Centre for Environment, Fisheries & Aquaculture Science (Cefas), Pakefield Road, Lowestoft, NR33 0HT, UK.
School of Earth Sciences, University of Bristol, Bristol, BS8 1RJ, UK.
Glob Chang Biol. 2023 Jul;29(13):3794-3805. doi: 10.1111/gcb.16690. Epub 2023 Apr 19.
Coral reef ecosystems are expected to undergo significant declines over the coming decades as oceans become warmer and more acidic. We investigate the environmental tolerances of over 650 Scleractinian coral species based on the conditions found within their present-day ranges and in areas where they are currently absent but could potentially reach via larval dispersal. These "environmental envelopes" and connectivity constraints are then used to develop global forecasts for potential coral species richness under two emission scenarios, representing the Paris Agreement target ("SSP1-2.6") and high levels of emissions ("SSP5-8.5"). Although we do not directly predict coral mortality or adaptation, the projected changes to environmental suitability suggest considerable declines in coral species richness for the majority of the world's tropical coral reefs, with a net loss in average local richness of 73% (Paris Agreement) to 91% (High Emissions) by 2080-2090 and particularly large declines across sites in the Great Barrier Reef, Coral Sea, Western Indian Ocean, and Caribbean. However, at the regional scale, we find that environmental suitability for the majority of coral species can be largely maintained under the Paris Agreement target, with 0%-30% potential net species lost in most regions (increasing to 50% for the Great Barrier Reef) as opposed to 80%-90% losses under High Emissions. Projections for subtropical areas suggest that range expansion will give rise to coral reefs with low species richness (typically 10-20 coral species per region) and will not meaningfully offset declines in the tropics. This work represents the first global projection of coral species richness under oceanic warming and acidification. Our results highlight the critical importance of mitigating climate change to avoid potentially massive extinctions of coral species.
在未来几十年内，随着海洋变暖变酸，珊瑚礁生态系统预计将经历重大衰退。我们根据当前范围内的条件以及目前不存在但可能通过幼虫扩散到达的区域，研究了超过 650 种石珊瑚物种的环境耐受性。然后，这些“环境范围”和连通性限制用于根据两个排放情景（代表《巴黎协定》目标“SSP1-2.6”和高排放水平“SSP5-8.5”），对潜在珊瑚物种丰富度进行全球预测。虽然我们没有直接预测珊瑚死亡率或适应性，但环境适宜性的预计变化表明，世界上大多数热带珊瑚礁的珊瑚物种丰富度将大幅下降，到 2080-2090 年，平均本地丰富度将净减少 73%（《巴黎协定》）至 91%（高排放），尤其是大堡礁、珊瑚海、西印度洋和加勒比地区的珊瑚礁站点的下降幅度特别大。然而，在区域尺度上，我们发现，在《巴黎协定》目标下，大多数珊瑚物种的环境适宜性可以基本保持，大多数地区的潜在净物种损失为 0%-30%（大堡礁地区增加到 50%），而在高排放情况下，损失为 80%-90%。对亚热带地区的预测表明，范围扩大将导致珊瑚礁物种丰富度较低（每个地区通常有 10-20 种珊瑚），并且不会对热带地区的下降产生有意义的补偿。这项工作代表了在海洋变暖酸化下珊瑚物种丰富度的首次全球预测。我们的结果强调了缓解气候变化以避免珊瑚物种大规模灭绝的至关重要性。
