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Article: Facilitating corals in an early Silurian deep-water assemblage

Palaeontology - Vol. 64 - Cover Image
Publication: Palaeontology
Volume: 64
Part: 3
Publication Date: May 2021
Page(s): 359 370
Author(s): Alavya Dhungana, and Emily G. Mitchell
Addition Information

How to Cite

DHUNGANA, A., MITCHELL, E.G. 2021. . Palaeontology, 64, 3, 359-370. DOI: /doi/10.1111/pala.12527

Author Information

  • Alavya Dhungana - Department of Earth Sciences Durham University South Road Durham UK
  • Emily G. Mitchell - Department of Zoology University of Cambridge Downing Street Cambridge UK

Publication History

  • Issue published online: 19 April 2021
  • Manuscript Accepted: 15 December 2020
  • Manuscript Received: 20 July 2020

Funded By

Palaeontological Association Sylvester-Bradley. Grant Number: PA-SB201802
Worts Travelling Scholars Fund
Cowper-Reed Palaeontology fund
Natural Environment Research Council. Grant Number: 627 NE/P002412/1
Independent Research Fellowship. Grant Number: NE/S014756/1

Online Version Hosted By

Wiley Online Library (Open Access)
Get Article: Wiley Online Library [Open Access]


Corals are powerful ecosystem engineers and can form reef communities with extraordinary biodiversity through time. Understanding the processes underlying the spatial distribution of corals allows us to identify the key biological and physical processes that structure coral communities and how these processes and interactions have evolved. However, few spatial ecology studies have been conducted on coral assemblages in the fossil record. Here we use spatial point process analysis (SPPA) to investigate the ecological interactions of an in situ tabulate and rugose coral community (n = 199), preserved under volcanic ash in the Silurian of Ireland. SPPA is able to identify many different sorts of interactions including dispersal limitation and competition within and between taxa. Our SPPA found that the spatial distribution of rugose corals were best modelled by Thomas clusters (pd = 0.834), indicating a single dispersal episode and that the tabulate corals were best modelled by double Thomas clusters (pd = 0.820), indicating two dispersal episodes. Further, the bivariate distribution was best modelled by linked double clusters (pd = 0.970), giving significant evidence of facilitation between the tabulate and rugose populations, and identifying the facilitators in this community to be the tabulate corals. This interaction could be an important ecological driver for enabling the aggregation of sessile organisms over long temporal periods and facilitation may help to explain trends in reef diversity and abundance during the Ordovician biodiversification and in the early Silurian.


We thank Alex Liu for initial encouragement with project. Thanks also to Trish Walsh at the Petersburg Outdoor Education Centre in Clobur, Galway, Charlotte Kenchington for assistance during fieldwork and to Dave Harper for useful discussions. Research and fieldwork was supported by a Palaeontological Association Sylvester-Bradley grant (PA-SB201802 to AD), Worts Travelling Scholars Fund and the Cowper-Reed Palaeontology fund (Dept. Earth Sciences, Cambridge) to AD and the Natural Environment Research Council (grant numbers 627 NE/P002412/1 and Independent Research Fellowship NE/S014756/1 to EGM). We are grateful for the comments made by the two anonymous referees, who helped improve the manuscript.

    Author contributions

    AD first conceived the project. AD and EGM collected the field data. AD performed the analyses. Both authors discussed results and prepared the manuscript.

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