Diversity mediates the responses of invertebrate density to duration and frequency of rivers' annual drying regime

Predicting the impacts of global change on highly dynamic ecosystems requires a better understanding how communities respond to disturbance duration, frequency and timing. Intermittent rivers ephemeral streams are that recognized as most common fluvial ecosystem globally. The complexity drying process can give rise different annual antecedent hydrological conditions, but their effect aquatic remains unclear. Here, using invertebrates from 33 across flow-intermittence gradient, we assessed (drying duration frequency) recent characteristics (duration last dry period flowing since rewetting) affect density diversity metrics trophic groups while controlling for other key abiotic factors (dissolved oxygen altitude). We characterized invertebrate taxonomy functional traits capture biological features increase vulnerability drying. In addition, structural equation modelling (SEM), evaluated pathways by which directly impact whether indirectly mediates such relationships. show drove reductions in at community level within groups, whereas both had negative influence metrics. Reductions taxonomic richness were linked increased declined response frequency. Filterer, predator shredder exhibited strongest responses Recent minor Our SEM results demonstrated through diversity. underscore importance considering multiple together with interdependence anticipate freshwater ecosystems.