Gap analysis of biodiversity in California

TitleGap analysis of biodiversity in California
Publication TypeConference Paper
Year of Publication1991
AuthorsDavis, FW, Stoms, DM
Conference NameSymposium on Biodiversity of Northwestern California
Date Published1991
PublisherUniversity of California Wildland Resources Center
Conference LocationSanta Rosa, California
Keywordsgeographic information system, Wildlife-Habitat Relationships System, vegetation mapping

Most conservation efforts in California are conducted at local to sub-regional scales, and focus on species or communities of special concern. Currently lacking is an overview of the protection status of species and communities both statewide and in the western U.S. This paper describes a GIS-based Gap Analysis of biodiversity that is part of a national program being coordinated by the U.S. Fish and Wildlife Service. "Gap Analysis" is the evaluation of the protection status of plant communities and vertebrate species by GIS overlay of biological distribution data on a map of biological reserves. The biodiversity assessment for California is using existing digital geographical data sets on land ownership, topography, species ranges and locations of threatened and endangered species. An up-to-date statewide vegetation map is being produced using digital Thematic Mapper (TM) satellite data. The vegetation map is used in conjunction with the California Wildlife Habitat Relationships (WHR) System and digital species range maps to predict potential distributions of native terrestrial vertebrates. Research to date has concentrated on the south coastal region, and has been involved in compiling existing data sets, refining mapping methods and testing the sensitivity of the biodiversity assessment to map scale and minimum mapping unit. A hybrid method of digital image classification and manual image interpretation has been developed that appears promising. Test areas exhibit very different scales of vegetation pattern and different sensitivity to data resolution, implying the need for different minimum mapping units for different physiographic regions of the state.