Coupling coexistence theory to field experiments: new advancements for community and invasion ecology

Abstract

Explanations for the maintenance of the wide diversity of life have been centered on relate species differences to the processes enabling coexistence. Classic niche theory assumes that coexistence is determined by niche differences. Recent theoretical advances are suggesting instead that niche differences only tend to stabilize coexistence between competitors and the outcome species interactions depends on how stabilizing niche differences are promoted relatively to the fitness differences that favor competitive exclusion. Using different sources of species differences and a model describing population dynamics of competing annual plant species, this talk will present the results of three field experiments. The first experiment testing Darwin’s hypothesis that closely related species tends to compete more strongly than distant relatives will show the reasons why phylogeny is a poor predictor of competitive outcomes. The second experiment testing the limiting similarity hypothesis will show the multidimensional trait nature of species niche differences. The third experiment will show how phenological differences promote invasion success and biotic resistance. Present limitations and future approaches taking into account spatio-temporal variability will be also discussed.