Spatiotemporal metacommunity structures and beta diversity of macroinvertebrates in stream and lake systems.

Understanding how metacommunity organization is structured in space and time is a long-standing challenge in community ecology. We aimed to explore the spatiotemporal beta diversity of macroinvertebrate metacommunities and their underlying drivers in two contrasting freshwater systems: streams and a lake. We observed that spatial beta diversity was higher than temporal beta diversity in both systems. Generalized dissimilarity modeling and dispersal-niche continuum index analyses suggested that this is probably because (i) environmental filtering was stronger in space than in time at least in streams, and (ii) dispersal was stronger in time than in space. The relative importance of spatial and seasonal drivers on metacommunity structures was notably different between stream and lake systems, as they have fundamentally different spatiotemporal structure of abiotic (i.e. environmental and hydrological) and biotic (i.e. aquatic insect diversities and life strategies) conditions. Our results shed light on spatiotemporal patterns in lake and stream metacommunities and may be useful for the management of freshwater ecosystems undergoing environmental changes. [ABSTRACT FROM AUTHOR]