Aquatic refugia are integral features of the south Florida landscape and are a critical component of the relationships between aquatic fauna, wading birds, alligators and their prey base.
Refugia may be defined as specific locations where a species or suite of species persist for short periods of time when parts of their preferred habitats become uninhabitable because of temporal changes in climatic or ecological conditions (e.g. drought). The ecology of aquatic refugia in south Florida is not well understood.
Aquatic refugia within the Southwest Florida landscape are spatially limited and temporally significant habitats that exist along a continuum, from natural depressions in the landscape to man-made canals and ponds. These features are particularly important to wetland dependent species during the dry season as availability of habitat shrinks with receding water levels.
Drainage of large areas has drastically altered the biotic production potential of aquatic habitats in Southwest Florida, not only by reducing the surface area and volume of water available, but also by interrupting the aquatic pathways between refugia and the surrounding seasonal wetland communities. The purpose of the present study was to determine the importance of sites in the Southwest Florida landscape that function as aquatic refugia for communities of wetland dependent organisms, with special emphasis on the function of these communities as they relate to the survival and perpetuation of threatened and endangered species.
Five types of refugia were selected for the study: man-made canals, man-made “artificial” ponds, natural willow and popash ponds, and tram ditches. Tram ditches are depressions left from the construction of logging tram roads created more than half a century ago.
The study revealed the vital importance of the refugia sites, and the vital role alligators play in maintaining these water-filled oasis areas during the dry season.