WETHEY, DS*; GILMAN, SE; HELMUTH, BS; HILBISH, TJ; Univ of South Carolina, Columbia; Univ of Washington, Friday Harbor; Univ of South Carolina, Columbia; Univ of South Carolina, Columbia: Ecological hindcasting of biogeographic responses to climate change in intertidal ecosystems

Intertidal organisms are often assumed to live close to their thermal limits, and have emerged as potential early indicators of the effects of climate change on natural ecosystems. We have developed mechanistic simulation models for body temperatures of intertidal mussels and barnacles, using climate data from local weather stations and weather satellites, in conjunction with tide predictions and satellite-derived solar radiation. The models of body temperature are typically accurate to within 2�C of temperatures measured with biomimetic temperature loggers. Simulations were carried out on continental geographic scales, in order to examine the climatic influences on current biogeographic limits of intertidal species. We also used 1960s climate records to hindcast past thermal environments near historical geographic limits. Results indicate changes in geographic limits of some species since the 1960s are due to intolerance of climatic conditions.