Vegetation Classification and Mapping of Gauley River National Recreation Area, West Virginia

Vanderhorst, James; Streets, Brian; Arcaro, Zachary; Gawler, Susan

A vegetation classification and map were developed for Gauley River National Recreation Area (GARI) by the West Virginia Natural Heritage Program following standards of the U.S. Geological Survey / National Park Service Vegetation Mapping Program. Standards include a minimum mapping unit of 0.5 ha (1.23 ac) and classification accuracy of 80% or greater for each map class. The U.S. National Vegetation Classification (USNVC) was used as the standard for vegetation classification. Classification was based, in part, on multivariate analysis of complete floristic data from 220 plots sampled in 1995–2009. Plots were stratified to cover the geographic range and ecological gradients within the park. Multivariate analyses of plot data included hierarchical agglomerative cluster analysis, non-metric multidimensional scaling, and indicator species analysis. The classification for the park was crosswalked to the USNVC in consultation with NatureServe. Vegetation of the park is classified in 23 associations of the USNVC, including 14 upland associations and 9 riparian and wetland associations. Prevailing physiognomic expressions include 17 forest associations, one woodland association, three herbaceous associations, one non-vascular association, and one sparse vegetation association. Two riparian associations new to the USNVC, the Riverscour Shrub Prairie and the (Virginia, Pitch) Pine Floodplain Forest, are recognized and described for the first time based on plots from GARI and from other rivers in West Virginia. A digital vegetation map for GARI was developed as a personal geodatabase using Environmental Systems Research Institute (ESRI) ArcGIS software. The geodatabase includes a point feature class for locations of plots and two polygon-feature classes (clipped by the park boundary and unclipped) for vegetation, including non-vegetated land cover. Delineation of vegetation map classes was based on interpretation of a digital orthophoto mosaic developed by North Carolina State University (NCSU) from leaf-off color infrared aerial photography flown in March 2003. The vegetation map includes 31 map classes. Upland communities comprise about 86% of the park area and are represented by 13 map classes. Two upland map classes each include patches of two associations, all others represent single associations. Six major upland forest associations (Eastern Hemlock - Oak - Sweet Birch / Great Laurel Forest, Sugar Maple - Yellow Buckeye - American Basswood Forest, Oak - Hickory Forest, Oak - Hickory - Sugar Maple Forest, Eastern Hemlock Plateau Forest, and Oak / Great Laurel Forest) comprise about 80% of the park area. Riparian and wetland communities comprise about two percent of the park area and are represented by nine map classes. One riparian map class is comprised of multiple associations, all others represent single associations. Six percent of the park is mapped as natural waterways, and the remaining five percent is mapped as disturbed areas and cultural and transportation features. Spatial and thematic accuracy assessments were performed by NCSU. Thematic accuracy of 23 map classes was assessed, excluding seven non-vegetated map classes and one vegetation map class known from just one polygon. Producer’s and user’s accuracies of individual map classes range from 33% to100%. Overall thematic accuracy of the vegetation map is estimated to be 87.1%. 10

Vegetation Classification and Mapping of Gauley River National Recreation Area, West Virginia

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