Large fires are increasingly common across the landscape in the Mojave Desert, especially after exotic annual grass biomass has accumulated following years with above average rainfall. However, little is documented about the natural progression of post-fire recovery in the Mojave. The lack of information about how desert ecosystems recover after fire makes defining management prescriptions challenging and often creates guesswork for federal land managers. Understanding the dynamics of how Mojave systems recover after fires can aid managers by enabling them to understand which factors most strongly influence natural succession and plant re-establishment. From winter 2007 through spring 2009 we sampled plant community composition in burned and adjacent unburned plots within Mojave Desert shrubland communities. Fire age ranged from 2 – 30 years. Our goals were to associate biotic and abiotic factors with plant community recovery and reveal landscape level patterns for which factors influence community recovery. To do this, we quantified the foliar cover of perennial species and related their presence and abundance to abiotic site characteristics, soil chemistry, and unburned plant community composition. We used multivariate analyses and ordination techniques to examine our data.
Results/Conclusions We found that unburned plant community composition and initial community type (creosote, yucca, or blackbrush dominated) generally were not associated with the recovery rate on burned plots. Site descriptors, such as elevation and latitude, were associated with community composition in both burned and unburned sites. However, burned and unburned communities were driven by different environmental, soil, and biotic variables. Burned plant community composition was associated with soil texture and total soil nitrogen; unburned plant communities were more closely associated with specific soil micronutrients. It appears that after burns in blackbrush communities dominant species fail to return for at least 20 years, while creosote and yucca dominated communities recover more quickly with dominant species re-establishing or resprouting, but still not in pre-fire abundances. Understanding the process of post-fire recovery in an increasingly fire-rich landscape will help managers design effective restoration strategies where necessary, and prioritize sites based on the likelihood of natural regeneration.
