The life cycle of intermittent streams: How do fish communities respond to annual cycles of wetting and drying?

Abstract

Abstract Intermittent streams periodically cease to flow but still support diverse aquatic assemblages. Community dynamics within intermittent streams are likely driven by a wide range of factors, including drying regime, refuge availability, and connectivity with perennial systems. We compared fish community dynamics over the course of a drying and rewetting period to quantify differences in fish community composition and recovery trajectories across a gradient of drying. We predicted that shifts in fish community structure as streams dry and rewet would be similar across streams with similar drying regimes and streams with more severe drying would be less likely to recover when streams rewetted. Seasonal shifts in community composition were variable in streams that retained isolated pools, with similar patterns occurring in streams of similar size. Despite a lack of synchrony in shifts in community composition among sites, fish communities exhibited recovery post‐drying across all drying regimes. The quick recovery of stream fish communities after drying may suggest intermittent streams provide beneficial habitats or resources and highlight the importance of network connectivity to allow community recovery after drying.