Invasion
Invasion Description
1st Record: NC/South Creek, Pamlico River (Tenore 1968)
Geographic Extent
NC/South Creek, Pamlico River (Tenore 1968; Foltz et al. 1995)
Vectors
| Level | Vector |
|---|---|
| Alternate | Ballast Water |
| Alternate | Oyster Accidental |
| Alternate | Canal |
Regional Impacts
| Ecological Impact | Habitat Change | |
| Habitat Change - Survivorship of the native bivalves Mya arenaria and Macoma balthica was increased in the presence of R. cuneata, but empty shells had similar effects (or greater in M. arenaria) as live clams, indicating that the shells of R. cuneata were providing a physical refuge (Skilleter 1994). The seagrass Ruppia maritima (Widgeon Grass), when present, apparently removed this protective effect, perhaps by interfering with burrowing, or by attracting predators (Skilleter 1994). | ||
| Ecological Impact | Competition | |
| Competition - Effects of R. cuneata on the native clams Mya arenaria (Softshell Clams) and Macoma balthica (Baltic Clams) are complex and subtle. Competition for food is likely; since suspension feeders can deplete plankton in the immediate vicinity. Macoma balthica, in the presence of R. cuneata switched to deposit feeding, resulting in increased rates of partial predation (siphons nipped) (Skilleter and Peterson 1994). This results in energetic costs of regeneration and could slow growth. These effects are apparently partly offset by structural refuges provided by R. cuneata (Skilleter 1994). | ||