Research press release




今回、Rick Stuart-Smithたちの研究グループは、2016年の大量白化事象以後のサンゴ、藻類、魚類、および移動性無脊椎動物(ウニなど)の生態系の変化を調査した。大量白化事象の前(2010~2015年)と後(白化事象の8~12カ月後)のデータを使って、グレートバリアリーフ沿いとサンゴ海のサンゴ礁地帯の計186カ所を調査した結果、このうち44カ所で、生きているサンゴの被度が10%以上減少し、北側のサンゴ海ではサンゴ礁が最も一貫して失われていたことが分かった。そして、最も被害の大きかったサンゴ礁では、サンゴを餌とする魚類が明白に減少していた。



The 2016 mass bleaching event across the Great Barrier Reef and Coral Sea resulted in rapid, regional scale changes in marine communities that are dependent on reefs, according to a study published online in Nature this week. The study shows that fish community structures on southern reefs have become more similar to those in the north and invertebrate communities have also changed considerably.

Rick Stuart-Smith and colleagues investigated the ecological changes in corals, algae, fish and mobile invertebrates (such as sea urchins) following the 2016 mass bleaching event. The authors surveyed 186 reef sites along the Great Barrier Reef and in the Coral Sea before the bleaching event (data from 2010 to 2015) and afterwards (data from 8 to 12 months after the event). They found that 44 of the surveyed sites experienced declines in live coral cover of more than 10%, with the northern Coral Sea reefs suffering the most consistent losses. In addition, declines in coral-eating fish were evident at the most heavily affected reefs.

However, the authors suggest that region-wide ecological changes occurred largely independent of coral loss and seemed to be directly linked to sea temperature. They found evidence of community-wide trophic restructuring, with weakening of pre-existing latitudinal gradients in the diversity of fish, invertebrates and their functional groups. For example, northern reefs saw a decrease in the number of local species of fish whereas there was an increase in the number of small cryptic fish species on southern reefs.

On the basis of their observations, the authors conclude that the recovery process and the scale of the impact remain uncertain. The trajectories of bleached reefs will be greatly influenced by the new community structures that were observed, which are linked to warming-related reshuffling of reef communities.

doi: 10.1038/s41586-018-0359-9

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