St. George Island

Dune Vegetation Dynamics

Research Methods

We have established permanent locations on the eastern tip of St. George Island, Florida (Figure 1) where we have monitored the vegetation annually since 1998 (unfortunately, no data were collected in 2002). The site is in a well-protected area of St. George Island State Park where research permits have been re-issued to T. Miller by the FDEP to work on a variety of projects since 1992. Six large grids (60 m x 60 m) each consisting of a 7 x 7 array of 1 m2 plots were marked out using wooden stakes, with each plot 10 m apart (Figure 1). Two grids were placed across foredunes, two in the interdune area, and two in the backdunes, for a total of 294 plots. A 1-m2 quadrat has been placed over each plot in the fall of each year (late October or early November) and all vegetation counted by # individuals, # clumps, and/or % cover. This work has been conducted by volunteers: to insure consistency, census teams always contained one trained botanist. Each group used standardized keys that we have created; any unknown plants were sampled off the plots in replicate, given an ID number and identified later. Other aspects of each plot were also noted, such as dead plants or evidence of flooding or sand movement.

 

 

We also collected data on some environmental variables associated with each plot. Gravimetric percent soil moisture was determined in 1999 by collecting a 2 cm diameter x 15 cm column of sand from a corner of each plot. Each sample was placed in an airtight bag, and later weighed, dried at 60°C, and re-weighed to determine percent soil moisture. Percent ash was determined using the same samples and reweighing the samples after being heated in a combustion furnace. The elevation of each plot relative to mean sea level was determined in 2007 using a TopCon Total Station.

Climate records have been obtained from Apalachicola, FL, providing data on weather and precipitation (National Estuarine Research Reserve System) and storm surge (NOAA).