Print PageClassical mechanisms which allow coexistence of competing species typically focus on niche differences as a means to weaken interspecific competition relative to intraspecific competition; however, empirical demonstrations of this mechanism have proven difficult. Recently it has been proposed that species-level selection can allow coexistence when the optimal traits for existing in conspecific neighborhoods exhibit a tradeoff with those which are optimal for existing in heterospecific neighborhoods. We formulate a general model of this phenomenon where the coefficients of a Lotka-Volterra competition model are governed by a quantitative trait which is under selection in one species.
Results/Conclusions
We demonstrate that this ‘neighbor-dependent’ selection can stabilize coexistence when it is not otherwise possible; coexistence arises from an intransitive competitive loop, formed by two species and neighbor-dependent selection acting one of the species’ traits. Furthermore, we analyze the general conditions necessary for this outcome to arise. Given recent evidence for evolution on time-scales commensurate with ecological dynamics, selection may be a widespread, fundamentally important mechanism, for achieving species coexistence.
