Meeting Abstract
102.1 Tuesday, Jan. 7 08:00 Avoiding Errors When Measuring Operative Temperature BAKKEN, G.S.*; KROCHMAL, A.R.; ANGILLETTA, M.J.; Indiana State University; Washington College; Arizona State University george.bakken@indstate.edu
Climate change may increase average air temperatures by 2 – 4° C by 2100. To predict the resulting shifts in life histories and species’ ranges, we need to reliably measure microclimates with precision better than the expected change due to global warming, particularly at margins of distributions. These microclimates include wind and radiation, which change independently of air temperature. Operative temperature (Te ) is a useful integrated thermal parameter that combines air temperature and radiative heating as modified by wind. In principle, Te can be measured directly using physical models as Te thermometers. These models explore the environment at the spatial scale of the animal and are relatively inexpensive to produce in large numbers. Although many studies consider anatomical details as unimportant and use simple cylindrical sensors or TidBits® , these can yield errors in Te estimation ranging from 2 – 14° C. While random error decreases as sampling increases, poorly designed Te thermometers create systematic errors that might be confounded with climate change. Model validation is thus essential. We demonstrate the importance of anatomical details by comparing temperatures of Eastern painted turtles against those of simple and detailed Te thermometers. As tethering animals for such comparisons poses risks of heat stress, we developed an alternative approach where predicted and measured body temperatures of freely moving animals were compared for a simple habitat. This approach detects unanticipated effects of movement and tests the ability to predict body temperature from operative temperature.
