Effects of Exotic Eradication on Ecosystem Structure and Function

在内华达山脉的高山湖泊中，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外来鳟鱼灭绝后这些物种的自然恢复率以及引入鳟鱼对湖泊生态系统功能的影响。将通过进行全湖实验来研究鳟鱼移除后青蛙和无脊椎动物的恢复情况。在全湖实验中，将移除鳟鱼的湖泊与有鳟鱼的湖泊进行比较。调查人员还将对塞拉利昂的湖泊进行大规模调查，这些湖泊在时间长短上有所不同，因为鳟鱼种群已经自然灭绝。生态系统功能的变化将通过测量水柱中发现的藻类与基质上的藻类对整体湖泊生产力的相对贡献来估计。外来物种的引入导致了本地物种的灭绝和生态系统功能的巨大变化。虽然外来物种引入对生态系统的影响已被广泛研究，但对外来物种灭绝后生态系统恢复的定量研究却极为罕见。这些研究对于确定生态系统在物种消失后是否会恢复到自然状态，以及这种恢复需要多长时间是至关重要的。此外，从外来物种根除的实验研究中可以了解到许多关于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.