Identification and Mapping of Rare Plant Communities— State of Knowledge and Adoption of Standardized Techniques

Knowledge and protection of natural plant assemblages are key objectives of the California Native Plant Society (CNPS). The CNPS Vegetation Program has a floristic classification system to define and map vegetation in the state, including rare and common vegetation. Rare vegetation represents important and distinctive assemblages of biodiversity, and over 60% of the described vegetation alliances in California are rare or threatened. Since development pressures, climate change, invasive species, and other disturbances continue to threaten their existence, we need effective and efficient tools to identify and protect these rare types. CNPS is working collaboratively to establish a multi-step process to identify, map, and track rare vegetation throughout the state. Through an ad hoc committee, CNPS is adopting standardized techniques to collect reliable data, to evaluate rarity and monitor threats for each described vegetation type, to better inform agencies and land managers, and to strengthen our conservation efforts for preserving rare vegetation. Current techniques include standardized vegetation field survey protocols, detailed mapping using color aerial photography, classification and rarity ranking using a national system of the Natural Heritage Program, and estimation of total acreages and threats to rare vegetation assemblages. With these methods, we are working to establish key projects with other agencies, including California Department of Fish and Game, University of California, and United States Forest Service, to support efforts to identify and protect rare vegetation in different parts of the state.