Testing biodiversity theory using species richness of reef-building corals across a depth gradient.

Testing biodiversity theory using species richness of reef-building corals across a depth gradient. Biol Lett. 2019 Oct 31;15(10):20190493 Authors: Roberts TE, Keith SA, Rahbek C, Bridge TCL, Caley MJ, Baird AH Abstract Natural environmental gradients encompass systematic variation in abiotic factors that can be exploited to test competing explanations of biodiversity patterns. The species-energy (SE) hypothesis attempts to explain species richness gradients as a function of energy availability. However, limited empirical support for SE is often attributed to idiosyncratic, local-scale processes distorting the underlying SE relationship. Meanwhile, studies are also often confounded by factors such as sampling biases, dispersal boundaries and unclear definitions of energy availability. Here, we used spatially structured observations of 8460 colonies of photo-symbiotic reef-building corals and a null-model to test whether energy can explain observed coral species richness over depth. Species richness was left-skewed, hump-shaped and unrelated to energy availability. While local-scale processes were evident, their influence on species richness was insufficient to reconcile observations with model predictions. Therefore, energy availability, either in isolation or in combination with local deterministic processes, was unable to explain coral species richness across depth. Our results demonstrate that local-scale processes do not necessar...
Source: Biology Letters - Category: Biology Authors: Tags: Biol Lett Source Type: research