Extent and Composition of Open Coastal Sandplain Plant Communities of the Cape Cod National Seashore

Abstract

Coastal sandplain heathlands and grasslands of the northeastern United States are globally rare habitat types that support a unique assemblage of plants and animals. This habitat is rapidly disappearing due to plant succession following cessation of land use, and coastal processes. I used interpretation of historical maps, aerial photography, GIS, and analysis of field data to examine vegetation dynamics and the impact of historic land use and coastal processes on the current extent and composition of coastal sandplain plant communities found within the Cape Cod National Seashore (CCNS). Currently, one third (244 ha) of the coastal heathland and grassland habitat present at the inception of CCNS in 1961 still remains. Analysis and interpretation of time series aerial photography of sites (n=3) impacted by extreme land use shows that these areas follow a ~35-year successional path from bare mineral soil to predominately Pinus rigida shrubland or forest. Current extent and composition of coastal heathland is primarily determined by two factors: how recent and intense was historical land use at a site; and the influence of coastal processes, such as salt spray and sand deposition. Any influence by edaphic factors is likely confounded by past land use.