MUSTANG ISLAND: VEGETATION AND SAND DUNES’ ROLE IN BARRIER ISLAND PRESERVATION

Mustang Island (MUI) is a barrier Island located on the Gulf Coast, stretching from Corpus Christi to Port Aransas. The island was created ~9000 years ago and has remained in its original location (Simms et al., 2006). The tidal range for MUI is less than 2 m. This could be one of the main reasons why the island has remained in the same place for so long (Simms et al., 2006). Factors playing into the well-being of an island include vegetation and sand dune formation. Certain types of vegetation endure the island’s dynamics better than others. Because vegetated sand dunes contribute to barrier islands’ well-being, (Dahl et al., 1975), it is important to analyze key factors to vegetation’s growth. During our observations, we noticed that the island is covered almost on its entirety of different types of grasses such as Uniola paniculata, Panicum amarum, Paspalum monostachyum, Croton punctatus, and this is a common pattern for MUI (White et al., 1978). What makes these grasses so resilient? What other factors affect the amount of grass coverage at MUI? Our hypothesis is that soil salinity, type of sand, and elevation affect directly the way vegetation grows, not only at MUI, but at barrier islands in general. To test this hypothesis, we have collected sand samples from MUI. We will perform salinity tests of the sand samples using the EC-170 Salinity Meter. Sand dune vegetation must be able to withstand high levels of salt (Dahl et al., 1975). It will be interesting to see if concentration of vegetation changes from location to location, according to salinity. We have collected elevation and location points of areas from where vegetation was collected as well. Correlation between elevation and vegetation points will be attained by creating models using R-studio software. Additionally, petrographic analysis of the sand’s grains will be attained using the petrographic microscope, for finding geologic history, provenance, and mineralogical composition of MUI’s sand (Garzanti et al., 2019).