Collaborative Research: Mechanisms of Population Regulation in Migratory Birds

本研究旨在测试和评估决定北美迁徙鸣禽种群规模的机制（即过程）。这项研究将有助于理解为什么一些物种目前出现了数量下降。这项工作的重点是在新罕布什尔州中北部的哈伯德布鲁克实验森林中繁殖黑喉蓝林莺（树喉蓝林莺）。通过监测和实验研究，我们将量化密度依赖和地点依赖两种类型的种群调控的发生和强度。每种类型都能够产生关于种群规模的负反馈。一项测试将涉及评估实验性减少当地人口密度的影响，而监测将审查生境质量如何影响鸟类生存和繁殖。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。这些措施的能力，单独和集体，以预测地域特定的繁殖，生存和分散这些物种在广阔的空间和高度尺度将被检查。来自这些研究的数据将用于计算机模拟模型，以比较两个潜在重要的监管过程的监管强度。模型预测和分析将有助于识别、评估和整合决定该候鸟物种种群变化和丰度的因素和过程。该研究成果不仅有助于建立生态学的基础理论，而且对候鸟的管理具有直接的应用价值，其中一些候鸟的数量正在减少，值得关注。

9629488 Holmes 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.