Fish dispersal in a seasonal wetland: influence of anthropogenic structures

Abstract

Knowledge of fish dispersal routes when exploiting temporary habitat is important for understanding the ecology of species and for designing and conducting conservation and land-management activities. We evaluated fish dispersal in a network of seasonal habitats and a permanent fish source (a lake) in a subtropical wetland, in Florida, sampled biweekly from May 2002 to May 2003. Fish dispersal routes were influenced by (1) local physical conditions, (2) anthropogenic alterations and (3) fish species and size. Fish from the source dispersed into 9 of the 25 seasonal sites evaluated, via temporarily formed dispersal corridors between the source and the sites. Low connection depths along the corridors were a key factor, allowing small-bodied species (e.g. Gambusia holbrooki, Elassoma evergladei) to travel farther than large-bodied fish (e.g. Erimyzon sucetta, Lepomis macrochirus). Fish travelled distances of 0.7–4 km. Anthropogenic structures both enhanced (ditches, sand roads) and blocked (a railroad, soil dumps) fish dispersal routes. We demonstrated extensive opportunistic use by fish of seasonal wetlands. Our results indicated that anthropogenic alterations to the landscape can provide habitat for native fish and also allow dispersal of non-native fish and thus should be implemented with care.