Modeling the Effects of Fire Severity and Spatial Complexity on Small Mammals in Yosemite National Park, California

Douglas A. Kelt,Susan L. Roberts,Jan W. van Wagtendonk,James A. Lutz,A. Keith Miles

doi:10.4996/fireecology.0402083

Abstract

We evaluated the impact of fire severity and related spatial and vegetative parameters on small mammal populations in 2 yr- to 15 yr-old burns in Yosemite National Park, California, USA. We also developed habitat models that would predict small mammal responses to fires of differing severity. We hypothesized that fire severity would influence the abundances of small mammals through changes in vegetation composition, structure, and spatial habitat complexity. Deer mouse (Peromyscus maniculatus) abundance responded negatively to fire severity, and brush mouse (P boylii) abundance increased with increasing oak tree (Quercus spp.) cover. Chipmunk (Neotamias spp.) abundance was best predicted through a combination of a negative response to oak tree cover and a positive response to spatial habitat complexity. California ground squirrel (Spermophilus beecheyi) abundance increased with increasing spatial habitat complexity. Our results suggest that fire severity, with subsequent changes in vegetation structure and habitat spatial complexity, can influence small mammal abundance patterns.

Highlights

ReseaRch aRticleModeling the effects of fire severity and spatial coMplexity on sMall MaMMals in yoseMite national park, california
Monroe and Converse (2006) found little temporal effect resulting from the season of prescribed fire on deer mice (Peromyscus maniculatus) and chipmunks (Neotamias spp.) in the southern Sierra Nevada, but little information exists on how spatial aspects of fire affect wildlife
All procedures were approved by the University of California, Davis, Institutional Animal Care and Use Committee, and met guidelines recommended by the American Society of Mammalogists (Gannon et al 2007)

Summary

ReseaRch aRticle

Modeling the effects of fire severity and spatial coMplexity on sMall MaMMals in yoseMite national park, california. We hypothesized that fire severity would influence the abundances of small mammals through changes in vegetation composition, structure, and spatial habitat complexity. Our results suggest that fire severity, with subsequent changes in vegetation structure and habitat spatial complexity, can influence small mammal abundance patterns. Fire severity refers to the magnitude of the effect that a fire has on the environment, and is commonly applied to a number of ecosystem components (van Wagtendonk 2006) Fire, both wild and prescribed, burn heterogeneously across landscapes, leaving behind a matrix of areas burned at various levels of severity, interspersed with unburned patches of various sizes and shapes. We hypothesized that fire severity would influence the abundances of small mammals via changes in vegetation composition, structure, and spatial complexity. We pursued our analyses on the four most commonly captured small mammals in our study area: deer mice, chipmunks, brush mice (Peromyscus boylii), and California ground squirrels (Spermophilus beecheyi)

Study Area

Plot Selection

Habitat Variables

Statistical Analyses

Habitat Models

Severity patch squareness indexd

Chipmunk species