California has embraced the US National Vegetation Classification System (NVC) as the standard for classification and mapping of vegetation. A state-wide Survey of California Vegetation (SCV) program residing in the State Department of Fish and Wildlife sets the standards for classification and mapping and has overseen classification and mapping of 50-60% of the state. Numerical analysis of thousands of samples classify the field samples into mapped units corresponding to lower and mid-level hierarchical units of the NVC classification and structural vegetation attributes. State and federal agencies funding this work have found it useful in a variety of ways. A recent economic analysis and user questionnaire summarizes the values of standardized vegetation classification and mapping and synthesizes its many benefits.
Results/Conclusions
In California, vegetation projects have been undertaken as an integrated process, including bioregional sampling, analysis, and reporting, followed by mapping based on the quantitative rules defined from the analysis and the NVC hierarchy. Social and economic benefits include: defensible and repeatable framework producing comparable results across jurisdictional boundaries; and identifying and accurately depicting rare and sensitive habitats for conservation in planning scenarios, which range in size from small projects to large multi-jurisdictional planning processes spanning of millions of acres.
Users of these products have identified a statewide, high-resolution digital vegetation map as one of their top framework data requirements. Users generally agree that they experience substantial time and cost savings when they can use SCV datasets rather than older, less detailed map products. The value extends to related uses such as accurate estimation of Carbon storage, and fire and fuels modeling. Users also find that when good quality standard data is lacking the coarse-resolution vegetation data available is insufficient for conservation planning, parcel acquisition, or assessment of development impacts.
A benefit-cost analysis shows a reduction in the number of permitting and zoning errors due to incomplete habitat knowledge, increased project productivity, and more ecologically sound preservation of natural resources. The scenarios considered in this analysis all produce positive net benefits. Depending on the scenario, the return on monetary investment ranges from 15% to over 550%. Based simply on monetary savings, the high-resolution SCV map of California will return benefits above and beyond its cost; a strong argument for using standard vegetation data throughout the U.S. and beyond.