Operation of a Trophic Cascade in Predator-free Forest Fragments

捕食在调节陆地生态系统中的作用，以及陆地生态系统是否受到强烈的营养级联（从捕食者到食草动物再到植物的影响）的相关问题是当前生态学中争论的话题。这项拟议中的研究利用了一项耗资数十亿美元的“实验”，该实验在委内瑞拉一个水电设施相关的4300平方公里的蓄水区创造了大量没有捕食者的岛屿。提出的研究大体上验证了这样一个假设，即岛屿上无捕食者的状态最初会导致草食动物（以种子和树叶为食的物种）的极度丰富，然后由于营养级联而对植被产生巨大影响。主要活动包括在实验岛屿上继续进行啮齿动物和蚂蚁清除计划，并重新调查植物地块，以记录未处理和处理岛屿上植被变化的动态。这项研究可能为大型食肉动物在热带森林中扮演的重要功能角色提供最直接的联系。这对保护具有巨大的影响，因为人类造成的热带森林捕食者的减少可能会大大改变热带森林的植物物种组成，导致多样性显著下降。

The role of predation in regulating terrestrial ecosystems, and the related question of whether terrestrial ecosystems are subject to strong trophic cascades (effects which flow from predators through herbivores to plants) are topics of current debate in ecology. The proposed research takes advantage of a multi-billion dollar "experiment" that has created a large number of predator-free islands in a 4,300 square-kilometer impoundment associated with a hydroelectric installation in Venezuela. The proposed research generally tests the hypothesis that the predator-free status of islands should lead initially to a hyper-abundance of herbivores (seed and leaf eating species), and then to massive impacts on the vegetation as a consequence of trophic cascades. Primary activities include continuing rodent and ant removal programs on experimental islands and re-censusing plant plots to record the dynamics of vegetation change on both untreated and treated islands. This research may provide the most direct link yet to the important functional role played by large predators in tropical forests. This has enormous implications for conservation because human-induced loss of predators from tropical forests may drastically alter plant species composition of tropical forests resulting in significant declines in diversity.