projects > across trophic level system simulation (atlss) - wading birds
Across Trophic Level System Simulation (ATLSS) - Wading Birds
Through the 1960's, the Everglades served as a major breeding center for wading birds in the eastern United States. Over the past several decades, wading bird reproduction has declined dramatically, although the area is still an important feeding ground (Robertson and Frederick 1994). Numerous theories have been offered to explain the decline, including reduction in extent of habitat, reduced prey availability, alteration of drying rates, loss of peripheral short-hydroperiod wetlands, increase in frequency of drydowns, mercury toxicity, effects of eutrophication, shifts in migratory patterns, and changes in storm frequency (summarized in Fleming, Wolff, and DeAngelis 1994).
The ATLSS Wading Bird Foraging Conditions Index Model uses knowledge of how hydrologic factors affect the concentration and availability of food resources during the breeding season to compute a Foraging Conditions Index (FCI) for wading birds. The FCI is a composite index of spatial and temporal patterns. We express the effects of proposed hydrologic scenarios as changes in the spatial pattern of foraging potential over the model area for the 31-year simulation period.