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

9902226 Bolger&Amrison住宅开发导致南加州沿海鼠尾草灌木丛栖息地的广泛碎片化。鸟类人口统计学研究中一个长期存在的问题是，对鸟类存活率的估计往往是有偏见的，因为它们完全是根据对标记个体消失的观察得出的，这种消失可能是由于死亡或迁徙造成的。由于行为因素导致的个体更替，如果计入成人死亡率估计，则会使估计结果偏高。这项研究询问，与栖息地内部地区相比，南加州棕冠麻雀是否在靠近发达边缘的栖息地经历了繁殖和生存减少的情况。在繁殖和非繁殖季节，通过重新观察被标记的个体，重点研究了区域周转动态和生存之间的关系。这些数据与繁殖数据和广泛的栖息地测量相结合，可以测试关于繁殖历史、地点保真度和扩散的假设。对这些关系的阐明使人们能够更有把握地将领土周转归因于分散或死亡。完整的数据集为严格检查个人健康、局部动态和景观效果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扩散的定居模式，以及1998年厄尔尼诺和1999年拉尼娜不同的气候条件可能在多大程度上影响边缘的栖息地质量。

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.