Demography and Fragmentation in an Avian Species: A Genetic Analysis

这个项目调查了在稀有和正在消失的栖息地中成为极端生态专家的遗传后果。佛罗里达灌木鸦是一种受到联邦政府威胁的鸟类，仅限于一个正在被人类迅速灭绝的栖息地。22年来对有标记种群的详细研究表明，这些松鸦有一种不同寻常的社会制度，很少会离开它们孵化的几个地区。这种非常有限的扩散可能会在短距离内导致基因变化的快速发展，特别是在高度分散的栖息地内。将使用各种复杂的遗传技术(DNA‘指纹’和测序)来检查地方和区域范围内的遗传变异。具体目标是：1)确认只在每个领土上的交配对进行繁殖(即，很少或没有域外受精)；2)测试近亲繁殖水平是否影响终生生殖性能；3)比较距离、栖息地隔离程度和种群大小对遗传变异和分化的影响，以及4)检验这些遗传效应是否与长期人口统计数据预测的结果相符。除了理论应用，这项研究还将通过展示栖息地丧失和碎片化如何影响生态专门化物种的基因构成来进一步保护生物多样性。

This project investigates the genetic consequences of being an extreme ecological specialist in a rare and vanishing habitat. The Florida Scrub Jay is a federally Threatened bird species, restricted to a habitat that is rapidly being eliminated by man. Twenty-two years of detailed study of a marked population have shown that these jays have an unusual social system, and rarely move more than a few territories from where they were hatched. This very limited dispersal may result in rapid development of genetic changes over short distances, especially within a habitat that is highly fragmented. A variety of sophisticated genetic techniques (DNA 'fingerprinting' and sequencing) will be used to examine genetic variation at both local and regional scales. Specific goals are to: 1) confirm that reproduction takes place only by the mated pair on each territory (i.e., extra-pair or extra-territorial fertilizations are rare or absent); 2) test whether levels of inbreeding affect lifetime reproductive performance; 3) compare the effects of distance, degree of habitat isolation, and population size on genetic variation and differentiation, and 4) test whether these genetic effects match those predicted by long-term demographic data. Besides its theoretical applications, this study will further the protection of biodiversity by showing how habitat loss and fragmentation affect the genetic makeup of ecologically specialized species.