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How similar can co-occurring species be in the presence of competition and ecological drift?

ABSTRACT: If two species live on a single resource, the one with a slight advantage will out-compete the other: complete competitors cannot coexist. This is known as the competitive exclusion principle. If no extinction occurs, it is because evolutionary adaptation to slightly different niches takes place. Therefore, it is widely accepted that ecological communities are assembled by evolutionary differentiation and progressive adaptation of species to different niches. However, some ecologists have recently challenged this classic paradigm highlighting the importance of chance and stochasticity. Using a synthetic framework for community dynamics, here we show that, while deterministic descriptors predict coexistence, species similarity is limited in a more restrictive way in the presence of stochasticity. We analyse the stochastic extinction phenomenon, showing that extinction occurs as competitive overlap increases above a certain threshold well below its deterministic counterpart. We also prove that the extinction threshold cannot be ascribed only to demographic fluctuations around small population sizes. The more restrictive limit to species similarity is, therefore, a consequence of the complex interplay between competitive interactions and ecological drift. As a practical implication, we show that the existence of a stochastic limit to similarity has important consequences in the recovery of fragmented habitats.

SUBMITTER: Capitan JA

PROVIDER: S-EPMC4614473 | biostudies-literature | 2015 Sep

REPOSITORIES: biostudies-literature

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How similar can co-occurring species be in the presence of competition and ecological drift?

Capitán José A JA Cuenda Sara S Alonso David D

Journal of the Royal Society, Interface 20150901 110

If two species live on a single resource, the one with a slight advantage will out-compete the other: complete competitors cannot coexist. This is known as the competitive exclusion principle. If no extinction occurs, it is because evolutionary adaptation to slightly different niches takes place. Therefore, it is widely accepted that ecological communities are assembled by evolutionary differentiation and progressive adaptation of species to different niches. However, some ecologists have recent ...[more]

PMID: 26269234

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How similar can co-occurring species be in the presence of competition and ecological drift?

Publications

How similar can co-occurring species be in the presence of competition and ecological drift?

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