Hefley Trevor J, Hooten Mevin B, Drake John M, Russell Robin E, Walsh Daniel P
Department of Statistics and Department of Fish, Wildlife, and Conservation Biology, Colorado State University, Fort Collins, CO, 80523, USA.
U.S. Geological Survey, Colorado Cooperative Fish and Wildlife Unit, Fort Collins, CO, 80523, USA.
Ecol Lett. 2016 Nov;19(11):1353-1362. doi: 10.1111/ele.12671. Epub 2016 Sep 28.
Inferring the factors responsible for declines in abundance is a prerequisite to preventing the extinction of wild populations. Many of the policies and programmes intended to prevent extinctions operate on the assumption that the factors driving the decline of a population can be determined. Exogenous factors that cause declines in abundance can be statistically confounded with endogenous factors such as density dependence. To demonstrate the potential for confounding, we used an experiment where replicated populations were driven to extinction by gradually manipulating habitat quality. In many of the replicated populations, habitat quality and density dependence were confounded, which obscured causal inference. Our results show that confounding is likely to occur when the exogenous factors that are driving the decline change gradually over time. Our study has direct implications for wild populations, because many factors that could drive a population to extinction change gradually through time.
推断导致种群数量下降的因素是防止野生种群灭绝的前提条件。许多旨在防止物种灭绝的政策和计划都是基于这样一种假设，即可以确定导致种群数量下降的因素。导致种群数量下降的外源性因素可能会与诸如密度依赖性等内源性因素在统计上相互混淆。为了证明这种混淆的可能性，我们进行了一项实验，通过逐步改变栖息地质量，使多个重复种群走向灭绝。在许多重复种群中，栖息地质量和密度依赖性相互混淆，这模糊了因果推断。我们的结果表明，当导致种群数量下降的外源性因素随时间逐渐变化时，混淆很可能会发生。我们的研究对野生种群有直接影响，因为许多可能导致种群灭绝的因素会随着时间逐渐变化。
