A Habitat-Based Metapopulation Model of the California Gnatcatcher

Type: journal article

Article abstract: We present an analysis of the metapopulation dynamics of the federally threatened coastal California Gnatcatcher (Polioptila c. californica) for an approximately 850 km2 region of Orange County, California. We developed and validated a habitat suitability model for this species using data on topography, vegetation, and locations of gnatcatcher pair observations. Using this habitat model, we calculated the spatial structure of the metapopulation, including size and location of habitat patches and distances among them. We used data based on field studies to estimate parameters such as survival, fecundity, dispersal, and catastrophes, and combined these parameters with the spatial structure to build a stage-structured, stochastic, spatially-explicit metapopulation model. The model predicted a fast decline and high risk of population extinction with most combinations of parameters. Results were most sensitive to density-dependent effects, the probability of weather-related catastrophes, adult survival, and adult fecundity. Based on data used in the model, the greatest difference in results was given when the simulation;s time horizon was only a few decades, suggesting that modeling based on longer or shorter time horizons may underestimate the effects of alternative management actions.

Number of pages: 13

Authors: Akcakaya, H. Resit; Atwood, Jonathan;

Journal title: Conservation Biology

Month: April

Year: 1997

Volume: 11

Number: 2

Keywords: California gnatcatcher; conservation biology; NCCP; threatened and endangered species;

Species: Coastal California gnatcatcher

Vegetation communities: coastal sage scrub

Download document
Please contact us to request access to this file.