Meeting Abstract
1.5 Saturday, Jan. 4 09:00 Variation in thermal sensitivity of sprint speed, thermal behavior and evaporative water loss MILES, D.B.; Ohio University urosaurus@gmail.com
Recent studies have highlighted the susceptibility of ectotherms to altered thermal niches arising through climate warming. Determining the projected responses of a species to climate warming requires data on the thermal tolerance of a species, variation in body temperature, preferred temperature and sensitivity of physiological performance to temperature. I estimated CTmin, CTmax, Tpref, and the thermal performance curve for sprint speed for two populations of Urosaurus ornatus that differed in substrate preferences and elevation. I sampled lizards at Saguaro National Park, AZ (elev. 870m) and Sevilleta National Wildlife Refuge, NM (elev. 1780). I also deployed dataloggers to characterize the operative thermal environment at each location. The thermal landscape was warmer at the low elevation site with temperatures exceeding CTmax between 2 – 6 hr per day during the summer. Te rarely exceeded CTmax at Sevilleta. Despite a difference in the thermal environment lizard populations exhibited similar values for CTmin and CTmax. However, I observed a 1°C shift in Tpref for the Saguaro population between 1998 and 2013. The shape of the performance curves were generally similar, but lizards from Saguaro had faster speeds at warmer temperatures. These results suggest that U. ornatus may be buffered from climate warming. However additional data from other populations at other elevations and latitudes are necessary for ascertaining the potential to adapt to a warmer environment.
