Trophic cascades promote threshold-like shifts in pelagic marine ecosystems
Trophic cascades promote threshold-like shifts in pelagic marine ecosystems
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DOI：
10.1073/pnas.0806649105
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发表时间：
2009-01-06
影响因子：
11.1
通讯作者：
Kornilovs, Georgs
中科院分区：
文献类型：
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作者：
Casini, Michele;Hjelm, Joakim;Kornilovs, Georgs
渔业可以对海洋生态系统产生巨大影响，因为消除大型掠食性鱼类的影响可能会沿着食物链向下传递。这些级联过程对系统功能和弹性的影响仍然是激烈的科学争论的根源。通过使用覆盖 30 年的实地数据，我们表明波罗的海在顶级捕食者鳕鱼崩溃后，营养级联的潜在机制导致了生态系统功能的转变。我们确定了一个生态阈值，对应于大约 17 x 10(10) 个个体的浮游动物丰度，该阈值区分了两种生态系统配置，其中浮游动物动态由水文气候力或捕食压力驱动。浮游动物西鲱的丰度高于阈值，使浮游动物动态与水文环境脱钩。目前西鲱对幼鳕捕食资源的强烈监管可能会阻碍鳕鱼的恢复和生态系统恢复到之前的状态。这就要求在管理决策中纳入食物网视角。
Fisheries can have a large impact on marine ecosystems, because the effects of removing large predatory fish may cascade down the food web. The implications of these cascading processes on system functioning and resilience remain a source of intense scientific debate. By using field data covering a 30-year period, we show for the Baltic Sea that the underlying mechanisms of trophic cascades produced a shift in ecosystem functioning after the collapse of the top predator cod. We identified an ecological threshold, corresponding to a planktivore abundance of approximate to 17 x 10(10) individuals, that separates 2 ecosystem configurations in which zooplankton dynamics are driven by either hydroclimatic forces or predation pressure. Abundances of the planktivore sprat above the threshold decouple zooplankton dynamics from hydrological circumstances. The current strong regulation by sprat of the feeding resources for larval cod may hinder cod recovery and the return of the ecosystem to a prior state. This calls for the inclusion of a food web perspective in management decisions.