Meeting Abstract

21.2  Wednesday, Jan. 4  Biophysical modeling of foraging behavior: climate change may limit foraging LEVY, O.*; DAYAN, T.; PORTER, W. P.; KRONFELD-SCHOR, N.; Tel Aviv University; Tel Aviv University; University of Wisconsin, Madison; Tel Aviv University

The effect of climate change on activity patterns of animals and thus on the structure of ecological communities is almost unstudied. We studied field foraging behavior of diurnal rocky desert golden spiny mice (Acomys russatus), and developed a two-stage statistical model to describe how biotic and abiotic conditions affect this behavior. In the first stage of foraging the mouse decides whether to forage in a certain microhabitat, and in the second stage, after it has entered a microhabitat, it decides how long to stay in it. A biophysical model, Niche MapperTM ,suggests that spiny mouse foraging behavior is constrained by energy expenditure (EE) and evaporative water loss (EWL): (1) the chances of foraging decrease as EE increases and (2) during summer ambient temperatures (Ta) increased to a range where mice needed to evaporate water to prevent hyperthermia. Foraging behavior at both stages of foraging declined sharply when Ta was higher than 41°C during summer in the non-shaded, between-boulder (BB), microhabitat, and the predicted EWL rate increased to 0.2 [mg H2O/s*gram]. Under RegCM future climate scenarios for 2100, maximum Ta in the study area will increase by 5.2°C and 3.6°C in A2 and B2 scenarios respectively; our statistical model shows a reduction in the number of hours suitable for foraging in the BB microhabitat from 10 hours under current conditions to 7 and 9 hours in A2 and B2 scenarios, respectively. Consequently, mice may be forced to concentrate their summer foraging in the more sheltered microhabitats, where vipers pose a predation risk in summer. Moreover, mice can be expected to shift their activity towards morning and evening. This reduction in the spatial and temporal niche may increase intraspecific competition.