Piscivore Responses to Enhancement of the Channelized Kissimmee River, Florida, U.S.A

Evaluation of the success of ecosystem restoration projects requires identification of appropriate ecological metrics. Comparison of reconstructed food webs (or subsets thereof) from restored and non-restored habitats may be a valuable tool to evaluate restoration success because food webs help identify critical predator–prey relationships, keystone species, relative importance of direct and indirect trophic interactions, and other aspects of ecological function. We compared the diets of apex predatory fishes collected from enhanced and non-enhanced portions of the channelized Kissimmee River, Florida, USA to determine whether food web structure responded to experimental hydrologic manipulations. Diets were reconstructed for black crappie (Pomoxis nigromaculatus), bowfin (Amia calva), chain pickerel (Esox niger), Florida gar (Lepisosteus platyrhincus), largemouth bass (Micropterus salmoides), and warmouth (Lepomis gulosus) collected from enhanced and non-enhanced portions of the Kissimmee River. Prey eaten by apex predatory fishes in the enhanced portion of the Kissimmee River were quantitatively and qualitatively different from prey eaten in non-enhanced portions of the river. Predators in the enhanced portion of the river had fewer empty stomachs, more prey items per individual, more prey types per individual, more fish prey per individual, greater overall richness of prey, and a multivariate suite of prey distinct from predators in non-enhanced portions of the river. Results from hydrologic manipulations suggest that large-scale restoration of hydrologic linkages between the main channel and floodplain habitats will positively affect food web structure and ecosystem function in the Kissimmee River.