Rapid response of fish and aquatic habitat to removal of a tidal barrier

Abstract River barrier removal is used increasingly as a conservation tool to restore lotic habitat and river connectivity, but evidence of its efficacy is incomplete. This study used a before–after methodology to determine the effects of removing a tidal‐limit barrier on the fishes, macroinvertebrates, and habitats of an English coastal stream. Following barrier removal, habitat diversity increased immediately upstream and remained similar downstream. Mobilized silt altered the substrate composition immediately downstream, but this was temporary as silt was flushed out the following winter. Changes to macroinvertebrate communities occurred upstream and downstream of the former barrier but these were transient. A dramatic and sustained increase in fish density occurred immediately upstream of the barrier after its removal, but effects downstream were…