Anthropogenic extinction threats and future loss of evolutionary history in reef corals

Authors

  • Danwei Huang,

    Corresponding author
    1. Scripps Institution of Oceanography, University of California San Diego, California
    Current affiliation:
    1. Department of Geoscience, University of Iowa, Iowa City, IA
    • Department of Biological Sciences, National University of Singapore, Singapore
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  • Kaustuv Roy

    1. Section of Ecology, Behavior and Evolution, University of California San Diego, California
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  • Data Archival Data for this study are available at TreeBASE study ID: S13550 and as supporting information.

Correspondence

Danwei Huang, Department of Biological Sciences, National University of Singapore, Singapore 117543; Tel: +65-6516-6867; Fax: +65-6779-2486; E-mail: huangdanwei@nus.edu.sg

Abstract

Extinction always results in loss of phylogenetic diversity (PD), but phylogenetically selective extinctions have long been thought to disproportionately reduce PD. Recent simulations show that tree shapes also play an important role in determining the magnitude of PD loss, potentially offsetting the effects of clustered extinctions. While patterns of PD loss under different extinction scenarios are becoming well characterized in model phylogenies, analyses of real clades that often have unbalanced tree shapes remain scarce, particularly for marine organisms. Here, we use a fossil-calibrated phylogeny of all living scleractinian reef corals in conjunction with IUCN data on extinction vulnerabilities to quantify how loss of species in different threat categories will affect the PD of this group. Our analyses reveal that predicted PD loss in corals varies substantially among different threats, with extinctions due to bleaching and disease having the largest negative effects on PD. In general, more phylogenetically clustered extinctions lead to larger losses of PD in corals, but there are notable exceptions; extinction of rare corals from distantly-related old and unique lineages can also result in substantial PD loss. Thus our results show that loss of PD in reef corals is dependent on both tree shape and the nature of extinction threats.

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