Landcare Research, PO Box 40, Lincoln 7640, New Zealand.
Ecol Lett. 2011 Oct;14(10):1035-42. doi: 10.1111/j.1461-0248.2011.01673.x. Epub 2011 Aug 2.
Invasive species are frequently the target of eradication or control programmes to mitigate their impacts. However, manipulating single species in isolation can lead to unexpected consequences for other species, with outcomes such as mesopredator release demonstrated both theoretically and empirically in vertebrate assemblages with at least two trophic levels. Less is known about the consequences of species removal in more complex assemblages where a greater number of interacting invaders increases the potential for selective species removal to result in unexpected changes in community structure. Using a replicated Before-After Control-Impact field experiment with a four-species assemblage of invasive mammals we show that species interactions in the community are dominated by competition rather than predation. There was no measurable response of two mesopredators (rats and mice) following control of the top predator (stoats), but there was competitive release of rats following removal of a herbivore (possums), and competitive release of mice following removal of rats.
入侵物种通常是根除或控制计划的目标，以减轻其影响。然而，单独操纵单一物种可能会对其他物种产生意想不到的后果，例如在至少有两个营养级的脊椎动物组合中，从理论和实证上都证明了中捕食者释放。在更复杂的组合中，由于更多相互作用的入侵者增加了选择性物种去除导致社区结构意外变化的可能性，因此对物种去除的后果知之甚少。我们使用具有四种入侵哺乳动物的群落的重复前后对照实验表明，群落中的物种相互作用主要是竞争而不是捕食。在顶级捕食者（白鼬）得到控制后，没有观察到两种中捕食者（老鼠和老鼠）的可测量反应，但在食草动物（负鼠）被移除后，老鼠有竞争释放，而在老鼠被移除后，老鼠有竞争释放。
