Ecological and evolutionary consequences of disturbance in freshwater ecosystems

Abstract

Aim: We outline a general framework for understanding the dimensions of freshwater disturbances, and highlight their consequences covering individual, population, and community-level effects. Main concepts covered: We distinguish between disturbance drivers and disturbance impacts in a general definition of disturbance, and emphasize the roles of resistance and resilience in determining disturbance impacts. We highlight influences on individuals, life histories and populations, and illustrate how they are dominated by a trade-off between growth and development versus disturbance mortality risk, and the effects of disturbance predictability on solving that trade-off. The difference between refuges, which are important for population recovery on ecological timescales, is distinguished from evolutionary refugia, which are important over much longer time scales (i.e., millennia). The profound influences of freshwater disturbances on the species richness and traits of freshwater communities are described, including their links to disturbance-impacts on the food resources of consumers. When considering community assembly, we outline how species sorting mechanisms may be particularly important following disturbance, whereas disturbance predictability is linked to the turnover of species between habitats. Finally, in examining influences on food webs, disturbance, by altering the composition of consumers, adjusts bottom-up energy flow to predators, the potential for top-down control in food webs, and the length of food chains. Conclusion/outlook: We suggest climate change will alter the predictability, magnitude and other disturbance dimensions, necessitating predictive approaches for management of disturbance impacts. We also highlight the need to better understand the role of freshwater disturbance in managing vulnerable ecosystems, invaders, and restoration.