Approaches for mapping California's coastal wetlands, beaches and dunes, eelgrass, and rocky intertidal habitats.
Managing California’s coastal habitats and tracking progress toward achieving regional and statewide goals requires up-to-date and comprehensive mapping to assess extent and track change in total area and habitat distribution over time. To date, mapping of different coastal habitats in California has occurred periodically and often in a piecemeal manner. This lack of comprehensive statewide coverage, lack of consistent methodology, and asynchronous temporal collection makes it difficult to achieve the objectives of California’s resource managers.
To remedy this situation, the California Ocean Protection Council (OPC) summarized options for routinely and comprehensively mapping four coastal habitats statewide: coastal wetlands, beaches and dunes, eelgrass, and rocky intertidal. This effort is intended to support OPC’s Strategic Plan goals on coastal habitat acreage targets and to support other State agencies in their mandates to track habitat acreages (California’s Nature-Based Solutions Climate Targets AB1757, 2022 C. Garcia). Expert workgroups were convened for each of the four habitats to provide input on mapping approaches and data sources.
Standard definitions were developed for each habitat and various approaches were considered in terms of their ability to discern important boundary attributes across all regions of California. The workgroups evaluated tradeoffs associated with each mapping approach as well as the suitability of currently available imagery and elevation/topographic data. Each approach will likely leverage several different geospatial analyses, which are discussed in greater detail within the report.
Mapping approaches were evaluated based on their applicability/ability to discern key boundary attributes and the availability and applicability of major data types. Data derived from satellites, airplanes, Unoccupied Aircraft Systems (UAS), and other field-based sensors and surveys were considered. Each mapping approach considered provides a different level of accuracy and detail. Some types of change may be possible to detect from more coarse mapping of habitat, where others may only be detected through more detailed and higher resolution data and mapping. This information will help inform the development of ongoing mapping efforts that can be applied in a consistent, practical, and effective manner across California.
This report was produced by OPC, and prepared by the San Francisco Estuary Institute and Southern California Coastal Water Research Project.
