Correlated extinctions, colonizations and population fluctuations in a highly connected ringlet butterfly metapopulation
Correlated extinctions, colonizations and population fluctuations in a highly connected ringlet butterfly metapopulation
复制标题
高度关联的小环蝴蝶种群中相关的灭绝、殖民化和种群波动
作者：
Odette L. Sutcliffe;C. Thomas;T. Yates;J. Greatorex
摘要：集合种群的持久性可能高度依赖于栖息地斑块之间的种群动态是否因斑块之间的迁移和空间相关的环境随机性（天气影响）而相关。我们研究了小环蝴蝶 (Aphantopus hyperantus) 在大约 0.5 平方公里的区域内的种群动态在灭绝、定植和种群波动方面是否同步。僧侣木蝴蝶监测计划 1973 年至 1995 年横断面计数数据揭示了 (A) 一个主要的环境扰动，即 1976 年的干旱，导致了 A. hyperantus 在随后的几年中同步灭绝，(B) 在大量明显灭绝之后的几年中同步重新定殖，以及 (C) A. hyperantus 的种群变化在横断面的 14 个断面中高度相关，可能反映了对环境随机性的类似反应，以及部门之间的个人交换。然而，灭绝和种群同步取决于栖息地类型。 1976年干旱之后，A. hyperantus显然从它所占据的最开放和最阴凉的栖息地灭绝了，中间阴影的栖息地仍然存在一些，因此显示出收缩到环境梯度中心部分的核心种群，尽管平均转移到相对开放的栖息地。位于环境梯度极端的 A. hyperantus 种群波动最不同步，表明生境异质性具有潜在的缓冲作用，但这对于 1976 年干旱后的生存并不重要。因此，并非所有栖息地对于持久性都同样重要。相关的时间动态、栖息地质量的变化以及栖息地质量和时间环境随机性之间的相互作用是集合种群持久性的重要决定因素，应纳入集合种群模型中。
Abstract The persistence of metapopulations is likely to be highly dependent on whether population dynamics are correlated among habitat patches as a result of migration between patches and spatially-correlated environmental stochasticity (weather effects). We examined whether population dynamics of the ringlet butterfly, Aphantopus hyperantus, were synchronous in an area of approximately 0.5 km2, with respect to extinction, colonization and population fluctuations. Monks Wood Butterfly Monitoring Scheme transect count data from 1973 to 1995, revealed (A) a major environmental perturbation, the drought of 1976, which caused synchronized extinctions of A. hyperantus in subsequent years, (B) synchronized recolonization in years following the large number of apparent extinctions, and (C) population changes by A. hyperantus were highly correlated in many of the 14 sections of the transect, presumably reflecting similar responses to environmental stochasticity, and the exchange of individuals among sections. However, extinction and population synchrony depended on habitat type. Following the 1976 drought, A. hyperantus apparently became extinct from the most open and most shady habitats it occupied, with some persistence in habitats of intermediate shading, thus showing retraction to core populations in central parts of an environmental gradient, albeit with an average shift to relatively open habitat. Populations at extreme ends of the environmental gradient occupied by A. hyperantus fluctuated least synchronously, suggesting a potential buffering effect of habitat heterogeneity, but this was not crucial to survival after the 1976 drought. Thus, not all habitats are equally important to persistence. Correlated temporal dynamics, variation in habitat quality and the interaction between habitat quality and temporal environmental stochasticity are important determinants of metapopulation persistence and should be incorporated in metapopulation models.