Competition at community boundaries: mechanisms of vegetation structure in a dune-slack complex

A re-examination of the distribution of the dominant species in a series of dune and slack communities after an interval of 24 years revealed varying amounts of movement in the boundaries between the different vegetation types. Some boundaries showed no measurable differences in location while others had changed significantly. The most stable boundary was between the Carex arenaria heath vegetation of the dune tops and the Filipendula ulmaria-dominated community of the adjacent dune slack. This boundary coincided with the maximum winter flood-line which has remained stable despite increased flooding, as excess water decants into drier slacks to seaward (...)