Vegetation mapping at Fort Matanzas National Monument: Photointerpretation key and final vegetation map

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

doi:10.36967/2266813

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 Fort Matanzas National Monument (FOMA). 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 Fort Matanzas NM was created to represent the vegetation occurring within the park during 2012. This product represents the final of four steps necessary to produce an accurate vegetation map based upon aerial photographs. This includes determining the community element global (CEGL) codes (2008) and acquisition of aerial imagery (2012), using the aerial imagery, with 21 ground truthing points (2014, 2015), 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 park plus an additional 500-meter (1,640-foot [ft]) buffered area. 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 eight NatureServe vegetation plots, 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 Fort Matanzas 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 park, the more detailed National Vegetation Classification System was used. The most common class found in Fort Matanzas NM is 7032—Maritime Live Oak Hammock, covering 38% of the park, followed by the combination class 39227 (3956—Saltwort—Woody Glasswort Dwarf—shrubland and 2278—Salt Flat—Woody Glasswort Type), covering almost 24% of the park. Non-NVCS classes cover 12% of the park, with the most dominate non-NVCS class being sand and covering 7% of the park. A rigorous accuracy assessment was conducted on the six map classes within the boundary of Fort Matanzas NM representing floristic types within the National Vegetation Classification System. Results showed a 70% map accuracy and a kappa rating of 62% using 40 accuracy assessment points. The products generated from this project include a vegetation map, a photointerpretation key, summary statistics of each vegetation class, and a detailed geodatabase with digital maps.

Vegetation mapping at Fort Matanzas National Monument: Photointerpretation key and final vegetation map

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