Appalachian - Acadian Basin Swamp EcosystemState Rank: S4
Topographic basins with only a small to mid-sized stream as an outlet, mostly to entirely forested, and with minimal peat accumulation. Swamps that occur immediately associated with a lake or larger stream are included under lakeshore and streamshore ecosystems; forested basins with closed drainage and peat accumulation are included under peatland ecosystems. Distributed statewide except for extreme southern Maine, where basin swamps are distinguished as a separate type, Coastal Plain Basin Swamp Ecosystem, characterized by assemblages with more southerly affinities. First-order or second-order streams may drain the swamp. Pockets without trees (shrub swamp or short graminoid marsh) may occur within the basin swamp.