Influence of temperature on surface sediment disturbance by freshwater fish: a microcosm experiment

Water temperature is a key parameter that regulates activities of ectotherms (e.g., fish) and has been projected to rise in the future in the context of climate change. Surface sediment disturbance (SSD) is an important function performed by fish that modifies benthic habitat properties and may thus influence ecosystem functioning. However, the link between SSD by fish and temperature remains unexplored. In this study, we experimentally assessed the influence of two contrasted temperatures (10 versus 20°C) on SSD by three freshwater fish species in aquaria. After 10 days, the total surface disturbed by the species was approximately 2–3 times higher at warm than at cold temperature but the number and area of patches disturbed by the species were not significantly different. The stone loach Barbatula barbatula, a benthic fish species, had a higher SSD activity (i.e., total surface disturbed, number and size of patches disturbed) both at cold and warm temperatures than two cyprinid species, chub Squalius cephalus and sofie Parachondrostoma toxostoma. On average, SSD by B. barbatula resulted in approximately two and three more patches than the cyprinid species at 10 and 20°C, respectively, and the mean patch area disturbed by B. barbatula was about two times larger than the ones disturbed by the cyprinid species. The total surface disturbed by the cyprinids at warm temperature was roughly equivalent to the surface disturbed by B. barbatula at cold temperature. Our results thus suggest that SSD by fish could increase in future warmed conditions.We experimentally assessed the influence of two contrasted temperatures on surface sediment disturbance (SSD) by three freshwater fish species SSD was 2-3 times higher at 20°C than at 10°C for the three species The stone loach had a higher SSD activity than the two cyprinid species Our results suggest that SSD by fish could increase in future warmed conditions