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Treesearch

Evaluating threats posed by exotic Phytophthora species to sensitive plant communities in the Santa Clara Natural Community Conservation Plan area

Informally Refereed
Download (PDF 655 KB): https://research.fs.usda.gov/download/treesearch/60489.pdf

Abstract

Root rots caused by exotic Phytophthora species have been associated with dying and declining vegetation in multiple native plant communities in the San Francisco Bay Area and elsewhere in northern California. This project focused on detecting Phytophthora species that are currently affecting or have the potential to seriously affect populations of covered plants in the Santa Clara Valley Habitat Conservation Plan/Natural Community Conservation Plan (HCP/NCCP) area (Swiecki and Bernhardt 2018). A key component of the Santa Clara Valley HCP/NCCP is the creation of an 18,800 ha reserve network within the plan area to protect and conserve covered species, natural communities, and ecosystem function in perpetuity. We developed a sampling strategy by using GIS data to determine where in the plan area various priority habitat types with Phytophthora-susceptible vegetation might be exposed to Phytophthora contamination from roads, trails, past restoration plantings, or other known risk pathways. High-priority vegetation included rare and threatened species, as well as vegetation complexes that were poorly represented in the plan area. We also considered proximity to lands enrolled or proposed for enrollment in the HCP/NCCP reserve system, access, and in-field observations of vegetation symptoms and risk factors to determine sampling locations.

Parent Publication

Citation

Swiecki, Tedmund J.; Bernhardt, Elizabeth A.; Hillman, Janell. 2020. Evaluating threats posed by exotic Phytophthora species to sensitive plant communities in the Santa Clara Natural Community Conservation Plan area. In: Frankel, Susan J.; Alexander, Janice M., tech. cords. Proceedings of the seventh sudden oak death science and management symposium: healthy plants in a world with Phytophthora. Gen. Tech. Rep. PSW-GTR-268. Albany, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Research Station: 40-44.