Vegetation Mapping at Castillo de San Marcos National Monument: Photointerpretation Key and Final Vegetation Map

Cotten, David; Healy, Shannon; Adams, Brandon; O'Hare, Nancy; Bernardes, Sergio; Jordan, Thomas; Madden, Marguerite

doi:10.36967/2266926

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 Castillo De San Marcos National Monument (CASA). This mapping effort was accomplished through collaboration with the NPS Southeast Coast Network (SECN), the North Carolina office of NatureServe (Durham, N.C.), and Amec-Foster-Wheeler Environmental & Infrastructure, Inc. A final vegetation map for Castillo de San Marcos National Monument was created to represent the vegetation occurring within the park during 2012. This product is the final of four steps necessary to produce an accurate vegetation map based upon aerial photographs. This includes the determination of the community element global (CEGL) codes (2008) and acquisition of aerial imagery (2012), using the aerial imagery, with five ground truthing points (2014), to create a draft vegetation map, performing an accuracy assessment (2015), and then using all the available information to create a final vegetation map (2018). The total mapping area encompassed the entire boundary of the monument plus an additional 500-meter (1,640-foot [ft]) buffered area. Using one NatureServe vegetation plot, color-infrared 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 Castillo de San Marcos NM. Polygons and attributes within the 500-meter (1,640-ft) buffer 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 monument, the more detailed National Vegetation Classification System (NVCS) was used. The most common class found in Castillo de San Marcos NM is the combination class 14002 (4701—Bermuda Grass Semi-natural Pasture and 4883—St. Augustine Grass Herbaceous Vegetation). This class covers approximately 60% of the Monument. The smallest class in the park is the combination class 13008 (3956—Saltwort—Woody Glasswort Dwarf—shrubland 3956 and 2278—Salt Flat (Woody Glasswort Type), covering less than 0.5% of the entire park. A rigorous accuracy assessment was conducted on the four map classes within the boundary of Castillo de San Marcos NM representing floristic types within the National Vegetation Classification System. Results showed an 80% map accuracy and a kappa rating of 100% using 10 accuracy assessment points. The products generated from this project include vegetation maps, a photointerpretation key, summary statistics of each vegetation class, and a detailed geodatabase with digital maps.

Vegetation Mapping at Castillo de San Marcos National Monument: Photointerpretation Key and Final Vegetation Map

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