Fire in Chihuahuan Desert Grasslands: Effects on Soil Biot & Nutrient Cycling
Investigators (most current known information)
The proposed research will explore the influence of prescribed fire in a Chihuahuan Desert grassland on plant community composition and ecosystem processes, thus providing information on sustainable management of arid lands from both socioeconomic and biogeochemical perspectives. The role of fire in maintaining Chihuahuan Desert grasslands, from a historical perspective and as a contemporary management technique, remains controversial. Although several studies have reported decreased cover of native perennial grasses to fire, these are largely the result of short-term studies and little is known about longer term recovery. Furthermore, little is known about how fire influences biogeochemical patterns and processes in drylands. The overarching goal of this research is to assess the short- and long-term influences of fire in the Chihuahuan Desert grasslands on vegetation and biogeochemical pools in order to assess the ecosystem-level consequences of fire as a management tool. To understand the mechanisms behind changes in biogeochemical pools (soil C and N, plant available N and P), the researchers will explore the effects of fire on two important drivers of biogeochemical processes: soil biota and litter decomposition. The researchers aim to integrate the short-and longer-term influences of fire by investigating ecological responses both to a prescribed burn implemented for this experiment and to a historical experimental burn carried out seven years ago. This research explicitly addresses the IALC's 2008 theme. “Fire Ecology in Drylands” by addressing several topics from the 2008 RFP, including effect on prescribed burning, assessment of wildfires on ecological systems, post-fire revegetation, and effects of fire on soil properties. The proposed study will assess the short-term (18 months) responses to fire in experimentally burned plots in comparison to plots burned historically (7 years ago) and control (unburned) plots. Baseline measurements will be made during fall 2008 in all three treatments (new burn, old burn, and control; 6 replicate plots of each treatment) immediately prior to burning the new burn plots. Baseline measurements will include density and cover of vegetation and biogeochemical pools (soil organic carbon, total nitrogen, labile and recalcitrant carbon, plan available nitrogen and phosphorus). The researchers will follow short-term responses to burning by assessing among-treatment differences in vegetative cover, nutrient pools, soil biota, and leaf litter decomposition through a series of repeated measurements in the 18 months following the fall 2008 fire treatment. Among-treatment differences in soil biota and litter decomposition will be assessed due to their importance as drivers of biogeochemical pools, soil fertility, and ultimately plant community composition. To this end, microarthropods and nematodes will be extracted from soil cores in each plot, microbial biomass will be measured by substrate-induced respiration, and microbial functional diversity and catabolic profiles will be measured using microrespiration techniques with fifteen different carbon sources. Leaf litter decomposition will be assessed with an 18-month litterbag study using fiberglass mesh litterbags. The proposed research will provide important information on ecosystem-level responses to prescribed burning in desert grasslands that should ultimately be important in assisting with fire management.
No outcomes reported