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Project Summary Sheet

U.S. Geological Survey, Greater Everglades Science Program: Place-Based Studies Initiative

Fiscal Year 2003 Project Summary Report

Project: Everglades Crayfish (Procambarus spp.) Response to Hydrologic Restoration of the Florida Everglades

Project Start Date: 2000 Project end date: 01/09/2003

Web Sites: ATLSS.ORG

Location: The Greater Everglades ecosystem

Funding Source: Critical Ecosystems Studies Initiative

Principal Investigator: Dr. Ray Hilborn, School of Fisheries, University of Washington, Seattle, Washington Phone: 206-543-3587, Fax: 206-685-7471

Project Personnel: Donald L. DeAngelis, Phone: 305-284-1690 e-mail:

Other Supporting Organizations: USGS/BRD, NPS

Associated Projects: Component of ATLSS Program

Overview & Status: The purpose of this project is to examine how crayfish species respond to proposed hydrologic management in the Florida Everglades. This project will construct a spatially explicit, stage-structured population model for two species of procambarid crayfishes, the Everglades crayfish (Procambarus alleni) and the slough crayfish (P. fallax), building on up to 18 years of crayfish population data available from Drs. Joel Trexler and William Loftus. This model will provide a mechanism to estimate pre-drainage distributions of crayfish by coupling it to the natural systems model. Moreover, alternative hydrologic management scenarios may be compared to each other and with pre-drainage crayfish model outputs to evaluate the efficacy of proposed hydromanagement scenarios. Because white ibises (Eudocimus albus) forage primarily on crayfish while nesting, the availability of crayfish has obvious implications for recovering populations of this species. The crayfish model will allow managers to evaluate restoration alternatives, and examine how these alternatives may be compared to pre-drainage estimates of crayfish community composition.

Needs & Products: This project addresses how hydrologic restoration of the Everglades will affect the distribution of two species of crayfishes. The slough crayfish dominates the species composition in those locations that have been flooded continuously for more than two years, while the Everglades crayfish dominates in those locations that dry annually. Ibis nesting success is positively related to severity of spring drydown, crayfish content in diet, and reduced foraging distance. Hydrology may affect foraging opportunities directly through the depth of water in which ibis can feed or indirectly by influencing the density of prey. Model construction is now essentially finished and will be reported on in a Ph. D. dissertation, to be defended in July 2003. Incorporation into the ATLSS Program will begin soon after the Ph. D. defense. The crayfish model takes site-specific observations and utilizes environmental drivers (hydrology) to produce estimates of crayfish abundance and population persistence on the Everglades landscape. A GIS-based species index has been developed and turned over to ATLSS. The functional model will be submitted and a method for incorporating it into the ATLSS Program. Additionally, a summary report will be constructed. This report will contain a full description of the data and methods used to develop the model. It will also contain an instruction manual for use of the model. The model will produce GIS output.

Application to Everglades Restoration: The model will provide expected responses by crayfish to restoration alternatives including CurrentBase 1995, FutureBase2050, and AltD13R. The crayfish model will be incorporated into the suite of ATLSS models, particularly as a prey resource for white ibis.

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