Vegetation Mapping at Fort Pulaski National Monument

McManamay, Rachel; Curtis, Anthony; Heath, Sarah

The Southeast Coast Network (SECN) worked with the support of the National Park Service (NPS) Vegetation Inventory Program (VIP) to describe and map vegetation at Fort Pulaski National Monument (FOPU). This mapping effort was accomplished through collaboration with the Southeast regional office of NatureServe (Raleigh/Durham, NC). The mapping area is 2,543 ha, encompassing the entire boundary of FOPU and an additional buffered area of adjacent land. NatureServe ecologists identified plant associations for FOPU and a remote sensing specialist from the SECN completed the vegetation mapping using 1:12,000-scale, color-infrared aerial photography and digital orthophotography. NatureServe collected vegetation and environmental data from 17 vegetation classification plots, and the Remote Sensing Specialist assessed 47 observation points. Two Student Conservation Association (SCA) interns hired by the SECN conducted an accuracy assessment (AA), which entailed sampling 133 additional points. Fieldwork and mapping were completed between 2005 and 2013. A total of 25 map classes were developed to map the vegetation and general land cover of FOPU and surroundings, including the following: 12 map classes representing natural/semi-natural vegetation at the association level in the National Vegetation Classification System (NVCS), two map class representing cultural vegetation (e.g. developed) in the NVCS, and 11 map classes representing non-vegetated units (e.g. open water bodies, buildings, roads, etc.). Features were interpreted using 1:12,000 scale digital color-infrared aerial photography (flown 31 May 2009) through heads-up-digitizing in ArcGIS (Version 10.0, © 2010 Environmental Systems Research Institute, Redlands, California). Polygons were mapped to a 0.5-ha minimum mapping unit (MMU). A geodatabase containing various feature class layers and tables show the locations of vegetation types and general land cover (vegetation map), vegetation plot samples, AA sites, project boundary extent, and aerial photographic centers. The feature class layer for the FOPU vegetation map provides 251 polygons of detailed attribute data covering 2,543 ha, with an average polygon size of 11.2 ha. Of the area mapped, 177 polygons (70.5% of all polygons) represent natural/semi-natural vegetation types in the NVCS, encompassing 1,834.6 ha (72.1%) of the total map extent. Summary reports generated from the vegetation map layer indicate that the Southern Atlantic Coast Salt Marsh dominates the vegetated landscape (57 polygons covering 1,488 ha), with the Needlerush High Marsh (20 polygons, 91.4 ha) and the Cedar – Live Oak – Cabbage Palmetto Hammock (21 polygons, 52.9 ha) also covering a considerable portion of the park. The Southern Atlantic Coast Salt Marsh occupies the greatest area of any of the vegetation communities by far and is best developed in areas between mean high and low tides that are regularly flooded. The Needlerush High Marsh occurs within the salt marsh in areas slightly higher than where the Southern Atlantic Coast Salt Marsh is found. The Cedar – Live Oak – Cabbage Palmetto Marsh Hammock is a maritime forest community located on the highest elevations on Cockspur Island, typically on the older spoil deposits.

Vegetation Mapping at Fort Pulaski National Monument

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