Integrating Physical and Ecological Models to Assess Restoration Impacts on Fish, Roseate Spoonbills and American Crocodiles in Northeastern Florida Bay

Jerome J. Lorenz¹, Jon C. Cline², Eric D. Swain³, Donald L. DeAngelis⁴,Valerie L. Chartier⁵, Kevin Chartier⁵, Mike Cherkiss⁵, Leonard Pearlstine⁵ and Frank J. Mazzotti^5
1Audubon of Florida, Tavernier Science Center, Tavernier, FL, USA
²Department of Biology, Case Western Reserve University Cleveland, OH, USA
³USGS Center for Water and Restoration Science, Ft. Lauderdale, FL USA
⁴Department of Biology, University of Miami, Coral Gables, FL, USA
⁵Ft. Lauderdale Research and Education Center, University of Florida, Davie, FL, USA

Water management activities in southern Florida have altered hydrologic conditions throughout the region with declines in wading bird and crocodilian numbers linked to these changes. In particular, the Roseate Spoonbill (Platelea ajaia) and the American Crocodile (Crocodylus acutus) in northeastern Florida Bay exemplify the detrimental effect of water management practices on the Everglades landscape and have been identified as key indicator species for restoration of this estuarine ecosystem. These two species have overlapping nesting ranges, forage in the same habitat, and have similar hydrologic and hydrographic requirements. In addition, both species are dependent on the community of small, demersal fishes as the base of their respective food webs. This fish community has also been demonstrated to respond in a predictable manner to anthropogenic hydrologic and hydrographic changes.

We have developed interactive models that link hydrologic changes to hydrography, prey base production and success of spoonbills and crocodiles. The Southern Inland and Coastal System (SICS) model uses empirical data or SFWMM outputs as boundaries for a numerical model of flow and transport to estimate water levels and salinity in the estuarine areas of the mainland and Florida Bay. Simulation output from SICS model is, in turn, used to drive the ALFISHES Model; an Across Trophic Levels System Simulator (ATLSS) model that predicts responses of functional fish groups in Everglades mangrove zone of Florida Bay. The ALFISHES model is based on analyses of 15 years of systematic fish collections in the mangrove zone. A spoonbill habitat suitability index (HSI) has been developed to model the influence of hydrology on conditions for foraging by spoonbills in mangrove swamps adjacent to northeastern Florida Bay. The model is based on seventy years of spoonbill monitoring that included nesting success and foraging behavior. A habitat suitability model was also developed for the American crocodile to evaluate effects of restoration on this endangered species. The model is based on laboratory experiments and over 20 years of field data and includes components for hatchling survival (fall), crocodile foraging (spring), and nesting (summer). The inputs for these HSI models are derived from SICS and ALFISHES outputs. Model equations, supporting science, and validation and application of these models will be documented in poster presentations. With development of restoration scenario capabilities in the SICS model, linking these complex models in an ecologically meaningful way will prove an effective and powerful tool for evaluating potential impact of water management policies on coastal wetlands.

Contact Information: Jerome J. Lorenz, Audubon of Florida, Tavernier Science Center, 115 Indian Mound Trail, Tavernier, Fl 33070 USA, Phone: 305-852-5092, Fax: 305-852-5318, Email: jlorenz@audubon.org

(This abstract is from the 2006 Greater Everglades Ecosystem Restoration Conference.)

Back to Project Homepage