Transect monitoring of wetland vegetation and elevation on Mustang Island, Texas By: Preston Mclaughlin  The Coastal and Marine Geospatial Lab (CMGL) is establishing a barrier-island wetland observatory on Mustang Island (Figure 1). The idea is to concentrate a number of mapping and measurement techniques in this area to gain a better understanding on how the various subenvironments will respond to sea level rise and climate change. So far we have conducted short coring for sediment accretion studies using Cesium 137 (Boris Radoslavjevic MS thesis) and installed marker horizons. We have also conducted airborne lidar surveys and are conducting repeated ground surveys along an earlier established transect. Future plans include sediment elevation tables and water level loggers. Figure 1. The CMGL wetland observatory uses various data collection and mapping techniques to study spatial and temporal changes in back-barrier subenvironments. Image Credit: Diana Del Angel On June 26th, Alistair Lord, Kevin Eager, Michael Rittenhouse and Preston McLaughlin performed field research on the bayside of Mustang Island State Park. Transect monitoring across upland and back-barrier wetland environments documented vegetation and topography. Previous surveys on this transect were conducted in November of 2010 and April of 2011. This information can be used to determine changes in ecosystem zonation, as well as the variations in vegetation type, cover, and height.   Figure 2. Alistair Lord (left) and Kevin eager (right) setting up the GNSS reference station at the datum. Photo Credit: Preston Mclaughlin               After arriving at the transect on the west end of Mustang Island State Park, a Global Navigation Satellite System (GNSS) reference station was placed on the reference datum (Figure 2), which was previously established by driving a steel rod 10+ meters into stiff Pleistocene sediments below the barrier island for stability. The research group then began to collect coordinate points using the GNSS Real Time Kinematic system (Figure 3), this system allows for the collection of coordinates and elevation with accuracies within a few centimeters. Photographs were taken with the GPS camera at each coordinate point to visually document the type of vegetation within that particular area.  Written notes on vegetative taxonomy, percent cover, height of vegetation, and type of geo-environment were also recorded at every point.  Coordinate points were roughly distributed every 5 meters in the constantly fluctuating geographic portions of the transect.  10 meter spaces were used in the tidal flats due to the lack of vegetation and the flat surface.  A total of 234 points were collected along the 2000 meter transect that extended from the back-barrier upland to the first sandbar around 25 meters past the shoreline.   Figure 3. Kevin eager (center) using the GNSS RTK system to record a coordinate. Michael Rittenhouse (right) documents vegetation information. Photo Credit: Preston Mclaughlin