Adaptive Physiology at a local scale, and implications for species distribution models under climate change scenarios.

Abstract

In heterogeneous environments, individuals experience different combinations of physical and biological pressures over small spatial scales. For many marine organisms with limited adult mobility, but planktonic dispersal, localised adaptation may occur over an organism's life cycle through acclimation. Understanding the plasticity of physiology through acclimation is vital in predicting species' vulnerability to climate change. In this study we assessed local conditions on four sections (<500 m apart) of a tropical rocky shore to determine whether differences in local conditions affect the physiology of the limpet, Cellana grata. Shore sections differed in aspect, exposure and topography, and in biological characteristics such as levels of competition (grazer density) and facilitation (barnacle cover). Using a bootstrapped principal component analysis, we demonstrated that sections of shore differed significantly in terms of the relative contributions of the multiple variables measured. As a measure of physiological acclimation, detachment temperatures of limpets from each site were measured in the laboratory and higher detachment temperatures were found in limpets from shore sections with greater physical stress and lower biological stress. These results demonstrate that physiological limits can acclimate to local conditions over short temporal scales and uniform physiology should not be assumed in species distribution or climate change models.