MEPS 308:17-25 (2006)  -  doi:10.3354/meps308017

Larval dispersal reveals regional sources and sinks in the Great Barrier Reef

Michael Bode1,3,*, Lance Bode1, Paul R. Armsworth2,4

1School of Mathematical and Physical Sciences, James Cook University, Townsville 4811, Queensland, Australia
2Department of Biological Sciences, Stanford University, Stanford, California 94305, USA
3Present address: Department of Mathematics, University of Queensland, Brisbane 4072, Queensland, Australia
4Present address: Department of Animal and Plant Sciences, University of Sheffield, Sheffield S10 2TN, UK

ABSTRACT: We analysed simulated connectivity patterns for reef fish larvae in the Cairns section of the Great Barrier Reef, and identified 2 key subregions that exhibit regional scale source–sink dynamics. The source and sink were separated latitudinally by a boundary at 16.1°S, with the source subregion lying to the north. Larval transport between the 2 subregions was predominantly unidirectional, from north to south. Only a few local populations, described here as ‘gateway reefs’, were able to transport larvae from the sink subregion to the source subregion and thus maintain the connectedness of the metapopulation. The northern subregion was able to persist without external larval supply, but when conditions were recruitment limited, the southern subregion depended on larval supply from the north to persist. The relative autonomy of the northern subregion, and its importance in sustaining the southern subregion, will influence the effectiveness of conservation efforts.

KEY WORDS: Larval dispersal · Source–sink · Coral reef fish · Metapopulation dynamics

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