Phase shifts, herbivory, and the resilience of coral reefs to climate change
Phase shifts, herbivory, and the resilience of coral reefs to climate change
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DOI：
10.1016/j.cub.2006.12.049
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发表时间：
2007-02-20
期刊：
影响因子：
9.2
通讯作者：
Willis, Bette
中科院分区：
文献类型：
--
作者：
Hughes, Terence P.;Rodrigues, Maria J.;Willis, Bette
由于过度捕捞、水质下降以及气候变化的直接和间接影响的综合影响，世界范围内的许多珊瑚礁经历了相移到交替的退化组合[1-9]。在这里，我们通过实验控制了大型食草鱼类的密度，以测试它们在1998年区域性白化（迄今为止有记录的最大珊瑚死亡事件）之后对珊瑚组合恢复力的影响。这项实验是在大堡礁进行的，在一个禁止捕鱼的保护区内，珊瑚的丰度和多样性因白化而急剧减少。在鱼类丰富的控制区，藻类的丰度仍然很低，而珊瑚的覆盖率在3年期间几乎翻了一番（达到20%），这主要是由于在当地因白化而灭绝的物种被重新吸收。相反，大型草食性鱼类的消失导致了大型藻类的急剧爆发，这抑制了珊瑚的繁殖力、繁殖和生存。因此，鱼类资源管理是防止相移和管理珊瑚礁恢复力的关键组成部分。重要的是，当地对捕鱼工作的管理是保护珊瑚礁的一个容易实现的目标，这种地方行动也可以提供一些保险，以防止大规模的干扰，如大规模的白化，这是不切实际的直接管理。
Many coral reefs worldwide have undergone phase shifts to alternate, degraded assemblages because of the combined effects of overfishing, declining water quality, and the direct and indirect impacts of climate change [1-9]. Here, we experimentally manipulated the density of large herbivorous fishes to test their influence on the resilience of coral assemblages in the aftermath of regional-scale bleaching in 1998, the largest coral mortality event recorded to date. The experiment was undertaken on the Great Barrier Reef, within a no-fishing reserve where coral abundances and diversity had been sharply reduced by bleaching [10]. In control areas, where fishes were abundant, algal abundance remained low, whereas coral cover almost doubled (to 20%) over a 3 year period, primarily because of recruitment of species that had been locally extirpated by bleaching. In contrast, exclusion of large herbivorous fishes caused a dramatic explosion of macroalgae, which suppressed the fecundity, recruitment, and survival of corals. Consequently, management of fish stocks is a key component in preventing phase shifts and managing reef resilience. Importantly, local stewardship of fishing effort is a tractable goal for conservation of reefs, and this local action can also provide some insurance against larger-scale disturbances such as mass bleaching, which are impractical to manage directly.