Assessing drought-related ecological risk in the Florida Everglades

To determine how habitat structural complexity, which affects prey vulnerability, influences foraging habitat selection by wading birds, a habitat use versus availability study was conducted throughout the Florida Eve glades in 2005 and 2006. Also, an experiment was conducted where structural complexity was manipulated and effect on wading bird foraging efficiency quantified. Among-year differences in habitat selection were found, which corresponded to disparate hydrological conditions. In 2005, a poor hydrological year in terms of the seasonal r cession, wading birds chose foraging sites that had less emergent vegetation, a thicker flocculent layer and higher prey density relative to random sites. In 2006, an optimal hydrological year, wading bird foraging locations we similar to random sites in all aspects. Submerged vegetation did not affect wading bird site selection in either yea The study indicated that hydrological conditions that affect prey density were more important to wading bird foraging success than fine scale variation in habitat characteristics. However, in years of poor hydrology factors that affect prey vulnerability may become increasingly important because the penalty for choosing low quality foraging habitat is greater than in years of more optimal conditions. Elucidating habitat characteristics which create high quality foraging sites will be beneficial in planning wetland restoration projects and gauging future restoration progress. Received 2 October 2009, accepted 18 May 2010.