Sage Sparrow
Viability of Bell's Sage Sparrow Under Altered Fire Regimes: Integrating Landscape, Habitat, and Metapopulation Modeling Approaches
H. Resit Akçakaya, Applied Biomathematics, Setauket,
NY
Janet Franklin, Dept. of Biology, San Diego State University,
CA
Alexandra D. Syphard, Dept. of Geography, San Diego State
University, CA
John R. Stephenson, US Fish & Wildlife Service,
Bend, OR
This study is published in:
Akçakaya, H.R., J. Franklin, A.D. Syphard, J.R. Stephenson. 2005. Viability of Bell's Sage Sparrow (Amphispiza belli ssp belli): altered fire regimes. Ecological Applications 15:521-531.This model used in this study was developed using RAMAS Landscape. The development of the methods used in this study was supported by the U.S. Department of Agriculture.
Summary of the presentation at the 2004 Annual Meeting of the Society for Conservation Biology (Friday, July 30, 4:00 pm):
We modeled the viability of a Bell's Sage Sparrow (Amphispiza belli ssp. belli) metapopulation under different fire regimes in the foothills and mountains of San Diego County, California, USA. Our approach integrates a landscape model, which predicts the vegetation composition and age under three fire regimes, a habitat model, which interprets the resulting landscape in terms of its suitability for the Sage Sparrow, and a metapopulation model, which predicts the viability of the species based on a dynamic spatial structure as determined by the landscape and the habitat models. Bell's Sage Sparrow depends on early successional shrubland (chaparral) habitat, especially when the availability of preferred open coastal subshrub vegetation is limited. The three fire rotation intervals (FRI) used in the landscape model were 'current' (30 y FRI) representing the effect of increased human ignitions, 'natural' (90 y FRI) representing the historic shrubland fire regime at higher elevations without the effect of human ignitions, and 'long' (150 y FRI) representing a hypothetic endpoint of very low fire frequency. The results indicated that the viability of the Sage Sparrow was highest under the 'current' fire regime scenario, slightly lower under the 'natural', and lowest under the 'long' fire regime scenario.