Movement Responses of Stream Fishes to Introduced Corridors of Complex Cover

Although the efficacy and design of terrestrial movement corridors have received considerable attention, the potential role of corridors in connecting stream habitats has not. We studied the movements of three benthic species of fish, fantail darters Etheostoma flabellare, riverweed darters E. podostemone, and Roanoke darters Percina roanoka, among suitable mesohabitat patches (i.e., riffles) through adjacent, less suitable pools in the South Fork Roanoke River, Virginia. We constructed movement corridors of overhead cover in four pools and compared rates of movement through these pools with those through four control pools without corridors. Movement rates were significantly greater through pools with corridors than through control pools for riverweed and Roanoke darters but equivalent through connected and unconnected pools for fantail darters. Interspecific differences in microhabitat use may have been responsible for the observed variability in corridor effects. Our results suggest that intact movement corridors can enhance the persistence of stream fish populations by connecting patchily distributed favorable habitats but that the characteristics of functional corridors may vary, even between closely related species.