Data from: A global perspective on the functional responses of stream communities to flow intermittence

The current erosion of biodiversity is a major concern that threatens the
ecological integrity of ecosystems and the ecosystem services they
provide. Due to global change, an increasing proportion of river networks
are drying and changes from perennial to non-perennial flow regimes
represent dramatic ecological shifts with potentially irreversible
alterations of community and ecosystem dynamics. However, there is minimal
understanding of how biological communities respond functionally to
drying. Here, we highlight the taxonomic and functional responses of
aquatic macroinvertebrate communities to flow intermittence across river
networks from three continents, to test predictions from underlying
trait-based conceptual theory. We found a significant breakpoint in the
relationship between taxonomic and functional richness, indicating higher
functional redundancy at sites with flow intermittence higher than 28%.
Multiple strands of evidence, including patterns of alpha and beta
diversity and functional group membership, indicated that functional
redundancy did not compensate for biodiversity loss associated with
increasing intermittence, contrary to received wisdom. A specific set of
functional trait modalities, including small body size, short life span
and high fecundity, were selected with increasing flow intermittence.
These results demonstrate the functional responses of river communities to
drying and suggest that ongoing biodiversity reduction due to global
change in drying river networks is threatening their functional integrity.
These results indicate that such patterns might be common in these
ecosystems, even where drying is considered a predictable disturbance.
This highlights the need for the conservation of natural drying regimes of
intermittent rivers to secure their ecological integrity.