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as 127° F (Oosting 1954). In addition to overexposure to halogens through wind deposits, salt
water inundation from overwash can disrupt and kill vegetation (Hancock 2009). Water can be a
limiting factor in the dune environment due to the drainage of rainwater through the soil (Au
1974, Hancock 2009). Plants adapted to survive in the harsh conditions allow for sediment
accrual by trapping sand brought in from winds and tide (Oosting 1954). These floral species
help to create and stabilize a dune environment.

Plant species of the dune environment can be categorized into one of several functional
groups (as defined by Shao et al. 1996, Stallins 2002, Crawford 2008). Dune builders, such as
Uniola paniculata, are upright species that trap sediment. Burial-tolerant plants adjust and thrive
in response to constant covering with sand. An example of a burial-tolerant plant is Hydrocotyle
bonariensis. Burial-intolerant species cannot withstand being covered with sand and are found in
the protected areas of barrier island ecosystems. Example burial-intolerant species are Oenothera
hematoma and Trichostema dichotomum. Species within these three functional groups can
change the topography of the dune system (Stallins 2002). A fourth type of plant functional
group found in the barrier island ecosystem is a passenger species. Passenger species do not
change the dune environment to any notable extent. An example of a passenger species is
Gaillardia punctatus. The burial-tolerant species, Hydrocotyle bonariensis, was the focus of this
investigation. Specifically, three questions were asked:

1) Is H. bonariensis merely a minor component of the barrier island dune habitat?
2) Could H. bonariensis be a suitable species for combining with sea oats for dune

revegetation and stabilization?
3) Can H. bonariensis plants be found spanning the dunal microhabitats supporting clonal

growth?

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