Data from: Physiological effects of interacting native and invasive bivalves under thermal stress

<p>Across many ecosystems in North America and Europe, native freshwater bivalves (Order Unionida) are threatened by fouling and competition for food by the invasive zebra mussel <em>Dreissena polymorpha</em>. In light of climate change, knowledge on the influence of water temperature on these competitive effects is important, yet poorly understood. This study examines the physiological impact of the interaction between <em>D. polymorpha</em> and the native European unionid <em>Anodonta cygnea</em> over a 28-day period in response to water temperatures of 12, 19, and 25 °C by comparing their glycogen, glucose, lipid, and protein concentrations. The laboratory experiment comprised three treatments: (1) fouling of <em>A. cygnea</em> by <em>D. polymorpha</em>, (2) both species present but not fouling; and (3) a control in which <em>A. cygnea</em> and <em>D.</em> <em>polymorpha</em> were placed separately. Increased water temperatures caused physiological stress in <em>D. polymorpha</em> as evident from reduced glycogen, glucose, lipid, and protein concentrations. <em>Dreissena polymorpha</em> benefited from fouling of unionids, as individuals that fouled <em>A. cygnea</em> tended to have increased glycogen, glucose, lipid and protein concentrations. Competitive effects of <em>D. polymorpha</em> over the unionid bivalve species, however, were not intensified by elevated temperatures. Glochidia release, lower infestation intensity, and physiological stress of <em>Dreissena </em>at higher temperatures were likely confounding factors. The results of this study suggest that understanding the physiological consequences of species interactions at changing temperatures can be an important tool to assess future climate change impacts on freshwater bivalves and aquatic community structures.</p>