Vegetation mapping at Timucuan Ecological and Historic Preserve: Photointerpretation key and vegetation map

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

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 Timucuan Ecological and Historic Preserve (TIMU). 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 Timucuan Ecological and Historic Preserve 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 the determination of the community element global (CEGL) codes (2008) and acquisition of aerial imagery (2012), using the aerial imagery, with 162 ground truthing points (2014, 2015), to create a draft vegetation map, performing an accuracy assessment (2016), and then using all the available information to create a final vegetation map (2018). The total mapping area encompassed the entire boundary of the preserve plus an additional 500-meter (1640-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 NVCS was designed for relatively undisturbed vegetation communities and Timucuan EHP has an extensive human- influenced land-use history. Using 73 NatureServe vegetation plots within and adjacent to the park, 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 further describe the classifications, detailed vegetation maps were created for Timucuan EHP. Within the preserve, the more detailed NVCS was used. The implementation of the Florida State Wildlife Action Plan (SWAP) vegetation classification system was additionally used within the park as supplemental information (Kawula 2014). Where it was possible, attempts were made to create a cross-walk between this localized system and the national NVCS CEGL codes. Polygons and attributes created within the 500-meter (1,640-ft) buffer used the same classification system and modifiers as within the park. 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. The most prevalent vegetation class found in Timucuan EHP was Southern Atlantic Coast Salt Marsh (4191) covering 24.71% of the park. Rivers were the second most prevalent class at 22.77%, followed by Needlerush High Marsh (4168) at 20.93%. The map accuracy assessment (AA) showed 72% accuracy and a kappa rating of 69% using data from 313 AA plots.

Vegetation mapping at Timucuan Ecological and Historic Preserve: Photointerpretation key and vegetation map

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