Turnover Dynamics in Two Patch-Tracking Sympatric Rail Metapopulations: Validating Inferences from Occupancy Data

本研究考察了居住在同一套湿地的受威胁的黑秧鸡和未受威胁的弗吉尼亚秧鸡所表现出的不同的种群殖民化和灭绝模式。这两种神秘的沼泽鸟类有着相似的自然历史，但根据存在-缺失调查得出的关系，它们飞往新地点的能力可能存在很大差异。这项研究将回答两个主要问题：从存在-缺失数据中暗示的殖民化模式是否与分散行为相对应？当占用的土地比例保持不变时，与占用率上升或下降时，人口流动的相关关系是否相同？通过对加利福尼亚州塞拉山麓众多小湿地的调查，本研究将：比较从周转量估计的扩散距离与从遥测和遗传结构直接测量的扩散距离；在最近由西尼罗病毒引起的灭绝事件后，追踪斑块的殖民化；利用遗传和同位素测量来确定殖民者的起源，以理清短距离和远距离分散的贡献；并通过检测所有捕获的铁轨的血液来监测西尼罗病毒的再次出现。这项研究产生的一个更广泛的影响将是发展与土地所有者合作的技术，以支持保护其土地上的稀有物种。私人土地支持着不成比例的濒危物种，关于根据《濒危物种法》保护物种的争议也时有发生。很少对私有财产进行实地研究。这项研究提供了一个独特的机会来探索与私人土地所有者合作的方式，并通过各种方法进行教育推广。该项目将通过培训研究生和本科生，并为当地土地所有者、奥杜邦志愿者、高中生和教师提供与研究人员一起体验该领域研究的机会，将研究和教育结合起来。这个项目的结果将通过产生关于区域种群之间的分散能力和连通性的重要数据来推进黑铁路的保护，并为在加州增长最快的地区之一专门为黑铁路创建的湿地的管理提供信息。

This study examines differing patterns of population colonization and extinction exhibited by the threatened black rail and the non-threatened Virginia rail inhabiting the same set of wetlands. These two cryptic marsh birds have similar natural histories, but may differ greatly in their ability to fly to new sites based on relationships derived from presence-absence surveys. This study will answer two main questions: Do the patterns of colonization implied from presence-absence data correspond to dispersal behavior? Are the correlates of population turnover the same when the proportion of sites occupied remains constant as when occupancy is increasing or declining? By surveying numerous small wetlands in the Sierra Foothills of California, this research will: compare dispersal distances estimated from turnover to direct measures from telemetry and genetic structure; track colonization of patches after recent extinction events caused by West Nile virus; determine the origin of colonists using genetic and isotope measures to untangle the contributions of short- and long-distance dispersal; and monitor for reoccurrence of West Nile virus by testing blood of all captured rails. A broader impact resulting from this research will be the development of techniques for working with landowners to support conservation of rare species on their land. Private land supports a disproportionate percentage of endangered species and controversies concerning the protection of species under the Endangered Species Act occur. Few field studies are conducted on private property. This study provides a unique opportunity to explore ways of working with private landowners, and for educational outreach through a variety of approaches. The project will integrate research and education by training graduate and undergraduate students, and by offering local landowners, Audubon volunteers, high school students and teachers the chance to experience research in the field with researchers. Results from this project will advance Black Rail conservation by producing important data on dispersal ability and connectivity among regional populations, and informing management of wetlands created specifically for black rails in one of the most rapidly growing regions of California.