Dissertation Research: Quantifying Edge, Behavioral, and Climatic Effects on Survivorship Estimates of an Area-Sensitive Non-Migratory Sparrow

[902226] bolger & morrison住宅开发导致南加州沿海鼠尾草灌木栖息地大面积破碎。鸟类人口统计研究中一个长期存在的问题是，对存活率的估计往往有偏差，因为它们完全来自对有标记的个体的消失的观察，这可能是由于死亡或移民造成的。由于行为因素导致的个体更替，如果纳入成人死亡率估计，将使其偏向向上。本研究询问南加州红冠麻雀（Aimophila ruficeps canescens）在靠近发达边缘的栖息地与栖息地内部区域相比，繁殖和存活率是否降低。在繁殖季节和非繁殖季节，通过在地上和地外重新安置标记个体，重点研究了领地更替动态与存活之间的关系。这些数据与繁殖数据和广泛的栖息地测量相结合，可以测试有关繁殖历史、地点保真度和分散的假设。阐明这些关系可以更有信心地将领土更替归因于分散或死亡。完整的数据集为严格检查个体适应度、局部动态和景观效应之间的关系奠定了基础。这些数据还将揭示繁殖后和出生后的扩散定居模式，以及1998年厄尔尼诺和1999年拉尼娜的不同气候条件可能在多大程度上影响了边缘栖息地的质量。

9902226Bolger & MorrisonResidential development has resulted in extensive fragmentation of the coastal sage scrub habitat in southern California. A long-standing problem in avian demographic studies is that estimates of survivorship are often biased, because they derive solely from observations of disappearance of marked individuals which may occur from either mortality or emigration. Turnover of individuals due to behavioral factors, if subsumed in the adult mortality estimate, would bias it upwards. This study asks whether the Southern California Rufous-crowned Sparrow (Aimophila ruficeps canescens) experiences reduced reproduction and survival in habitat adjacent to developed edges compared to habitat interior areas. It focuses on the relationship between territory turnover dynamics and survivorship by resighting marked individuals both on and off-plot, during the breeding and non-breeding seasons. These data in combination with reproductive data and extensive habitat measures, allows tests of assumptions about breeding history, site fidelity and dispersal. Elucidation of these relationships enables more confident attribution of territory turnover to either dispersal or mortality. The complete data set establishes a foundation for rigorously examining relationships between individual fitness, local dynamics, and landscape effects. These data would also shed light on post-breeding and natal dispersal settlement patterns, as well as the extent to which the disparate climatic conditions of the 1998 El Nino and 1999 La Nina may have affected habitat quality along edges.