E. Cayenne Engel
Friday, October 17, 2008 - 2:00-2:30
Large fires are increasingly common across the landscape in the Mojave Desert, especially in years with above average rainfall. These fires can be largely attributed to the presence of exotic plant species, particularly grasses in the Bromus genus. During 2005 above average winter and spring precipitation led to increased vegetative production for native and non-native species. This biomass readily carried wildland fires that burned nearly 1 million acres of Clark County, NV, in 2005 alone. During winter 2007 and Spring 2008 we surveyed burned and adjacent unburned sites in Mojave Desert shrubland communities throughout Clark County, to assess plant community recovery. We quantified the cover of the perennial species and related their presence and abundance to abiotic site characteristics and soil chemistry. Additionally, we are monitoring the success of seeding perennial shrub species to burned sites to evaluate the effectiveness of this strategy for accelerating community recovery. After two years, community composition varied dramatically by site, with few of the formerly dominant species such as Creosote, Bursage, and Blackbrush returning. However, other common shrubs such as Globemallow have reestablished at many of the sites where they were present pre-burn. Perennial species richness did not differ among sites, but identity and abundance varied dramatically. To date, seeding has not impacted the abundance of forbs and shrubs. Seed bank analyses should detect whether the added seeds are still present in the seed bank. Understanding the process of post-fire recovery in an increasingly fire rich landscape will help inform effective management strategies.
Keywords: MOJAVE, FIRE ECOLOGY, BROMUS MADRITENSIS, SEEDING, SUCCESSION