vacant

A vacant niche or empty niche is an ecological niche in a particular ecosystem that is not occupied by a particular species. The issue of what exactly defines a vacant niche and whether they exist in ecosystems is controversial. The subject is intimately tied into a much broader debate on whether ecosystems can reach equilibrium, where they could theoretically become maximally saturated with species. Given that saturation is a measure of the number of species per resource axis per ecosystem, the question becomes: is it useful to define unused resource clusters as niche 'vacancies'?

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