Project Summary Sheet

Project: Parameter Estimation and Population-Based Simulation Modeling of American Alligator Populations in Support of ATLSS

Web Sites: www.fcsc.usgs.gov (see http://cars.er.usgs.gov/), sofia.usgs.gov, www.atlss.org

Location (Subregion & County): Central and southern Everglades.

Funding (Source): Critical Ecosystem Studies Initiative (CESI), USGS Place-Based Studies

Principal Investigator(s): Kenneth G. Rice, USGS - Biological Resources Division: ken_g_rice@usgs.gov; H. Franklin Percival, USGS - Florida Cooperative Fish and Wildlife Research Unit; Daniel Slone, US Forest Service

Project Personnel: Chris Gregory (MS student, UF)

Supporting Organizations: University of Florida, USFWS, NPS, USFS, FFWCC

Associated / Linked Projects: Component of the ATLSS Program

Overview & Status: Despite its prominence biologically and publicly in the system, many important questions about basic population parameters and strategies of alligators remain unanswered. In order to adequately understand alligator populations to model population growth, existing data must be assembled and new data collected for many parameters. A simulation model can then be constructed and validated both with existing data and through expert opinion. The ATLSS (Across Trophic Level System Simulation) project requires an alligator population model to simulate the south Florida ecosystem under varying management strategies. This project provides estimation of population parameters and modeling frameworks for this simulation process. Currently, we have established the American Alligator Production Index within ATLSS and have an initial working Alligator Population Model under review.

Needs & Products: The Production Index is now available for use in the restoration process but is also undergoing further calibration, validation, and updating with new data. The population model has been completed and is beginning initial expert review, calibration, and validation. Both models will be fully functional and available for use by summer 2002.

Application to Everglades Restoration: (1) This study encompasses 2 of the critical projects for restoration of crocodilian populations determined by a meeting of over 40 biologists, managers, and administrators held in Homestead in December, 1998. (2) This study directly addresses the critical ecological pathways outlined in the Everglades Ridge & Slough Conceptual Ecosystem Model. (3) This study provides an ecological study tool and population model deemed critical in the Federal Objectives for the South Florida Restoration by the Science Sub-Group of the South Florida Management and Coordination Working Group. (4) This study addresses critical information needs such as restore ecosystem structure and function, recover populations of selected indicator species, and identification of ecological assessment indicators identified in South Florida Ecosystem Restoration: Scientific Information Needs by the Science Subgroup of the South Florida Ecosystem Restoration Task Force. (5) We investigate the decline in numbers and shift in distribution of the American alligator identified as an Everglades National Park major issue and information need in South Florida Ecosystem Restoration: Scientific Information Needs by the Science Subgroup of the South Florida Ecosystem Restoration Task Force.