Sudden collapse of a mesopredator reveals its complementary role in mediating rocky reef regime shifts
Sudden collapse of a mesopredator reveals its complementary role in mediating rocky reef regime shifts
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DOI：
10.1098/rspb.2018.0553
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发表时间：
2018-07-25
影响因子：
4.7
通讯作者：
Salomon, Anne K.
中科院分区：
文献类型：
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作者：
Burt, Jenn M.;Tinker, M. Tim;Salomon, Anne K.
虽然大量的基石捕食者的变化可能会产生级联效应，导致政权的转变，在这些过程中的作用mesopredators仍然未充分发掘。我们进行了年度调查的岩石礁社区，不同的恢复的基石捕食者（海獭，Enhydra lutris）和大规模死亡率的mesopredator（向日葵海星星，Pycnopodia helianthoides）由于传染性消耗性疾病。通过拟合人口模型的经验数据，我们表明，海獭的死亡率的大海胆的影响最大，但Pycnopodia下降对应的中型海胆增加311%，海带密度下降30%。我们的研究结果表明，捕食者在大小选择性猎物消费中的互补性加强了对海胆的自上而下的控制，通过增强海带森林的恢复力和侵蚀海胆贫瘠地的恢复力来影响替代珊瑚礁状态的恢复力。我们揭示了以前被低估的物种之间的相互作用，在一个“经典”的营养级联和政权转移，突出了中间层的捕食者在调解岩礁状态转换的关键作用。
While changes in the abundance of keystone predators can have cascading effects resulting in regime shifts, the role of mesopredators in these processes remains underexplored. We conducted annual surveys of rocky reef communities that varied in the recovery of a keystone predator (sea otter, Enhydra lutris) and the mass mortality of a mesopredator (sunflower sea star, Pycnopodia helianthoides) due to an infectious wasting disease. By fitting a population model to empirical data, we show that sea otters had the greatest impact on the mortality of large sea urchins, but that Pycnopodia decline corresponded to a 311% increase in medium urchins and a 30% decline in kelp densities. Our results reveal that predator complementarity in size-selective prey consumption strengthens top-down control on urchins, affecting the resilience of alternative reef states by reinforcing the resilience of kelp forests and eroding the resilience of urchin barrens. We reveal previously underappreciated species interactions within a 'classic' trophic cascade and regime shift, highlighting the critical role of middle-level predators in mediating rocky reef state transitions.