| Session IV: Wetlands |
Abstract #: 97405 |
ARE TREE ISLANDS IN LOXAHATCHEE NATIONAL WILDLIFE REFUGE SMALL AND CIRCULAR OR LARGE AND ELONGATED AND ORIENTED IN THE DIRECTION OF FLOW?
Laura A. Brandt and Wiley M. Kitchens
University of Florida, Department of Wildlife Ecology and Conservation and USGS-BRD, Florida Cooperative Fish and Wildlife Research Unit, Gainesville, Florida
ABSTRACT
Historic descriptions of tree islands in the Everglades have characterized them as being small and circular or large and elongated and oriented in the direction of historic water flow. In this study we examine that notion for one area of the Everglades, Loxahatchee National Wildlife Refuge. Size, shape, and orientation were determined for 2144 tree islands identified from 1987 satellite imagery. Tree islands ranged in size from 0.05 ha to 62 ha and represented a continuum of sizes. All circular tree islands were < 0.6 ha while elliptical tree islands ranged in size from 0.05 ha to 62 ha. Orientation of elliptical tree islands was bimodal with most oriented between 0 and 20 degrees or 150 and 180 degrees (180 = north to south). Larger tree islands showed less variance in orientation than smaller tree islands. Orientation was not correlated with flow direction predicted from elevation data alone, but appears to be more related to the large scale north to south gradient and historic patterns of sheet flow. Laura A. Brandt and Wiley M. Kitchens University of Florida, Department of Wildlife Ecology and Conservation and USGS-BRD, Florida Cooperative Fish and Wildlife Research Unit, Gainesville, Florida.
