Modelling dispersal and connectivity of broadcast spawning corals at the global scale

S. Wood, C. B. Paris, A. Ridgwell, E. J. Hendy

Research output: Contribution to journalArticlepeer-review

87 Scopus citations

Abstract

Aim: We develop the first global model of connectivity for a generic broadcast spawning coral, and compare the results to connectivity estimates from genetic studies, general biogeographic patterns and theories. We also derive various 'connectivity indices' describing relative isolation and source potential between locations. Location: Modelled oceans 47°S-47°N. Methods: Dispersal of model coral 'larvae' was simulated over 8 years using an individual-based biophysical dispersal model driven by 1/12°-resolution surface ocean current data and incorporating individual trait variability (e.g. a phased pre-competency period). Source and arrival locations of modelled larvae on suitable reef habitat gave standardized dispersal paths and relative levels of connectivity. Results: In the model c. 50% of connections occurred within 50-100km, with rarer dispersal between regions linking entire oceans in a 'stepping stone' fashion. The central Pacific was an almost complete barrier to dispersal, only rarely breached westward from the Galapagos to Marquesas Islands. Areas showing strong isolation also included Hawaii, Easter Island, the Red Sea and the eastern Atlantic. The Indo-West Pacific and Great Barrier Reef showed the highest levels of connectivity, with secondary peaks in the western Indian Ocean, corresponding to areas of enriched coral diversity. The central Indo-Pacific diversity hotspot was overall a greater source than sink for dispersal. Conclusions: This study provides a global view of connectivity that complements genetic and biogeographic work as well as providing a number of novel findings relevant to biogeographic theories (e.g. the central Indo-Pacific as a dispersal source; Johnston Atoll as the sole 'stepping-stone' into Hawaii). Discrepancies with proposed connectivity patterns (e.g. one-way, westward, connectivity across the central Pacific) present hypotheses for future research. The model represents an effective tool for exploring the factors controlling connectivity on this scale and the effects of climate change on future connectivity, and will also aid predictions of future reef distributions.

Original languageEnglish (US)
Pages (from-to)1-11
Number of pages11
JournalGlobal Ecology and Biogeography
Volume23
Issue number1
DOIs
StatePublished - Jan 2014

Keywords

  • 'Coral Triangle'
  • Biophysical modelling
  • Connectivity
  • Coral biogeography
  • Coral reefs
  • East Pacific Barrier
  • Hawaii
  • Indian Ocean
  • Larval dispersal
  • Tropical eastern Pacific

ASJC Scopus subject areas

  • Global and Planetary Change
  • Ecology, Evolution, Behavior and Systematics
  • Ecology

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