National Park Service Vegetation Inventory Program: Buffalo National River, Arkansas [and associated files]

Hop, Kevin; Lubinski, Sara; Dieck, Jennifer; White, Rickie; Pyne, Milo; Foti, Tom

The USGS Upper Midwest Environmental Sciences Center, NatureServe, and NPS Buffalo National River (BUFF) have completed vegetation classification and mapping of the BUFF. Photointerpreters, ecologists, and botanists collaborated to identify and describe vegetation types within the National Vegetation Classification Standard (NVCS) and to determine how best to map them by using aerial photographs. The team collected 250 vegetation sampling plots within the BUFF. Furthermore, data from 891 accuracy assessment (AA) sites were collected (of which 889 were used to test accuracy of the vegetation map layer). These data sets led to the identification of 56 vegetation types at the associations in the NVCS at BUFF. Two additional vegetation types are recognized at the group level in the NVCS. A total of 29 map classes were developed to map the vegetation and general land cover of BUFF, including the following: 26 map classes representing natural/semi-natural vegetation types in the NVCS, one map class representing cultural vegetation (e.g., developed lands) in the NVCS, and two map classes representing non-vegetation features (e.g., open-water bodies). Features were interpreted from viewing color-infrared aerial imagery dated October 2006 (during fall leaf change) via digital-onscreen three-dimensional stereoscopic workflow systems in geographic information systems (GIS). The interpreted data were digitally and spatially referenced, making the spatial database layers usable in GIS. Environmental models were used to further separate vegetation types where visual interpretation was limited or not possible. Polygon units were mapped to either a 0.5 ha or 0.25 ha minimum mapping unit, depending on vegetation type. Ancillary sets of aerial imagery from November 2005 (near leaf off) and from the 1930s (historic land use) were used for additional reference during mapping. A geodatabase containing various feature-class layers and tables show the locations of vegetation types and general land cover (vegetation map), vegetation plot samples, AA sites, project boundary extent, and aerial photographic centers. The feature class layer for the BUFF vegetation map provides 11,279 polygons of detailed attribute data covering 37,828.4 ha, with an average polygon size of 3.4 ha. Summary reports generated from the vegetation map layer indicate that 11,129 polygons (98.7%) represent natural/semi-natural types in the NVCS and encompass 36,421.4 ha (96.3%) of the total map extent. The Mixed Oak - (Hardwood) Dry Forest (FDO) is the dominant map class, according to both frequency of occurrence and area coverage. The FDO map class contributes 2,692 polygons (23.9% of all polygons) and covers 18,978.9 ha (50.2% of all area), with an average polygon size of 7.1 ha. A thematic AA study was conducted of map classes representing natural/semi-natural types in the NVCS. Results present an overall accuracy of 78.9% (kappa index of 77.3%) based on data from 889 of the 891 AA sites. Most individual map-class themes exceed the NPS VIP standard of 80% with a 90% confidence interval. The BUFF vegetation mapping project delivers many geospatial and vegetation data products in hardcopy and digital formats. These products consist of an in-depth project report discussing methods and results, which include descriptions and a dichotomous key to vegetation types, map classification and map-class descriptions, and a contingency table showing AA results. The suite of products also includes ground