Document: MAR-3-65-7

Linking biogeochemical function and community dynamics on forest edges.

CADENASSO, M.L.*, S.T.A.PICKETT and K.C.WEATHERS

Institute of Ecosystem Studies, Millbrook, NY 12545, U.S.A. ¹

Abstract:
Research on forest edges has been primarily descriptive and has focused on two distinct topics - population and community level processes and atmospheric fluxes. We demonstrate the lack of overlap between the two literatures and present a conceptual model to: 1) provide a framework for linking biogeochemical processes and biotic dynamics and 2) synthesize data from a field experiment designed to quantify the link between edge structure and function. Central to this model is the influence of edge structure on the below canopy flux of important nutrients such as nitrogen. We found that edges receive, on average, 50% more total inorganic nitrogen below the canopy than do adjacent forest interiors. We also quantified the influence of edge structure on two biotic fluxes - the flux of seeds and of seedling herbivores - by experimentally creating two contrasting edge structures. We demonstrated that an intact edge functions as a physical barrier to wind dispersed seeds, thereby limiting the flux of seeds into the forest, and that damage to tree seedlings by herbivores is greater on intact edges. Potential links and feedbacks among biogeochemical processes and biotic dynamics on edges are illustrated in the model to suggest how the below-canopy nutrient flux may cascade through the community and, ultimately, influence seedling regeneration.

Keywords: forest edges, biogeochemical fluxes, herbivory, seed dispersal, conceptual model

This abstract is being presented at: 10:30 AM in session:
Poster Session #5: Landscape Ecology.