Effects of fire on vegetation and small mammal communities in a Mojave Desert Joshua tree woodland

Wildfire size and frequency are increasing in Mojave Desert Joshua tree woodlands principally due to anthropogenic factors. These habitats are generally considered to be fire intolerant and the effects from fire are a major concern for land managers. This study investigated trends of ecosystem response to fire by looking at a chronosequence of historic burns. Plots were chosen at 2, 9, 13, 15 19, and 65 years since burn in which to sample vegetation and rodent communities. Rodent diversity was lower in burned plots and increased over time. The abundance of rodents however, was not significantly different between the burned and unburned plots. Vegetation showed a directional change in species composition with time since fire. However, reestablished vegetation assemblages did not converge to the assumed pre-burn condition. It is probable that this difference relates to the slow rates of establishment of certain vegetation components that make up the pre-burn condition of the plots. There is a concern that invasion by exotic plant species, nitrogen deposition, and global climate change may initiate a fire cycle in this ecosystem that will arrest succession before the Joshua tree woodland is allowed to reestablish.