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Current and Recent Research Projects

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Research in coastal sage scrub (CSS) ecosystems 

The role of cryptobiotic soil crusts and vascular plants in patterning microbial communities in CSS ecosystems

We are investigating how biological soil crusts of varying levels of successional development and the dominant vascular plants of the CSS affect soil microbial communities and processes. We have found that the cyanobacteria and lichens in soil crusts support a particularly novel and specialized community of heterotrophic bacteria.

Soil crusts grow in bare patches between shrubs in CSS.  These crusts are held together by polysaccharides produced by cyanobacteria, algae and lichens, and harbor unique microbial communities.

Effects of Invasive plant species and fire on microbial communities and soil processes in CSS

We are studying how disturbance by fire and invasion in CSS affects microbial communities and the cycling of C, N and water, and how these changes might feed back to influence the plant communities and the ecosystem.  Much of this research is performed with the cooperation of the Soil Ecology and Restoration Group (SERG) and the laboratories of Douglas Deutschman and Janet Franklin

CSS ecosystems are endangered by human development, disturbance and invasion by exotic plant species.

Native CSS shrubs and exotic grasses differ greatly in their litter chemistry, and their rates of growth, N uptake and transpiration. This can lead to altered biogeochemical cycling and microbial community structure (as was shown in this greenhouse experiment)