Range shifts and species diversity in marine ecosystem engineers: patterns and predictions for European sedimentary habitats

Authors

  • Sarah K. Berke,

    Corresponding author
    1. University of South Carolina, Department of Biological Sciences, 715 Sumter Street, Columbia, SC 29208, USA,
    2. Smithsonian Environmental Research Center, PO Box 28, Edgewater, MD 21037, USA,
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  • Andrew R. Mahon,

    1. Biological Sciences Department, 101 Rouse Blvd, Auburn University, Auburn, AL 36849, USA,
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  • Fernando P. Lima,

    1. University of South Carolina, Department of Biological Sciences, 715 Sumter Street, Columbia, SC 29208, USA,
    2. CIBIO, Centro de Investigação em Biodiversidade e Recursos Genéticos, Campus Agrário de Vairão, 4485-661 Vairão, Portugal
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  • Kenneth M. Halanych,

    1. Biological Sciences Department, 101 Rouse Blvd, Auburn University, Auburn, AL 36849, USA,
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  • David S. Wethey,

    1. University of South Carolina, Department of Biological Sciences, 715 Sumter Street, Columbia, SC 29208, USA,
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  • Sarah A. Woodin

    1. University of South Carolina, Department of Biological Sciences, 715 Sumter Street, Columbia, SC 29208, USA,
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Sarah K. Berke, University of South Carolina, Department of Biological Sciences, 715 Sumter Street, Columbia, SC 29208, USA.
E-mail: skberke@gmail.com

ABSTRACT

Aim  Ecosystem engineering polychaetes in the genus Diopatra are undergoing range shifts in western Europe. Here we: (1) assess the species diversity underlying these shifts; (2) link biogeographic patterns to sea surface temperature patterns; and (3) predict possible ecosystem-level outcomes of Diopatra's northward expansion.

Location  Western Europe.

Methods  We use molecular phylogenetic and morphological evidence to assess species diversity and biogeographic ranges. Using regression tree analyses, we assess thermal limits for two Diopatra species. We compare biogeographic patterns with historical sea surface temperature patterns to draw links between range shifts and climate change. Finally, we review published data to predict potential ecological changes as Diopatra invades new habitats.

Results  The native Diopatra neapolitana range has contracted 130 km to the south. A cryptogenic species, Diopatra sp. A, has extended the northern limit of the genus 350 km to the southern Brittany Peninsula. Both shifts can be explained by historical sea surface temperature anomalies. The Diopatra sp. A expansion is predicted to continue into the English Channel and the North Sea, introducing large tube structures to sheltered sedimentary habitats that currently lack such structures.

Main conclusions  As climate change intensifies, the sediment-stabilizing Diopatra sp. A will invade habitats dominated by the bioturbating lugworm Arenicola marina. The resulting interaction between functionally different ecosystem engineers will probably cause ecological changes in northern European coastal waters. Existing data for Diopatra species and arenicolids suggest that the diversity and biomass of macroalgae, vascular plants, infauna and epibenthic fauna may increase, while microbial activity may decrease. Net changes in productivity will depend on the relative rates of these changes.

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