Habitat Patchiness, Dispersal and Population Structure: Tests of Patch Dynamic and Demographic Models Using Small Mammals

最近开发的一类模型表明，在空间分离的亚种群之间运行的过程可能会影响当地种群的动态。从理论上讲，这些模型不仅直接适用于理解大尺度的物种丰度格局，而且还可用于评估生境破碎化/斑块化对相关物种的影响程度。衡量物种对生境斑块性反应的关键因素是：i)相对于斑块隔离和分散的扩散能力；社会结构的斑块差异决定了个体斑块是移民的净生产者还是净消费者。然而，很少有研究审查这些因素对野外种群的重要性。本文研究了两种小型哺乳动物对36 ha生境斑块景观的响应。将破碎系统中的亚种群与连续（非破碎）生境控制中的亚种群进行比较。目的包括检查斑块大小、动物扩散能力之间的相互作用，以及它们如何影响和受斑块间种群结构变化的影响。该系统将作为一个经验模型，用于研究种群分散对居住在异质生境、斑块和/或受到破碎化威胁的生境的重要性。

A recently developed class of models demonstrate that local population dynamics can be influenced by processes that operate between spatially separated sub-populations. In theory these models are directly applicable not only to understanding large- scale patterns of abundance but in evaluating the degree to which habitat fragmentation/patchiness affects species of concern. Critical factors in gauging species responses to habitat patchiness are: i) dispersal ability relative to patch isolation and dispersion; and ii) patch differences in social structure that determine whether individual patches are net producers or consumers of immigrants. Few studies, however, have examined the importance of these factors to field populations. Here we propose to study the responses of two small mammal species to an experimentally created landscape of habitat patches distributed over a 36 ha area. Sub-populations within the fragmented system would be compared to that in a continuous (unfragmented) habitat control. Objectives include examination of the interplay between patch size, animal dispersal ability, and how these affect--and are affected by--patch to patch variation in population structure. This system will serve as an empirical model for studying the importance of dispersal to populations inhabiting heterogeneous habitats, patches, and /or habitats that are threatened with fragmentation.