The management and conservation of anthropogenically altered ecosystems requires an understanding of the linkage between indicator species and the environmental variables that represent high quality habitat. Wading bird species are sensitive to land use changes, chemical contamination, and fluctuating habitat conditions, and thus serve as important indicators of wetland health. We used a spatio-temporal modeling framework with wading bird foraging distributions reflecting hydrologic conditions most important for generating high quality foraging habitat for Great Egret (Ardea alba), White Ibis (Eudocimus albus), and Wood Stork (Mycteria americana) breeding in the Everglades from 1991 through 2009. Each General Linearized Mixed Model is represented as a function of hydrologic parameters. Support among competing models was assessed using an information-theoretic approach.
Results/Conclusions
Hydrological parameters controlling foraging abundance varied by species. Wood Stork abundance was greatest when foraging patches were inundated for more than 300 days and prey were concentrated into shallow (<10 cm) foraging patches. The abundance of foraging White Ibises was highest when water depth was shallow (<10 cm). Great Egret foraging abundance was greatest in relatively deeper water (15 cm) where prey production was higher. These results indicate water-level fluctuations play a key role in generating the high quality foraging habitat that is reportedly necessary to drive large wading bird nesting events. Our models can be used to predict the effects of real-time management practices as well as wetland restoration scenarios on wading bird foraging in order to optimize anthropogenic water needs, while promoting the spatial and temporal abundance of high quality foraging patches.