Abstract
Geographic Information Systems (GIS) have become an important tool in conservation biology. From identifying conservation priority areas to managing plant genetic diversity, GIS analysis is a key resource in evaluating and assessing biodiversity throughout the world. Researchers studying global biodiversity have identified 25 areas of extraordinary biological diversity, colloquially termed hotspots. A hotspot contains high densities of endemic species and is also in danger due to significant and ongoing habitat loss. Anthropogenic activities such as mining, urban development, and farming are major players in endangering hotspots. Napa County lies within the heart of one of the world’s 25 known biological hotspots. The California Floristic Province contains high numbers of native and endemic plant species. Agriculture is the leading industry in Napa County, contributing nearly a half a billion dollars per year to California’s economy. Unfortunately, agricultural activities are some of the leading contributors that threaten biodiversity in Napa County. Conservation of species and ecosystems are an important task facing the County. v A Geographic Information System (GIS) was employed to examine how future vineyard expansion will affect biodiversity within Napa County, and that geospatial analysis can identify areas of threatened biodiversity due to vineyard expansion. There were 3 objectives of this research; 1) To predict future vineyard locations throughout Napa County through GIS analysis, 2) to identify ecosystems and special status species that will be threatened by future vineyard development and 3) to detect potential disruption of wildlife corridors due to vineyard growth. The research was organized into four phases to address objectives 1–3. Phase 1 included development of an existing vineyard GIS layer. Phase 2 analyzed current literature and existing vineyards to reveal physical and geographic characteristics of existing Napa county vineyards. Phase 3 applied the revealed existing vineyard characteristics to all of the remaining land within Napa County in order to find out where future vineyards were most likely to be located. And phase 4 analyzed impacts to biodiversity resulting from future vineyard expansion. Results from phase 4 revealed four critical ecosystems that could potentially lose from 51% to 93% of their total area within the County. Twenty-three special status species from six different taxon groups were identified. Impact analysis revealed eleven out of the twelve botanical species experienced potential habitat loss of 59% or above from potential vineyard expansion. The Bald eagle showed a 57% habitat loss, the most loss out of the 5 bird species studied. Both amphibians and mammals were represented by one species each and included the California red-legged frog and Salt-marsh harvest vi mouse. Both species showed less than a 30% reduction in habitat. Three invertebrates were analyzed and the Valley elderberry longhorn beetle was shown to potentially lose 65% of its habitat due to viticulture. Thirty nine potential corridors in danger of disruption due to an increase in vineyard development were identified. Utilizing GIS analysis to visualize and determine habitat fragmentation that potentially may affect biodiversity, species rich patches were prioritized for corridor connectivity; and intended to provide reconnaissance level identification of corridor locations within Napa County for natural resource experts and conservation planners. The results from this analysis can benefit wildlife management and land-use decision making within the County.