SIMPDEL: A Spatially Explicit Individual-based Simulation Model for Florida Panther and White-tailed Deer in the Everglades and Big Cypress Landscapes. E. J. Comiskey, L. J. Gross and M. A. Huston The Institute for Environmental Modeling University of Tennessee, Knoxville, TN 37996-1610 A model has been constructed with the primary objective of accessing the relative impacts of alternative hydrologic scenarios over the next several decades on the spatial and temporal distribution of panther and deer across South Florida. This includes the capability to produce relative comparisons of mortality, reproduction, individual movement patterns and territory size across the landscape for both species. The modeling approach is individual-based, in which detailed physiological and behavioral information on deer and panther are utilized to construct rules which allow the simulation of over 30,000 individual animals across the landscape, keeping track of individual characteristics such as weight, sex, mating status, and health. The behavioral rules are coupled to a dynamic spatially-explicit hydrologic model, a vegetation model, and a variety of GIS-type inputs for roads, landuse, and feral hog density. The model operates on a daily time step, although within this time step, deer and panther movements are simulated, taking account of local water conditions, forage and prey availability. Spatially, the model makes use of vegetation data to calculate forage availability on a 100 m scale, but tracks deer and panther locations on the daily time step at 500 m scale. Validation involves detailed comparisons of deer distributions with historical data, comparison of aggregated variables such as age-dependent mortality, age-structure, body weight distribution and birth rates with available data, and comparison of model individual-movement patterns with radio collar data. A visualization program has been written to allow easy access to the radio collar information available, and provide a means to readily compare this to model output.