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cape sable seaside sparrows >
project summary
U.S Geological Survey, South Florida Ecosystem Program: Place Based Studies
Web Site: ATLSS.ORG
Location: The total system
Principal Investigator: M. Philip Nott, The Institute for Bird Populations, Point Reyes Station, CA 94956, Phone: 415-663-2050, e-mail: pnott@birdpop.org
Project Personnel: Don DeAngelis, Phone: 305-284-1690, e-mail: don_deangelis@usgs.gov
Other Supporting Organizations: USGS/BRD, NPS, USACE, EPA
Associated Projects: Component of ATLSS Program
Overview & Status: Recent surveys of the Cape Sable seaside estimate its population size at fewer than 6000, and its range to be restricted to the extreme southern portion of the Florida peninsula, almost entirely within the boundaries of the ENP and Big Cypress National Preserve. Declines have occurred in the sparrow population across its entire range, probably due to higher water levels in recent years (Nott et al. 1998). Because the current range of the sparrow is limited to a few hundred km2 and because it is subject to flooding and fires, the population is highly vulnerable. Changes to the hydrology of the southern Everglades, planned as part of the Comprehensive Ecosystem Restoration Plan, could increase the water levels in parts of the sparrow's range and inadvertently increase the risk to the reproductive success. It is critical to predict not only how serious these risks are but which areas they most affect. During the first two years of this study two related models for the Cape Sable seaside sparrow were developed: 1) a spatially-explicit species index (SESI) model that indexes the breeding potential of suitable habitat as the potential number of offspring that could be produced in a given year, given the hydrologic pattern influencing a given area; and, 2) a spatially explicit individual based population model, SIMSPAR, that simulates a population of Cape Sable sparrows, as a collection of individuals, on the dynamic landscape on daily time steps. The demographic model was subjected to thorough sensitivity analysis for a number of important ecological and life cycle parameters, and validated well when compared against available empirical data on population numbers in the "western" subpopulation. There is strong agreement between model "hind-casts" and the observed rapid decline since 1993. Analysis of ongoing field data provides refined values of model parameters.
Needs & Products: This project provides insight into the most important issues regarding the effects of hydrologic and vegetation change on this federally endangered species: hydrologic restoration effects on the persistence of cape sable seaside sparrow populations; habitat modification and management strategies for enhancing and restoring decimated populations. The models assess the relative restorative effects of proposed hydrologic regimes on the distribution of available sparrow breeding habitat and the corresponding size and distribution of the sparrow populations. Through adopting a spatially-explicit individual based stochastic modeling approach ,this project has identified several highly sensitive life cycle and behavioral parameters. The model species' response to various levels and types of habitat degradation suggests that there is an urgent need to monitor and manage critical areas of the species' geographic range, to both maintain current population levels, and restore the decimated population west of Shark River Slough. A draft website documenting the demographic model can be found at http://www.birdpop.org/simspar/main.html. Application to Everglades Restoration: To date SIMSPAR has been used to assess the following proposed hydrologic scenarios: C&SF Comprehensive Review Study (Restudy); Alternatives 1-6 and 13D - October 1997 through July 1998; Experimental Water Deliveries Program, Modified Water Deliveries Project, and C-111 Project (ModWater) - January 1999; ModWater - July 1999. both the breeding potential index model and the population demographic model have been used in evaluating water regulation scenarios for the Central and South Florida Project Comprehensive Review Study.
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| U.S. Department of the Interior, U.S. Geological Survey, Center for Coastal Geology This page is: http://sofia.usgs.gov /projects/summary_sheets/sparrowsum.html Comments and suggestions? Contact: Heather Henkel - Webmaster Last updated: 04 April, 2003 @ 09:22 AM (KP) |
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