Field surveyed wetland perimeters at Saint Marks National Wildlife Refuge: 2010 - 2013

This dataset contains morphologic data from 32 wetlands, currently being monitored as part of the U.S. Geological Survey (USGS) Amphibian Research and Monitoring Initiative (ARMI) from Saint Marks National Wildlife Refuge (SMNWR). These data were used as a calibration dataset to inform a landscape classification procedure for depressional wetland identification. These sites covered a range of sizes, shapes, topographic and vegetative characteristics that should be representative of wetlands within the study area. Ground-based surveys of wetland perimeters were made using a Trimble R8 Real Time Kinematic Global Positioning System (RTK-GPS). In general, surveys followed the lowest extent of saw palmetto (Serenoa repens), which is a reliable indicator of the upper limits (elevation) of sustained inundation. In instances where palmetto was absent, margins were identified based on the lower limits of gallberry (Ilex sp.) and/or the upper extent of titi (Cyrilla/Cliftonia). These species occupied similar hydrologic and elevation zones as saw palmetto and, therefore, considered to also be reliable indicators of a wetland’s edge. GPS points were collected along this vegetative margin to represent the size and general shape of each wetland. In cases where dense vegetation prevented surveying the complete margin, we used elevation contours to connect distant points when digitizing perimeters.