Caldow Richard W G, Stillman Richard A, dit Durell Sarah E A le V, West Andy D, McGrorty Selwyn, Goss-Custard John D, Wood Philippa J, Humphreys John
Centre for Ecology and Hydrology, CEH Dorset, Winfrith Technology Centre, Dorchester, Dorset DT2 8ZD, UK.
Proc Biol Sci. 2007 Jun 7;274(1616):1449-55. doi: 10.1098/rspb.2007.0072.
Introductions of non-native species are seen as major threats to ecosystem function and biodiversity. However, invasions of aquatic habitats by non-native species are known to benefit generalist consumers that exhibit dietary switches and prey upon the exotic species in addition to or in preference to native ones. There is, however, little knowledge concerning the population-level implications of such dietary changes. Here, we show that the introduction of the Manila clam Tapes philippinarum into European coastal waters has presented the Eurasian oystercatcher Haematopus ostralegus ostralegus with a new food resource and resulted in a previously unknown predator-prey interaction between these species. We demonstrate, with an individuals-based simulation model, that the presence of this non-native shellfish, even at the current low density, has reduced the predicted over-winter mortality of oystercatchers at one recently invaded site. Further increases in clam population density are predicted to have even more pronounced effects on the density dependence of oystercatcher over-winter mortality. These results suggest that if the Manila clam were to spread around European coastal waters, a process which is likely to be facilitated by global warming, this could have considerable benefits for many shellfish-eating shorebird populations.
外来物种的引入被视为对生态系统功能和生物多样性的主要威胁。然而，已知外来物种对水生生境的入侵会使那些具有食性转换能力、除本地物种外还捕食或优先捕食外来物种的泛化消费者受益。然而，对于这种食性变化在种群水平上的影响却知之甚少。在此，我们表明，菲律宾蛤仔引入欧洲沿海水域为欧亚蛎鹬提供了一种新的食物资源，并导致了这些物种之间此前未知的捕食者 - 猎物相互作用。我们通过基于个体的模拟模型证明，即使在当前低密度情况下，这种外来贝类的存在也降低了一个最近被入侵地点蛎鹬预测的越冬死亡率。预计蛤仔种群密度的进一步增加将对蛎鹬越冬死亡率的密度依赖性产生更显著的影响。这些结果表明，如果菲律宾蛤仔在欧洲沿海水域扩散，这一过程可能会因全球变暖而加速，那么这可能会给许多以贝类为食的滨鸟种群带来相当大的益处。
