Data from: Recovery and degradation drive changes in the dispersal capacity of stream macroinvertebrate communities

Freshwater ecosystems face significant threats from various anthropogenic pressures, including pollution, habitat loss, invasive species, and climate change. To address these challenges, protective regulations and restoration efforts have been implemented at national and international levels, resulting in overall improvements in freshwater biodiversity. However, population recovery of macroinvertebrates at impacted or restored sites is greatly affected by the life-history traits and the dispersive abilities of species. This study focuses on understanding the complex relationship between the ecological quality of stream habitats and the dispersal capacity of macroinvertebrate communities in Europe. More specifically, we investigate the role of overall dispersal capacity metric, and specific dispersal traits, in shaping community recovery and degradation processes.Using a comprehensive dataset of 1,327 time series on macroinvertebrate communities ranging from 1968 to 2021 across 23 European countries, this research investigates how changes in ecological quality influence the dispersal capacity of these communities. The findings reveal that recovering sites with improving ecological quality tend to have more dispersive macroinvertebrate communities, characterized by species with more dispersive traits (e.g. active aquatic and aerial dispersers, species with frequent propensity to drift, insects with two similar-sized pair of wings or with larger wings). By contrast, degrading sites show a reduction in the proportion of strong dispersers. However, our results showed this response varied extensively among regions, and thus, some communities that have increased their ecological quality have not gained macroinvertebrates with higher dispersal capacity.This study emphasizes the importance of considering dispersal capacity when planning and implementing freshwater ecosystem restoration projects. Management strategies should focus on enhancing landscape connectivity to create accessible “source” areas and refugia for sensitive taxa, especially as climate change reshapes habitat suitability. Additionally, biodiversity initiatives must incorporate adaptive decision-making approaches that account for the site-specific responses of macroinvertebrate communities to changes in ecological quality.<br>