Reports and Studies 2014 Review: 1975 Environment of Kiawah Report | Page 32

Summary & Analysis of the 1975 Kiawah Environmental Report 

maritime forests are dominated by live oak (Quercus virginiana), palmetto
(Sabal palmetto), yaupon holly (Ilex vomitoria) and wax myrtle (Morella
cerifera). Intertidal mud/salt flats occur on the back side of the island and
may intergrade into salt marsh or salt shrub thicket communities. These
flats are characterized by high salinity and irregular tidal flooding which
limits vegetation to a few, low-growing species able to tolerate hypersaline conditions. Tidal freshwater marsh and interdune pond communities
have mostly been augmented on Kiawah Island to create the system of
managed ponds that are found throughout. Brackish marsh communities
are found on the edges of ponds as well as along portions of interior
creeks replacing salt marsh communities as salinity declines. Maritime
grasslands dominate the dune systems for Kiawah and occur as pockets of
habitat intermixed within larger areas of maritime forest, maritime shrub
thicket and/or salt shrub thicket near the eastern and western ends of the
island.
The various ecological communities of Kiawah Island are constrained
by the underlying geology and current proximity to saltwater. Soils on
barrier islands reflect their sandy origins and are generally nutrient poor.
Freshwater is generally limited, while salt spray may inhibit plant growth.
Trees and shrubs nearest to the dunes will exhibit retarded growth and
height limits much lower than the same species occurring on the interior
of the island. These dwarfed individuals comprise parts of the maritime
shrub thicket. Similarly the combined effects of sandy, nutrient-poor
soils, salt spray and occasional strong offshore winds tend to produce a
shorter, mature maritime forest on a barrier island than on the mainland.
In general the maritime habitat is stressful to plants; limiting the
height and diversity of forests found on narrow barrier islands.
Environmental stresses that impact the native flora will also be expected
to impact non-native species as well. Invasive species are defined as nonnative plants that establish outside of where they are planted or naturalize. A vegetation survey of Kiawah Island was under taken to establish a
plant species list for the island, assess the plant communities on the
island, identify invasive or potentially invasive plant species, and develop
management guidelines for invasive plant species.
A major part of the 2012 report was devoted to problem species. Gramling identified the following non-native species to watch for their potential to threaten the
local environment:
Giant reed
Chinese silvergrass
Elephant ear
Sacred bamboo
Sago palm
Beach vitex
Gramling particularly noted that "beach vitex is a real threat to Kiawah Island. This
plant has a track record for invading dunes and encroaching upon turtle nesting
sites. A population of beach vitex was removed from the island (to my knowledge it
was the only population), but the threat is real."
Gramling also listed some "problem species." Among these are plants that are
already wide-spread: pampas grass, elaeagnus, and bamboo.
The final category Gramling refers to as "red alert species," and his section on
these is useful to repeat here:
There are some species that must be dealt with sooner rather than later
because they have significant ecological impacts in the short term. Non-native
wisteria can have detrimental effects on a tree by crowding out its leaves or
even by strangling younger trees. Escaped wisteria should be eradicated as
soon as it is found to prevent damage to other plants and inhibit the further
spread of this plant. Tree-of-heaven grows rapidly and spreads its
Revised: May 2014_REV 8

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