Spatially-Explicit Species Index Models in Application to Everglades Restoration

By: E. Jane Comiskey and Louis J. Gross

The ATLSS (Across Trophic Level System Simulation) hierarchy of models is designed to utilize varying levels of detail and data availability to assess the relative impact of alternative hydrological plans on the biotic components of South Florida. ATLSS is being used regularly in the ongoing planning for Everglades restoration (see http://atlss.org/). A key segment of the ATLSS hierarchy includes models that make use of information on breeding and foraging requirements for species and how these relate to localized habitat conditions and within-year dynamics of hydrology. These Spatially-Explicit Species Index (SESI) models compare the relative potential for breeding and/or foraging across the landscape without tracking in detail the population dynamics or behavior of individuals for these species. SESI models are viewed as approximations, which are useful in coarse evaluations of scenarios and are an aid in interpreting more detailed ATLSS models.

We describe the general construction and application of SESI models for the Cape Sable Seaside Sparrow, the Snail Kite, Short- and Long-Legged Wading Birds, White-tailed Deer, and Alligators. These models have been applied on a regular basis during the Central and South Florida Comprehensive Restudy to assess the relative effects of alternative scenarios compared to various the base scenarios. The SESI approach offers advantages over Habitat Suitability Index (HSI) methods as it can incorporate both static and dynamic landscape features.