BIOGEOMORPHOLOGY AND LANDSCAPE EVOLUTION - THE PROBLEM OF SCALE

Vegetation may vary continuously and rapidly, while landforms sometimes vary episodically and relatively slowly. This disparity in temporal scales creates scale linkage problems in dealing with landform-vegetation interactions. Four theoretical approaches for coping with these issues are outlined, and illustrated via applications to problems arising from fieldwork on the coastal plain of North Carolina. The first approach, the transient form ratio, is used to determine whether ecosystems and geomorphic environments preserved in Pleistocene stratigraphy represent stable landform-ecosystem combinations which should reflect landform and vegetation responses to sea level rise. The second, the information criterion, is applied to estimate the appropriate time steps for simulation modelling, and appropriate spatial resolutions for field studies, of vegetation effects on soil thickness in coastal plain uplands. The abstracted systems argument, the third approach, is used to show that alluvial sedimentation and floodplain ecological dynamics cannot be considered independently in studies of floodplain system response to post-European settlement. Finally, ratios of relaxation times and durations suggest that changes in upland erosion regimes associated with historical devegetation are best treated as a singular perturbation in the context of Quaternary landscape evolution.