. We used field-active body temperature data from free-ranging snakes to calculate field metabolic rates and average annual energy expenditure of 4 populations (2 inland and 2 coastal) of Pacific rattlesnakes (Crotalus oreganus) on the Central Coast of California. Snake body temperature data were collected via internal implantation of Thermochron iButton temperature loggers from 2006 to 2017 during the snakes' active season (April-Oct). Despite dramatically different ambient temperatures at the field sites, snakes at inland and coastal sites thermoregulate such that they experience similar mean daily body temperatures. However, inland snakes are significantly larger in mass than their coastal counterparts and therefore have higher overall metabolic rates and energetic requirements. Operative temperature models were used throughout each of the four field sites in order to characterize microhabitat temperatures available and calculate thermal quality of the landscape. In combination with predicted increases in ambient temperature, probable changes in body temperatures, activity times, and energy requirements were extrapolated for each site through the year 2100.
Ecology and Conservation of Amphibians and Reptiles III   Student Paper