Dissertation Research: Habitat Fragmentation Effects on the Stopover Biology of Migratory Landbirds along the Northern Coast of the Gulf of Mexico

栖息地破碎化及其对繁殖地和越冬地的相关影响已被认为是导致许多近北极-新热带候鸟种群数量下降的主要因素。然而，我们对破碎化如何影响候鸟迁徙中途栖息地的可及性、利用和质量知之甚少。我们提出了一个假设，即中途停留栖息地的碎片化限制了移民在迁徙中生存和在良好的营养条件下到达目的地的能力。我们将研究栖息地破碎化对候鸟迁徙的影响程度、可选择的中途栖息地选择以及候鸟在墨西哥湾北部海岸春季过境时中途栖息地的内在适宜性。利用遥感数据对栖息地的可用性进行表征，同时通过在不同组成、大小和隔离的生境斑块内释放放射性标记的画眉鸟（Hylocichla mustelina），研究候鸟在中途停留期间的栖息地使用情况。研究结果将提高我们对陆鸟候鸟经停生态的认识，以及确定合适的经停生境的决定因素。它们还将增强我们确定迁徙期对人口限制的相对重要性的能力。除非在迁徙过程中对栖息地的需求被考虑到保护方程中，否则洲际迁徙者的数量将继续下降。

PROJECT SUMMARYHabitat fragmentation and its associated effects on the breeding and wintering grounds have beenimplicated as major factors contributing to the declines of many Nearctic-Neotropical migratory landbird populations. However, we know little about how fragmentation may affect the accessibility, use and quality of stopover habitats for birds during migration. We advance the hypothesis that fragmentation of stopover habitats imposes constraints on the ability of migrants to survive migration and to arrive at their destination in good nutritional condition. We will investigate the degree to which habitat fragmentation influences bird movement, choice of available stopover habitats, and the intrinsic suitability of stopover habitats when migrants stopover along the northern coast of the Gulf of Mexico during spring passage. Habitat availability will be characterized using remotely-sensed data, while habitat use by migrants during stopover will be studied by releasing radio-tagged Wood Thrushes (Hylocichla mustelina ) within habitat patches of different composition, size, and isolation. The results will improve our understanding of the stopover ecology of landbird migrants and the determinants of suitable stopover habitat. They will also further our ability to determine the relative importance of the migratory period for population limitation.Populations of intercontinental migrants will continue to decline unless habitat requirements duringmigration are factored into the conservation equation.