The Texas Gap Analysis Project (TX-GAP) is part of a nationwide effort to document the spatial distribution of biodiversity and assess its representation by the current conservation system. The objectives of TX-GAP are: (a) to develop a map of current land cover of Texas from recent Landsat TM satellite scenes; (b) to estimate potential distribution of Texas wildlife vertebrate species; (c) to depict and map land-stewardship categorized by level of conservation; and (d) to combine the above data layers in a GIS and perform analyses of species richness patterns relative to known levds of land conservaffon and management. There are 52 Landsat scenes covering the sate of Texas. Scenes with pixels representing 30 x 30 m areas are classified with Spectrum software to label vegetation type in accordance with the Nature Conservancy identification of vegetation at the alliance levy. Fifty to 200 points per scene are being used to ground truth scones in West Texas. Aerial videography provides an additional level of data to interpret the Landsat imagery. Seventeen scenes in West Texas have now been tentatively classified.
Wildlife Habitat Relationships (WHRLs) for Texas vertebrates are be" prepared bed upon habitat affinities for vegetation type, soil type, precipitation, elevation, temperature, and other abiotic and biotic factors. WHRL databases are approximately 25% complete for mammals, 50% for herptiles, and 50% for birds. We anticipate completion of all vertebrate databases this year. Completed WHRLs are used in the context of a Geographic Information System to map the distribution of Texas vertebrates. These maps are then in turn used to evaluate the status of biological diversity in the state and ultimately the nation. These maps and other data will be available to the public and resource managers through the World Wide Web, computer discs, and published reports as to guide land-use planning and development.
An initiative from the Biological Resources Division of the U.S. Geological Survey, warlord through the Environmental and contaminants Research Center, ale Texas Cooperative Fish and Wildlife Research Unit, the National Gap analysis Program and with Lion of the Mexican agency National commission for the Knowledge and Use of Biodiversity, has been funded to extend TX-GAP into Mexican lands adjacent to the Lower Rio Grande (Rio Bravo) River. The study area proposed involves a region covered by fourteen Landsat TM scene areas that span the Lower Rio Grande River plus six adjacent scene areas wholly in Mexico. The tran-national Rib Grande Gap Isis Project will cover a buffer areas approximately 150 hen wide to each side of the border. The protect veil generate valuable geography and biological dab sets to support binational efforts for conservation and land-use planning, provide opportunities for biological data sharing and the potential standardization of procedures applicable in this region with common ecological chalks. Maps, dab and products produced in this bawd project wit be distributed tough Me World A/ de Web, computer discs and published reports in both Spanish and Erg.
Reprinted from: 25 Years of Cultural and Natural Resource Stewardship, Research and Resource Management Symposium. April 22-25, 1998. Carlsbad,NM.
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