Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Article
  • Published:

The population sizes and global extinction risk of reef-building coral species at biogeographic scales

Nature Ecology & Evolution volume 5, pages 663–669 (2021)Cite this article

Subjects

Matters Arising to this article was published on 14 February 2022

An Author Correction to this article was published on 16 March 2021

This article has been updated

Abstract

Knowledge of a species’ abundance is critically important for assessing its risk of extinction, but for the vast majority of wild animal and plant species such data are scarce at biogeographic scales. Here, we estimate the total number of reef-building corals and the population sizes of more than 300 individual species on reefs spanning the Pacific Ocean biodiversity gradient, from Indonesia to French Polynesia. Our analysis suggests that approximately half a trillion corals (0.3 × 1012–0.8 × 1012) inhabit these coral reefs, similar to the number of trees in the Amazon. Two-thirds of the examined species have population sizes exceeding 100 million colonies, and one-fifth of the species even have population sizes greater than 1 billion colonies. Our findings suggest that, while local depletions pose imminent threats that can have ecologically devastating impacts to coral reefs, the global extinction risk of most coral species is lower than previously estimated.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: The Indo-Pacific biodiversity gradient and the locations where coral abundance and reef habitat data were collected.
Fig. 2: Taxonomic and morphological composition of the Pacific coral fauna.
Fig. 3: The population sizes of Indo-Pacific coral species and their conservation status.
Fig. 4: Correlation between numerical abundance and the area occupied by each species.

Similar content being viewed by others

Data availability

Data files for statistical analyses are available from the Tropical Data Hub (https://tropicaldatahub.org/) at https://doi.org/10.25903/cemc-3512.

Code availability

Computer code for statistical analyses is available from the Tropical Data Hub (https://tropicaldatahub.org/) at https://doi.org/10.25903/cemc-3512.

Change history

References

  1. Wilkinson, C. Status of Coral Reefs of the World: 2008 (Global Coral Reef Monitoring Network and Reef and Rainforest Research Centre, 2008).

  2. Jackson, J. B. C., Donovan, M. K., Cramer, K. L. & Lam, V. V. Status and Trends of Caribbean Coral Reefs: 1970–2012 (Global Coral Reef Monitoring Network, 2014).

  3. Eakin, C. M. et al. Caribbean corals in crisis: record thermal stress, bleaching, and mortality in 2005. PLoS ONE 5, e13969 (2010).

    Article  PubMed  PubMed Central  Google Scholar 

  4. Baker, A. C., Glynn, P. W. & Riegl, B. Climate change and coral reef bleaching: an ecological assessment of long-term impacts, recovery trends and future outlook. Estuar. Coast. Shelf Sci. 80, 435–471 (2008).

    Article  Google Scholar 

  5. Hughes, T. P. et al. Global warming transforms coral reef assemblages. Nature 556, 492–496 (2018).

    Article  CAS  PubMed  Google Scholar 

  6. Hughes, T. P. et al. Spatial and temporal patterns of mass bleaching of corals in the Anthropocene. Science 359, 80–83 (2018).

    Article  CAS  PubMed  Google Scholar 

  7. De’ath, G., Fabricius, K. E., Sweatman, H. & Puotinen, M. The 27-year decline of coral cover on the Great Barrier Reef and its causes. Proc. Natl Acad. Sci. USA 109, 17995–17999 (2012).

    Article  PubMed  PubMed Central  Google Scholar 

  8. Gardner, T. A. Long-term region-wide declines in Caribbean corals. Science 301, 958–960 (2003).

    Article  CAS  PubMed  Google Scholar 

  9. Carpenter, K. E. et al. One-third of reef-building corals face elevated extinction risk from climate change and local impacts. Science 321, 560–563 (2008).

    Article  CAS  PubMed  Google Scholar 

  10. ter Steege, H. et al. Estimating the global conservation status of more than 15,000 Amazonian tree species. Sci. Adv. 1, e1500936 (2015).

    Article  PubMed  PubMed Central  Google Scholar 

  11. Fauset, S. et al. Hyperdominance in Amazonian forest carbon cycling. Nat. Commun. 6, 6857 (2015).

    Article  CAS  PubMed  Google Scholar 

  12. Crowther, T. W. et al. Mapping tree density at a global scale. Nature 525, 201–205 (2015).

    Article  CAS  PubMed  Google Scholar 

  13. Connell, J., Hughes, T. & Wallace, C. A 30-year study of coral abundance, recruitment, and disturbance at several scales in space and time. Ecol. Monogr. 67, 461–488 (1997).

    Article  Google Scholar 

  14. Hughes, T. P. & Jackson, J. B. C. Population dynamics and life histories of foliaceous corals. Ecol. Monogr. 55, 141–166 (1985).

    Article  Google Scholar 

  15. ter Steege, H. et al. Hyperdominance in the Amazonian tree flora. Science 342, 1243092 (2013).

    Article  PubMed  Google Scholar 

  16. Gaston, K. J. & Blackburn, T. M. How many birds are there? Biodivers. Conserv. 6, 615–625 (1997).

    Article  Google Scholar 

  17. Kerry, J. T. & Bellwood, D. R. Do tabular corals constitute keystone structures for fishes on coral reefs? Coral Reefs 34, 41–50 (2015).

    Article  Google Scholar 

  18. Connolly, S. R., Hughes, T. P., Bellwood, D. R. & Karlson, R. H. Community structure of corals and reef fishes at multiple scales. Science 309, 1363–1365 (2005).

    Article  CAS  PubMed  Google Scholar 

  19. Connolly, S. R., Hughes, T. P. & Bellwood, D. R. A unified model explains commonness and rarity on coral reefs. Ecol. Lett. 20, 477–486 (2017).

    Article  PubMed  Google Scholar 

  20. Hubbell, S. P. Estimating the global number of tropical tree species, and Fisher’s paradox. Proc. Natl Acad. Sci. USA 112, 7343–7344 (2015).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. Hughes, T. P., Bellwood, D. R. & Connolly, S. R. Biodiversity hotspots, centres of endemicity, and the conservation of coral reefs. Ecol. Lett. 5, 775–784 (2002).

    Article  Google Scholar 

  22. Hughes, T. P., Bellwood, D. R., Connolly, S. R. & Cornell, H. V. Double jeopardy and global extinction risk in corals and reef fishes. Curr. Biol. 24, 2946–2951 (2014).

    Article  CAS  PubMed  Google Scholar 

  23. Kinlan, B. P. & Gaines, S. D. Propagule dispersal in marine and terrestrial environments: a community perspective. Ecology 84, 2007–2020 (2003).

    Article  Google Scholar 

  24. Hull, P. M., Darroch, S. A. F. & Erwin, D. H. Rarity in mass extinctions and the future of ecosystems. Nature 528, 345–351 (2015).

    Article  CAS  PubMed  Google Scholar 

  25. Cardoso, P., Borges, P. A. V., Triantis, K. A., Ferrández, M. A. & Martín, J. L. Adapting the IUCN Red List criteria for invertebrates. Biol. Conserv. 144, 2432–2440 (2011).

    Article  Google Scholar 

  26. Cardoso, P., Borges, P. A. V., Triantis, K. A., Ferrández, M. A. & Martín, J. L. The underrepresentation and misrepresentation of invertebrates in the IUCN Red List. Biol. Conserv. 149, 147–148 (2012).

    Article  Google Scholar 

  27. Estes, J. A., Duggins, D. O. & Rathbun, G. B. The ecology of extinctions in kelp forest communities. Conserv. Biol. 3, 252–264 (1989).

    Article  Google Scholar 

  28. Oliver, J. & Babcock, R. Aspects of the fertilization ecology of broadcast spawning corals: sperm dilution effects and in situ measurements of fertilization. Biol. Bull. 183, 409–417 (1992).

    Article  CAS  PubMed  Google Scholar 

  29. Knowlton, N., Lang, J. C. & Keller, B. D. Case study of natural population collapse: post-hurricane predation on Jamaican staghorn corals. Smithson. Contrib. Mar. Sci. 31, 1–25 (1990).

    Google Scholar 

  30. Gaston, K. J. & Fuller, R. A. Commonness, population depletion and conservation biology. Trends Ecol. Evol. 23, 14–19 (2008).

    Article  PubMed  Google Scholar 

  31. Säterberg, T., Sellman, S. & Ebenman, B. High frequency of functional extinctions in ecological networks. Nature 499, 468–470 (2013).

    Article  PubMed  Google Scholar 

  32. Pratchett, M. S. Dietary overlap among coral-feeding butterflyfishes (Chaetodontidae) at Lizard Island, northern Great Barrier Reef. Mar. Biol. 148, 373–382 (2005).

    Article  Google Scholar 

  33. Huang, D., Licuanan, W. Y., Baird, A. H. & Fukami, H. Cleaning up the ‘Bigmessidae’: molecular phylogeny of scleractinian corals from Faviidae, Merulinidae, Pectiniidae and Trachyphylliidae. BMC Evol. Biol. 11, 37 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  34. Knowlton, N. & Jackson, J. B. C. New taxonomy and niche partitioning on coral reefs: jack of all trades or master of some? Trends Ecol. Evol. 9, 7–9 (1994).

    Article  CAS  PubMed  Google Scholar 

  35. Gilpin, M. E. & Soulé, M. E. in Conservation Biology: The Science of Scarcity and Diversity (ed, Soulé, M. E.) 19–34 (Sinauer Associates, 1986).

  36. Bak, R. P. M. & Meesters, E. H. Population structure as a response of coral communities to global change. Am. Zool. 39, 56–65 (1999).

    Article  Google Scholar 

  37. McClanahan, T. R., Ateweberhan, M. & Omukoto, J. Long-term changes in coral colony size distributions on Kenyan reefs under different management regimes and across the 1998 bleaching event. Mar. Biol. 153, 755–768 (2008).

    Article  Google Scholar 

  38. Riegl, B. M., Bruckner, A. W., Rowlands, G. P., Purkis, S. J. & Renaud, P. Red Sea coral reef trajectories over 2 decades suggest increasing community homogenization and decline in coral size. PLoS ONE 7, e38396 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  39. Hughes, T. P. et al. Coral reefs in the Anthropocene. Nature 546, 82–90 (2017).

    Article  CAS  PubMed  Google Scholar 

  40. Global Distribution of Coral Reefs (UNEP-WCMC, WorldFish Centre, WRI & TNC, 2018); https://data.unep-wcmc.org/datasets/

  41. Bruno, J. F. & Valdivia, A. Coral reef degradation is not correlated with local human population density. Sci. Rep. 6, 29778 (2016).

  42. Bruno, J. Data from: Coral reef degradation is not correlated with local human population density. Dryad Digital Repository https://doi.org/10.5061/dryad.48r68 (2016).

  43. Karlson, R. H., Cornell, H. V. & Hughes, T. P. Coral communities are regionally enriched along an oceanic biodiversity gradient. Nature 429, 867–870 (2004).

    Article  CAS  PubMed  Google Scholar 

  44. Cornell, H. V., Karlson, R. H. & Hughes, T. P. Scale-dependent variation in coral community similarity across sites, islands, and island groups. Ecology 88, 1707–1715 (2007).

    Article  PubMed  Google Scholar 

  45. Cornell, H. V., Karlson, R. H. & Hughes, T. P. Local-regional species richness relationships are linear at very small to large scales in west-central Pacific corals. Coral Reefs 27, 145–151 (2008).

    Article  Google Scholar 

  46. Connolly, S. R., Dornelas, M., Bellwood, D. R. & Hughes, T. P. Testing species abundance models: a new bootstrap approach applied to Indo-Pacific coral reefs. Ecology 90, 3138–3149 (2009).

    Article  PubMed  Google Scholar 

  47. Reef Habitat Maps (NOAA-NCCOS, accessed 10 November 2017); https://products.coastalscience.noaa.gov/collections/benthic/default.aspx

  48. Purkis, S. J. et al. High-resolution habitat and bathymetry maps for 65,000 sq. km of Earth’s remotest coral reefs. Coral Reefs 38, 467–488 (2019).

    Article  Google Scholar 

  49. Roelfsema, C., Phinn, S., Jupiter, S., Comley, J. & Albert, S. Mapping coral reefs at reef to reef-system scales, 10s–1000s km2, using object-based image analysis. Int. J. Remote Sens. 34, 6367–6388 (2013).

    Article  Google Scholar 

  50. Bürkner, P.-C. brms: an R package for Bayesian multilevel models using Stan. J. Stat. Softw. 80, 1–28 (2017).

    Article  Google Scholar 

  51. Warton, D. I. & Hui, F. K. C. The arcsine is asinine: the analysis of proportions in ecology. Ecology 92, 3–10 (2011).

    Article  PubMed  Google Scholar 

  52. Marsh, L. M., Bradbury, R. H. & Reichelt, R. E. Determination of the physical parameters of coral distributions using line transect data. Coral Reefs 2, 175–180 (1984).

    Google Scholar 

  53. Hughes, T. P. Population dynamics based on individual size rather than age: a general model with a reef coral example. Am. Nat. 123, 778–795 (1984).

    Article  Google Scholar 

  54. Hall, V. R. & Hughes, T. P. Reproductive strategies of modular organisms: comparative studies of reef-building corals. Ecology 77, 950–963 (1996).

    Article  Google Scholar 

  55. Hughes, T. P., Connolly, S. R. & Keith, S. A. Geographic ranges of reef corals (Cnidaria: Anthozoa: Scleractinia) in the Indo-Pacific. Ecology 94, 1659 (2013).

    Article  Google Scholar 

  56. Bar-On, Y. M., Phillips, R. & Milo, R. The biomass distribution on Earth. Proc. Natl Acad. Sci. USA 115, 6506–6511 (2018).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  57. van den Hoogen, J. et al. Soil nematode abundance and functional group composition at a global scale. Nature 572, 194–198 (2019).

    Article  PubMed  Google Scholar 

  58. Hubbell, S. P. et al. How many tree species are there in the Amazon and how many of them will go extinct? Proc. Natl Acad. Sci. USA 105, 11498–11504 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. Atkinson, A., Siegel, V., Pakhomov, E. A., Jessopp, M. J. & Loeb, V. A re-appraisal of the total biomass and annual production of Antarctic krill. Deep-Sea Res. I 56, 727–740 (2009).

    Article  Google Scholar 

  60. Current World Population (Worldometer, accessed 13 May 2020); https://www.worldometers.info/world-population/

  61. California Condor Recovery Program: 2017 Annual Population Status (US Fish and Wildlife Service, 2017).

  62. Goodrich, J. M. et al. Panthera tigris. The IUCN Red List of Threatened Species 2015 Report number e.T15955A50659951 (IUCN, 2015).

Download references

Acknowledgements

We thank many individuals for assistance with species identification and field surveys, particularly A. Baird, S. Blake, M. Boyle, H. Cornell, E. Dinsdale, R. Karlson, M. Kaspartov, P. Osmond and J. Wolstenholme. Major funding for this analysis was provided by the Australian Research Council’s Centre of Excellence Program (CE140100020) and a Laureate Fellowship to T.P.H. (FL120100063).

Author information

Authors and Affiliations

  1. ARC Centre of Excellence for Coral Reef Studies, James Cook University, Townsville, Queensland, Australia

    Andreas Dietzel, Michael Bode, Sean R. Connolly & Terry P. Hughes

  2. School of Mathematical Sciences, Queensland University of Technology, Brisbane, Queensland, Australia

    Michael Bode

  3. College of Science and Engineering, James Cook University, Townsville, Queensland, Australia

    Sean R. Connolly

  4. Smithsonian Tropical Research Institute, Balboa, Republic of Panama

    Sean R. Connolly

Authors
  1. Andreas Dietzel
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Michael Bode
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Sean R. Connolly
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Terry P. Hughes
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

T.P.H. led the fieldwork and taxonomic training to collect the species abundance data. A.D., M.B. and T.P.H. developed the study concept and analytical framework. S.R.C. contributed to statistical analyses. A.D. led the writing with contributions from all authors.

Corresponding author

Correspondence to Andreas Dietzel.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Peer review information Nature Ecology & Evolution thanks Hans ter Steege, Robert Steneck and the other, anonymous, reviewer(s) for their contribution to the peer review of this work.

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Supplementary information

Supplementary Information

Supplementary Tables 1–2 and Figs. 1–7.

Reporting Summary

Supplementary Data

Supplementary Data 1: a table listing the abundance of 318 Indo-Pacific coral species by region and habitat type measured as number of intercepts. Supplementary Data 2: a table listing the estimated population sizes of 318 Indo-Pacific coral species and their current IUCN conservation status. Supplementary Data 3: a table listing the locations and sources of 61 compiled reef habitat maps.

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Dietzel, A., Bode, M., Connolly, S.R. et al. The population sizes and global extinction risk of reef-building coral species at biogeographic scales. Nat Ecol Evol 5, 663–669 (2021). https://doi.org/10.1038/s41559-021-01393-4

Download citation

  • Received:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41559-021-01393-4

This article is cited by

Search

Advanced search

Quick links

Nature Briefing Anthropocene

Sign up for the Nature Briefing: Anthropocene newsletter — what matters in anthropocene research, free to your inbox weekly.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing: Anthropocene