Non-alluvial wetland community types of the southern Appalachian region of the Carolinas

Background/Question/Methods

The ecological uniqueness and conservation value of southern Appalachian non-alluvial wetlands is well documented. However, past understanding of these montane, peat-forming wetlands has been based primarily on qualitative data, and there has been no comprehensive quantitative analysis, classification, or description of these communities, nor has there been any comprehensive analysis of their distribution and compositional variation. We inventoried over 100 non-alluvial wetlands distributed to represent the range of variation across the southern Appalachian region of North and South Carolina. Communities were delimited using hierarchical cluster analysis, and non-metric multidimensional scaling was subsequently used to help differentiate and describe groups identified by the cluster analysis.

Results/Conclusions

We identify twenty-three vegetation groups ranging in composition from forested wetlands, through seeps and shrub-dominated wetlands, to open sedge-sphagnum wetlands. Currently, twenty-eight non-alluvial wetland community types recognized by the U.S. National Vegetation Classification are reported to occur in North Carolina or nearby in adjacent states, and the North Carolina Natural Heritage Program recognizes eighteen non-alluvial wetland community types within the state. Although some of the twenty-three groups we recognize fit well within currently established community types, others deviate sharply from established types, pointing to a need for definition of new types and/or significant refinement of those currently recognized. The large number of previously recognized vegetation types and their seeming lack of fit with our quantitatively defined vegetation groups underscores the risks involved in subjective delineation of community types in systems that are insular in character and have considerable spatial variation resulting from chance events of establishment and survival.