Collaborative Research: Mechanisms of Population Regulation in Migratory Birds

9633522罗登豪斯这项研究旨在测试和评估决定北美候鸟种群数量的机制(即过程)。这项研究将有助于理解为什么一些物种目前呈现出种群数量下降的现象。这项工作的重点是新汉普郡中北部哈伯德布鲁克实验森林中的黑喉蓝莺(Dendroica Caerulescens)的繁殖种群。通过监测和实验研究，我们将量化两种类型的种群调控的发生和强度，即密度依赖和场地依赖。每种类型都能对种群数量产生负反馈。其中一项测试将评估实验性减少当地种群密度的效果，而监测将检查栖息地质量如何影响鸟类的生存和繁殖。栖息地质量将根据食物丰度、天气、捕食者丰度以及植被组成和结构来定义。将考察这些措施单独和集体预测这些物种在广泛的空间和高度尺度上特定地区的繁殖、生存和扩散的能力。这些研究的数据将被用于计算机模拟模型，以比较这两个潜在重要监管过程的监管力度。模型预测和分析将有助于识别、评估和整合决定这种候鸟物种种群变化和丰度的因素和过程。这项研究的结果不仅将有助于生态学的基本理论，还将对候鸟的直接管理应用，其中一些候鸟的数量正在下降，并受到保护的关注。

9633522 Rodenhouse This research is designed to test and evaluate the mechanisms (i.e., processes) determining population size in North American migratory songbirds. The study will help in understanding why some species are currently showing population declines. The work focuses on breeding populations of Black-throated Blue Warblers (Dendroica caerulescens) in the Hubbard Brook Experimental Forest in north central New Hampshire. Through monitoring and experimental studies, we will quantify the occurrence and strength of two types of population regulation, namely density-dependence and site-dependence. Each type is capable of generating negative feedbacks on population size. One test will involve evaluating the effects of experimental reductions of local population density, while monitoring will examine how habitat quality influences bird survival and reproduction. Habitat quality will be defined in terms of food abundance, weather, predator abundance, and vegetation composition and structure. The ability of these measures, singly and collectively, to predict territory-specific reproduction, survival, and dispersal of these species over broad spatial and altitudinal scales will be examined. Data from these studies will be employed in computer simulation models for comparisons of the regulatory strength of the two potentially important regulatory processes. Model projections and analyses will help to identify, assess, and integrate the factors and processes determining population changes and abundances of this migratory bird species. Results of this research will contribute not only to basic ecological theory, but also will have direct management applications for migratory songbirds, some of which are declining in abundance and are of conservation concern.