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Presented at the NABS Annual meeting, Athens, Georgia, 2003
in Wetlands and Lentic Ecology
Spatial and temporal patterns of fish population dynamics in the Florida Everglades
C.R. Ruetz III1, J.C. Trexler2, F. Jordan3, W.F. Loftus4, and S. Perry5. 1Annis Water Resources Institute, Grand Valley State University, Muskegon, Michigan, USA 49441, 2Department of Biological Sciences, Florida International University, Miami, Florida, USA 33199, 3Department of Biological Sciences, Loyola University, New Orleans, Louisiana, USA 70118, 4U.S. Geological Survey, Florida Carribbean Science Center, Everglades National Park Field Station, Homestead, FL, USA 33034, 5Natural Resources Center, Everglades National Park, Homestead, FL, USA 33034
We examined population dynamics of five abundant fishes in the Florida Everglades. Fishes were collected with 1-m2 throw traps at 17 sites five times per year between 1996 and 2001. Our sites were located throughout three water-management units, and sampling events corresponded with important transitional phases of the wet-dry season. We found significant patterns in fish density across space and time for all species. Variation in fish density among sites within water-management units was greater than among water-management units, and intra-annual variation was greater than among years for most species. These patterns in fish density were affected by local hydrology. We found significant relationships between fish density and time since the most recent drought, although the strength of these relationships varied among sites. Heterandria formosa, Lucania goodei, Fundulus chrysotus, and Jordanella floridae were most strongly affected by drought, whereas the response of Gambusia holbrooki was weak and variable. Densities of Heterandria formosa, Lucania goodei, and Fundulus chrysotus usually increased gradually following a drought. In contrast, Jordanella floridae recovered quickly following a dry-down event and then their densities usually declined. Our results suggest that local hydrology is an important factor shaping patterns of fish population dynamics across the Everglades landscape.
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