Empirical data for several ecological systems suggest that how
resource availability scales with patch geometry may influence the outcome of
species interactions. To study this process, we assume a pseudoequilibrium
to reduce the dimensionality of a two-consumer-two-resource model in which
different resources are available in the interior of a patch versus at the edge.
We analyze the resulting two species competition model to understand how the
outcome of competition between consumers changes as the size of the patch
changes, paying particular attention to the differential scaling of interior and
edge-linked allochthonous resources as a function of patch size. We characterize
conditions on patch size and parameters under which competitive exclusion,
coexistence, and a reversal in competitive dominance occur. We find that
the degree of exclusivity in the use of edge versus interior habitats influences
the potential for transitions in competitive outcomes, but that differences in
resource quality between interior and edge habitats can, depending on the
scenario, have either qualitative or quantitative influences on the transitions.
The work highlights the importance of patch size to understanding species
interactions and demonstrates that competitive dominance can be a scale-
Mathematics Subject Classification: 92D40, 34D20.