Overfishing reduces resilience of kelp beds to climate-driven catastrophic phase shift
Overfishing reduces resilience of kelp beds to climate-driven catastrophic phase shift
复制标题
DOI：
10.1073/pnas.0907529106
复制
发表时间：
2009-12-29
影响因子：
11.1
通讯作者：
Ridgway, K. R.
中科院分区：
文献类型：
--
作者：
Ling, S. D.;Johnson, C. R.;Ridgway, K. R.
在评估气候变化的影响时，一个关键的考虑因素是与其他人为应激源产生协同效应的可能性。在海洋领域，气候变化和过度捕捞对海洋生态系统的结构和功能构成两大挑战。在塔斯马尼亚东部，温带沿海水域变暖的速度大约是全球海洋变暖平均值的四倍，是南半球变暖速度最快的地区。这推动了具有重要生态意义的长刺海胆(Centrostephanus Rodgersii)的活动范围扩大，现在已经开始对生产性塔斯马尼亚海带进行灾难性的过度放牧，导致生物多样性和重要的岩礁生态系统服务的丧失。在过度放牧的同时，大量捕捞以珊瑚礁为基础的捕食者，包括带刺的龙虾Jasus edwardsii。通过在海洋保护区内外进行实验，我们表明，捕捞大型捕食性龙虾降低了海藻对气候驱动的海胆威胁的抵抗力，从而增加了向广泛的海胆荒地转移的灾难性风险。这表明，多种人为应激源之间的相互作用会加剧生态系统对气候变化的非线性反应，并限制这些系统的适应能力。面对持续变暖和捕食者从世界海洋中消失的空前程度，以减少生态系统灾难性相变风险为重点的管理行动尤为紧迫。
A key consideration in assessing impacts of climate change is the possibility of synergistic effects with other human-induced stressors. In the ocean realm, climate change and overfishing pose two of the greatest challenges to the structure and functioning of marine ecosystems. In eastern Tasmania, temperate coastal waters are warming at approximately four times the global ocean warming average, representing the fastest rate of warming in the Southern Hemisphere. This has driven range extension of the ecologically important long-spined sea urchin (Centrostephanus rodgersii), which has now commenced catastrophic overgrazing of productive Tasmanian kelp beds leading to loss of biodiversity and important rocky reef ecosystem services. Coincident with the overgrazing is heavy fishing of reef-based predators including the spiny lobster Jasus edwardsii. By conducting experiments inside and outside Marine Protected Areas we show that fishing, by removing large predatory lobsters, has reduced the resilience of kelp beds against the climate-driven threat of the sea urchin and thus increased risk of catastrophic shift to widespread sea urchin barrens. This shows that interactions between multiple human-induced stressors can exacerbate nonlinear responses of ecosystems to climate change and limit the adaptive capacity of these systems. Management actions focused on reducing the risk of catastrophic phase shift in ecosystems are particularly urgent in the face of ongoing warming and unprecedented levels of predator removal from the world's oceans.