waters and algae and sedentary invertebrates (hydroids, bryozoans, sponges, barnacles, oysters and mussels) in estuarine and near-shore marine waters.
Rock seawalls and jetties provide hardened substrate for attachment of organisms in intertidal and subtidal zones and exposed rock may be used by resting and foraging shore and seabirds, most notably the purple sandpiper (Calidris maritima), which prefers rocky coast habitats that are rare in the southeast. Submerged rock also provides cover for many fishes and invertebrates.
However, hardened structures designed for shoreline and channel protection also disrupt natural processes of sand movement along beaches and can contribute significantly to beach erosion. Seawalls and bulkheads in inland waterways can protect the immediate shoreline while potentially exacerbating erosion of the nearby, unprotected shoreline. Such structures also interfere with the nesting of sea turtles either by totally displacing nesting sites or by rendering them more susceptible to flooding.
Moderate Priority: Unranked:
Purple Sandpiper Gag, Lined Seahorse, Florida Stone Crab
General Condition of Habitats
Much of the South Carolina coastal zone has been adversely affected by human population growth and associated development. By the early 1990’s, about 50 percent of the total United States’ human population lived in coastal areas (Moore et al. 1995), and the trend of concentrated growth along coasts is expected to continue into the next century (Cullitan et al. 1990). About 88 miles (48.6 percent) of South Carolina’s beachfront is currently affected by development (Kana 1988). The high concentration of human population growth and development in the coastal zone has fragmented forests and reduced other valuable habitats, such as shrub thickets and isolated wetlands. The vast majority of protected coastal zone holdings are in two regions, the ACE Basin and the Cape Romain- McClellanville area.
Non-native plants colonize both terrestrial and wetland habitats. Such species can dominate or displace native vegetation and can occur in nearly single-species colonies or stands that present a lowered structural diversity and poor wildlife habitat. Both tidal low-salinity marshes and wetlands and littoral (shallow water) areas in ponds and impoundments can be densely covered in waterthyme (Hydrilla verticillata) or common reed (Phragmites communis). Dense colonies of these plants may restrict flows and capture sediment, thereby increasing the rate of eutrophication and contributing to low dissolved oxygen (DO) (McCann et al. 1996; Aulbach- Smith and deKozlowski 1996). Forested wetlands and coastal forests with damp (hydric or