Great Basin National Park (GRBA) covers approximately 31,258 hectares (77,180 acres) in east central Nevada along the Utah border. The park was established to preserve a representative segment of the Great Basin region and to promote an understanding of the natural and cultural heritage of this physiographic region. GRBA gets its name from its location in the Great Basin desert region of the United States but more closely resembles the “ranges and basins” geologic province, due to the South Snake Range located in the center of the park. The South Snake Range creates a rugged landscape containing many natural and unique vegetation types including sparse alpine cushion plants and ancient bristlecone pine forests. To better understand and document GRBA’s vegetation and to establish a baseline for comparison against future conditions the National Park Service (NPS) and the NPS Mojave Desert Network Inventory and Monitoring Program (MOJN I&M) started a GRBA vegetation inventory effort in 2007.
A five-year, four phase program was initiated to complete the task of classifying and mapping the vegetation at GRBA. Phase one was conducted by a combination of botanists and ecologists from NPS, MOJN I&M, GRBA, and NatureServe who collected 340 classification plots, observation points, and rapid assessment points across much of the park. In phase two, all of the field data was analyzed by NatureServe to classify 105 associations and 31 GRBA-specific vegetation types using the revised U.S. National Vegetation Classification (rUSNVC). Phase three, directed by Cogan Technology, Inc (CTI) produced a digital vegetation map that was validated using 70 independent data points. In the final phase, contracted scientists from Logan Simpson, Inc collected 872 stratified random accuracy assessment (AA) points to check and finalize the map.
GRBA’s spatial database and map layer was produced from high-resolution 2007 Digital Map, Inc. imagery provided to CTI by the NPS. By comparing the signatures on the imagery to field and ground data, 64 map units (48 vegetated, four barren geology and snow, and 12 land-use / land-cover) were developed and the vegetation map units were directly cross-walked or matched to their corresponding rUSNVC plant associations. The interpreted and remotely sensed data were converted to Geographic Information System (GIS) spatial geodatabases and maps were printed, field tested, reviewed, and revised. The final map layer was accessed for thematic accuracy by creating contingency tables and the final overall accuracy of the map layer was determined to be 84% with a Kappa value of 82%.
Products developed for GRBA are described and presented in this report, as well as stored on the accompanying DVD. These include:
• A Final Vegetation Inventory Report that includes keys to the vegetation and imagery signatures, AA information, and all of the project methods and results
• A Spatial GIS Database containing spatial data for the vegetation, plots, and AA points
• Digital Photos from the field sampling efforts
• Metadata for all spatial data (Federal Geographic Data Committee -compliant)
• Vegetation Descriptions and Photo Signature Key to the associations and map classes.
