Vegetation mapping at Chattahoochee River National Recreation Area: Photointerpretation key and final vegetation map

Cotten, David; Adams, Brandon; O'Hare, Nancy; Cooper, Christopher; Bernardes, Sergio; Madden, Marguerite

doi:10.36967/2266958

The University of Georgia Department of Geography’s Center for Geospatial Research (CGR), with the support of the National Park Service (NPS) Vegetation Mapping Inventory (VMI) Program, described and mapped vegetation at Chattahoochee River National Recreation Area (CHAT). This mapping effort was accomplished through collaboration with the NPS Southeast Coast Network (SECN), the North Carolina office of NatureServe (Durham, N.C.), and Atkins North America, Inc. Through the use of NatureServe vegetation plots, aerial photos, and data collected in the field, vegetation communities were delineated and assigned attributes. Using dominant vegetation classes and secondary vegetation classes as well as modifiers to describe the diversity of species, detailed draft vegetation maps were created for the Chattahoochee River National Recreation Area, both inside the park and within a 500-meter (1,640-foot [ft]) buffer. The buffer polygons and attributes were created on a broader scale using a system based on the Anderson Level II classification scheme, which includes anthropogenic and land use/land cover (LULC) classes. Within the park, the more detailed community element global (CEGL) codes were used. Because of the extensive past land use history, using the National Vegetation Classification System (NVCS) to the association level was challenging. Determining CEGL codes was particularly difficult because the National Vegetation Classification System was designed for relatively undisturbed vegetation communities. Through the use of NatureServe vegetation plots, aerial photos, and data collected in the field, vegetation communities were delineated and assigned attributes. Using dominant vegetation classes and secondary vegetation classes, as well as modifiers to describe the diversity of species, detailed vegetation maps were created for Chattahoochee River NRA, both inside the park and within a 500-meter (1,640-ft) buffer. The buffer size used for this study covered a much larger area than the region found within the park. This illustrates the linear nature of the park and how much it, including the river, is susceptible to land use land cover changes outside of the boundary. Chattahoochee River NRA covers approximately 3,000 hectares (7,413 acres [ac]) while the buffer contains approximately 10,700 hectares (26,440 ac). The majority of land use within the buffer, 57%, is residential. The most common vegetation classes found at Chattahoochee River NRA were Southern Red Oak—White Oak Mixed Oak Forest (7244) and Piedmont Dry—Mesic Basic White Oak—Hickory Forest (7232) with 10.4% and 9.9% of the park respectively. The smallest class was Southern Woolgrass Bulrush Marsh (3866) and Knotweed Pondshore and Ditchbank Vegetation (4966), at less than 0.05% each. Water, covering 19.2 % of the park, represents a higher percentage of area than any vegetation class. A rigorous accuracy assessment was conducted on the 30 map classes within the boundary of the park representing floristic types within the National Vegetation Classification System. Results showed an 82% map accuracy and a kappa rating of 81% using 356 accuracy assessment points. The products of this project include vegetation maps, a photointerpretation key, summary statistics of each vegetation class, and a detailed geodatabase with digital maps.

Vegetation mapping at Chattahoochee River National Recreation Area: Photointerpretation key and final vegetation map

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