Effects of Exotic Eradication on Ecosystem Structure and Function

在内华达州的高山湖泊中，非本地鳟鱼的广泛放养与两栖动物和无脊椎动物的减少有关。 该项目的目标是确定这些物种的自然恢复率后，消除外来鳟鱼和鳟鱼引进湖泊生态系统的功能的影响。 青蛙和无脊椎动物的恢复后，鳟鱼删除将进行研究，其中湖泊鳟鱼被删除相比，湖泊与鳟鱼进行全湖实验。 调查人员还将对塞拉湖进行大规模的调查，这些湖泊自鳟鱼种群自然灭绝以来的时间长短各不相同。 生态系统功能的变化将通过测量水柱中藻类与基质上藻类对湖泊总体生产力的相对贡献来估计。 外来物种的引进造成了本地物种的灭绝和生态系统功能的巨大变化。虽然外来物种的引入对生态系统的影响已经得到了广泛的研究，但对外来物种灭绝后生态系统恢复的定量研究却极为少见。 这些研究对于确定物种被移走后生态系统是否通常恢复到自然状态以及恢复需要多长时间至关重要。 此外，通过对外来物种灭绝的实验研究，我们可以了解群落聚集的自然过程。

In alpine lakes of the Sierra Nevada, the widespread stocking of non-native trout has been implicated in the decline of amphibians and invertebrates. The objectives of this project are to determine natural rates of recovery of these species after the eradication of exotic trout and the effect of trout introduction on the functioning of the lake ecosystem. Recovery of frogs and invertebrates after trout removal will be studied by performing whole-lake experiments in which lakes from which trout are removed are compared to lakes with trout. The investigators will also perform a broad-scale survey of Sierra lakes that vary in the length of time since trout populations have died out naturally. Changes in ecosystem function will be estimated by measuring the relative contributions to overall lake productivity of algae found in the water column versus algae on substrate. The introduction of exotic species has caused extinctions of native species and large changes in the functioning of ecosystems. Although the effects of exotic species introduction have been studied widely, quantitative studies of ecosystem recovery after exotic species eradication are exceedingly rare. Such studies are essential to determine whether ecosystems typically return to their natural condition after the species are removed, and how long such recovery takes. In addition, much can be learned about the natural process of community assembly from experimental study of exotic eradication.