Evolution and Ecology Research Centre, School of Biological, Earth and Environmental Science, University of New South Wales, Sydney, 2052 New South Wales, Australia.
Ecology. 2013 Jan;94(1):25-31. doi: 10.1890/12-0592.1.
Contrasting patterns in the diversity-invasibility relationship have intrigued ecologists for many years, and are now known as the "invasion paradox." Experiments usually detect negative relationships, while field surveys find them to be positive. It is widely believed that the paradox is driven by differences in spatial scale, but this is challenged by field surveys that find positive relationships at all spatial scales. If factors that determine invasion dynamics change during the invasion process, the paradox may be partially driven by differences in temporal scale. Here we used simulation (cellular automata) models to explore the generality of temporal change in the diversity-invasibility relationship. The probability of invaders colonizing an area was inversely related to the density of natives, creating a negative native-exotic correlation when invaders first arrived. Over time, native and exotic populations were both shaped by the same post-introduction processes (disturbance, dispersal, and recolonization), shifting their correlation to positive. The rate of temporal change in the diversity-invasibility relationship was mainly dependent upon the fecundity of invaders. Greater fecundity meant that invaders spread through the landscape faster and were subject to post-introduction processes sooner. We propose a unified conceptual model where the diversity-invasiblity relationship is a function of both spatial and temporal scales.
多年来，生物多样性与入侵性之间的关系一直令生态学家感到好奇，现在被称为“入侵悖论”。实验通常检测到负相关关系，而实地调查则发现它们是正相关的。人们普遍认为，这种悖论是由空间尺度的差异驱动的，但实地调查却发现，在所有空间尺度上都存在正相关关系，这对这种观点提出了挑战。如果决定入侵动态的因素在入侵过程中发生变化，那么这种悖论可能部分是由时间尺度的差异驱动的。在这里，我们使用模拟（元胞自动机）模型来探索多样性-入侵性关系随时间变化的普遍性。入侵者在一个地区定居的概率与本地居民的密度成反比，当入侵者最初到达时，会产生负的本地-外来相关关系。随着时间的推移，本地和外来种群都受到相同的引入后过程（干扰、扩散和再定居）的影响，它们的相关性转变为正相关。多样性-入侵性关系随时间变化的速度主要取决于入侵者的繁殖力。更高的繁殖力意味着入侵者更快地在景观中传播，并更早地受到引入后过程的影响。我们提出了一个统一的概念模型，其中多样性-入侵性关系是空间和时间尺度的函数。
