Are corals coming to a reef near you? Projected extension of suitable thermal conditions for hard coral communities along the east Australian coast

Climate change is driving the poleward redistribution of coral species, but the rate and magnitude of future range extensions within temperate regions are rarely quantified. A better understanding of the likely future distribution of corals is needed to anticipate the resulting social, economic and environmental implications. Here, we project the rate and magnitude of extensions of suitable thermal conditions for hard coral communities along the east Australian coastline, using data on coral community presence, in conjunction with historical and projected ocean temperatures. Our projections indicate that temperatures will be suitable for coral communities dominated by the subtropical coral Pocillopora aliciae, currently found off Sydney, to extend their range poleward by 80 (RCP 2.6) to 450 km (RCP 8.5) by 2100, corresponding to a rate of 0.9-5.0 km year(-1). Similarly, thermal conditions will be such that diverse coral communities, such as those currently occurring in the Solitary Islands, may extend their range by 130 (RCP 2.6) to 580 km (RCP 8.5) by 2100, at a rate of 1.4-6.4 km year(-1). These projections are similar to those forecast for coral species in other parts of the world. Newly establishing coral communities in temperate regions may provide a range of novel local economic opportunities, particularly for marine tourism.

Automated summary

Climate change is causing coral species to move towards the poles, but the rate and extent of such movements in temperate regions are rarely studied. It is important to understand the future distribution of corals to anticipate the social, economic, and environmental consequences. This study projects the expansion of suitable thermal conditions for coral communities along the east Australian coast using data on coral presence and ocean temperatures. The findings show that coral communities dominated by subtropical coral species could extend their range by 80 to 450 km by the year 2100, and diverse coral communities may expand by 130 to 580 km. These projections are similar to those in other parts of the world, and the establishment of coral communities in temperate regions could create new economic opportunities, particularly in marine tourism.