Patterns of species range evolution in Indo-Pacific reef assemblages reveal the Coral Triangle as a net source of transoceanic diversity.

Sean M Evans,Jennifer Tournois,Caroline Mckenna,Stephen D Simpson,Martin J Genner

doi:10.1098/rsbl.2016.0090

Sean M Evans, Jennifer Tournois + Show 3 more

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https://doi.org/10.1098/rsbl.2016.0090

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Journal: Biology Letters	Publication Date: Jun 1, 2016
Citations: 32	License type: cc-by

Affiliation: University of Bristol, University of Exeter

Abstract

The Coral Triangle in the Indo-Pacific is a region renowned for exceptional marine biodiversity. The area could have acted as a ‘centre of origin’ where speciation has been prolific or a ‘centre of survival’ by providing refuge during major environmental shifts such as sea-level changes. The region could also have acted as a ‘centre of accumulation’ for species with origins outside of the Coral Triangle, owing to it being at a central position between the Indian and Pacific oceans. Here, we investigated support for these hypotheses using population-level DNA sequence-based reconstructions of the range evolution of 45 species (314 populations) of Indo-Pacific reef-associated organisms. Our results show that populations undergoing the most ancient establishment were significantly more likely to be closer to the centre of the Coral Triangle than to peripheral locations. The data are consistent with the Coral Triangle being a net source of coral-reef biodiversity for the Indo-Pacific region, suggesting that the region has acted primarily as a centre of survival, a centre of origin or both. These results provide evidence of how a key location can influence the large-scale distributions of biodiversity over evolutionary timescales.

Highlights

Understanding the causes of spatial distributions of biodiversity is a fundamental goal of contemporary ecology and evolutionary biology
The Coral Triangle, otherwise known as the Indo-Australian Archipelago, is a region of the Indo-Pacific characterized by coral-rich shelf-seas and a high diversity of reef-associated organisms [3], including over 2000 species of coral-reef-associated fishes [4]
There was a consistent pattern of the populations undergoing earlier establishment being closest to the estimated centre of the Coral Triangle (30 of 45 species, binomial test, p 1⁄4 0.010; figure 2a, electronic supplementary material, table S2)

Summary

Introduction

Understanding the causes of spatial distributions of biodiversity is a fundamental goal of contemporary ecology and evolutionary biology. Global-scale analyses of marine diversity show that some locations are unusually rich in species [1] and knowledge of the underlying causes of such patterns can have implications for conservation and sustainable exploitation in a changing world [2]. The Coral Triangle, otherwise known as the Indo-Australian Archipelago, is a region of the Indo-Pacific characterized by coral-rich shelf-seas and a high diversity of reef-associated organisms [3], including over 2000 species of coral-reef-associated fishes [4]. We can largely reject the concept of panmixia within reef-associated species across the region and instead we can consider the relative ages of metapopulations within a species. This provides a useful opportunity to investigate

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