Presentation by Dr. Rachel Gallery

ABSTRACT: Soil microbial communities that control nutrient transformation and storage in ecosystems are themselves influenced by landscape topography and vegetative cover. Disturbances such as fires and insect outbreaks are increasing in frequency and severity with enormous impacts on global carbon and nutrient cycling. We examine the effect of wildfire on successional changes in soil microbiota and ecosystem fluxes across a landscape with high topographic variation. We find that, layered over the topographic controls of hotspots of biogeochemical activity, fire alters organic substrate quality, microbial biomass, community structure, and activity. The resiliency of soil microbial communities to these heterogeneous disturbances determines rates of nutrient transformations as well as ecosystem structure and recovery.