Ocean warming impacts on coral larval dispersal patterns and connectivity

Abstract

Climate change will alter many aspects of the ecology of organisms, including dispersal patterns and population connectivity. Understanding future dispersal patterns of key ecosystem species, such as corals, is essential to predict future species distributions, potential for adaptation, and to design effective networks of protected areas that could maximize coral reefs’ chances of persistence. In marine environments, dispersal is often accomplished by larvae, and at higher temperatures, larvae develop faster, but suffer higher mortality, making the effect of temperature on dispersal difficult to predict. Using a high-resolution (as high as 200m) empirically-calibrated biophysical model of coral larval dispersal for the southern Great Barrier Reef, we show that a 2°C warming will increase local retention, decrease the distance larvae disperse, and reduce number of connections between reefs, whereas projected changes in large-scale currents have limited effects. Collectively, these shifts imply that 2°C of warming will reduce inter-reef connectivity, hampering recovery after disturbances and reducing the spread of warm-adapted genes. Such changes make protections more effective locally, but may require reducing spacing of protected areas.

 

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