Evidence of limiting similarity revealed using a conservative assessment of coexistence

Abstract

AbstractThe concept of limiting similarity is important in ecology because it encapsulates the expectation under niche theory that differences among species are fundamental to coexistence. A growing body of research has tested for evidence of limiting similarity, but only a small number of studies have produced support. Here, using relevant field data, we highlight one possible explanation for the paucity of support for limiting similarity. We test whether coexisting plant species that share bees as pollinators flower asynchronously, a form of temporal niche separation consistent with limiting similarity. Our results provide evidence of limiting similarity, adding to the small collection of null modeling studies that have thus far done so. Our work also provides evidence that temporal niche variation may be an important niche axis that broadly contributes to species coexistence. Finally, we demonstrate that a more conservative assessment of coexistence that includes only individual plants that have achieved reproduction, is consequential in whether we find evidence of significant flowering asynchrony in this study. We conclude that the conservative approach to assessing coexistence that we present here can reduce noise in coexistence data, improving our power to test for evidence consistent with limiting similarity. Using this approach may or may not result in an increase in evidence supporting limiting similarity; however, it will certainly give researchers more confidence that they have not missed existing evidence of limiting similarity.