Testing the Interactions Between Invasive Perennial Pepper Weed and Ecosystem Function in Tidal Marshes of the San Francisco Bay-Delta

Start/End: September, 2013 to August, 2015

This project will explore the ecological role and impact of a highly aggressive, non-native plant in the mustard family, known as perennial pepper weed (Lepidium latifolium). Native to Europe and Central Asia, the noxious weed has invaded sensitive tidal wetlands of the San Francisco Bay-Delta and Suisun March, elbowing out native marsh plants, including the endangered endemic softbird’s beak. The core of the project will be a series of field-manipulation experiments, in which pepper weed densities are varied in plots with naturally occurring native plant communities to evaluate the weed’s ecological consequences at various stages of invasion. Experiments will seek to quantify the weed’s impact on carbon storage, marsh plant productivity and food webs at sites with different salinity exposures. Findings may provide important insights into cost-effective control strategies for the weed and their implications for marsh restoration.

Research mentor: Ted Grosholz, UC Davis

Community mentor: Brenda Grewell, USDA