Linking movement of individuals with population-level responses to habitat loss and fragmentation

栖息地的迁移把大型的、连续的栖息地变成了更小的、破碎的栖息地。对于许多物种来说，小生境比大生境更不适合，而且随着生境的消失，局部灭绝的风险也会增加。一些物种表现出种群规模较小的适应度降低的现象（也称为Allee效应），并且由于栖息地减少导致种群数量减少，适应度降低，因此尤其面临栖息地迁移的风险。例如，南方鼯鼠（Glaucomys volans）在冬季作为一个群体筑巢，以减少每只松鼠暴露在环境温度下的表面积。如果松鼠的冬季存活率与巢群大小正相关，那么这些松鼠在较小的群体中冬季死亡率更高，并且在较小的栖息地中面临局部灭绝的风险。这个研究项目包括测试动物行为、栖息地迁移和灭绝风险之间的关系。我们将使用巢箱实验来控制冬季飞鼠巢群的大小，以测试群体大小是否与生存有关。我们还将在不同大小的栖息地对鼯鼠进行实地调查，以验证以下预测：存在一个最小栖息地面积的阈值，使鼯鼠不能因Allee效应而占用较小的栖息地；最小栖息地面积阈值随冬季气温的严重程度（例如，随纬度）而变化。

Habitat removal turns large, contiguous habitats into smaller, fragmented ones. For many species small habitats are less suitable than large ones, and the risk of local extinction is increased as habitat is removed. Some species exhibit a phenomenon of lowered fitness with smaller population size (also called an Allee effect), and are especially at risk from habitat removal since less habitat will result in smaller populations with lower fitness. For example, southern flying squirrels (Glaucomys volans) nest as a group during winter in order to reduce the amount of surface area that each squirrel exposes to ambient temperatures. If winter survival of squirrels is positively related to nest group size, then these squirrels will have higher winter mortality in smaller groups, and be at risk of local extinctions in small habitats. This research program involves testing for the relationships between animal behaviour, habitat removal, and extinction risk. We will be using a nest box experiment to manipulate the size of flying squirrel nest groups during winter, to test whether group size is related to survival. We will also undertake field surveys of flying squirrels in habitats of different sizes to test the predictions that: there is a threshold minimum habitat area, such that flying squirrels can not occupy smaller habitats because of an Allee effect; and the minimum habitat area threshold varies with the severity of winter temperatures (for example, with latitude).