Vegetation - Death Valley National Park [ds3305]

Death Valley National Park (DEVA) is a very large, 3.4-million-acre (1.4 hectares) unit of the National Park Service (NPS) located in California on the eastern border with Nevada. To better understand and document the vegetation diversity at DEVA, the NPS, the National Vegetation Inventory Program (NVIP), and the NPS Mojave Desert Inventory and Monitoring Network (MOJN) opened a vegetation inventory effort here in 2010. The NPS contracted the California Native Plant Society (CNPS) and the University of Nevada at Las Vegas (UNLV) to collect field data (111 classification plots and 518 observation points) for the project, which was combined with legacy data (1,242 samples) for analysis. CNPS analyzed the data to create the vegetation classification for the project following revised US National Vegetation Classification (USNVC) standards. 85 plant alliances and 186 plant associations were classified in DEVA as a result. NVIP then contracted Cogan Technology, Inc. (CTI) to create the digital vegetation map layer for the project area. The resulting spatial database and vegetation map layer were created using a combination of 2020 (California) and 2019 (Nevada) National Agriculture Imagery Program (NAIP) basemap data, ground-based verification efforts, and a two-step, or hybrid mapping approach that used both manual and automated techniques. By comparing the vegetation signatures on the imagery to the field data, 90 map units (74 vegetated and 16 land-use/land-cover) were developed and used to delineate the plant communities. The interpreted vegetation polygons were then digitized into a Geographic Information System (GIS) layer that was field-tested, reviewed, and revised. The map adheres to the USNVC standards. The minimum mapping unit (MMU) is 0.5 hectare (1.2 acres). CTI contracted Coast-to-Coast Botany and the Rio Grande Institute to collect the accuracy assessment (AA) field data alongside NPS. CTI then conducted the AA analysis. The final DEVA vegetation map layer was assessed for overall thematic accuracy at 82% with a Kappa value of 89%. More information can be found in the report and products, published here: https://www.nps.gov/im/vmi-deva.htm.