DISSERTATION RESEARCH: Genetic Diversity in Different Forms of Rarity: Computer Models and Empirical Data from Lomatium (Apiaceae)

0073137索尔蒂斯和吉特森纳最近的估计表明，超过33,000种植物(约.1/8的地球植物区系是稀有的，随着人类活动继续侵蚀栖息地，这个数字肯定会增加。在美国，四分之一的植物物种被认为是稀有物种。大多数保护工作都以类似的方式对待稀有物种，假定它们具有相似的遗传和生态特征。这种稀有观点掩盖了稀有物种之间的生物差异，阻止了有关稀有的一般原则的出现，并可能阻碍保护努力。相反，一些研究人员根据地理范围、每个地点的种群大小和特定的栖息地要求，识别出不同形式的稀有物种。例如，一个物种出现在从华盛顿到加利福尼亚州的罕见土壤类型上，尽管它的活动范围超过1000英里，但它可能被认为是“稀有”的；相比之下，一个物种出现在俄勒冈州中部山脊顶的五个地点，每个地点都有数千只个体，也被认为是“稀有”的。这项研究是对不同形式的稀有物种之间的遗传差异进行的研究，使用计算机模拟和来自欧芹和胡萝卜科植物Lomatium(沙漠欧芹)的数据。不同类型的稀有物种和相关广布物种的叶片样本将从自然栖息地采集。这些样本将使用各种遗传标记和统计分析进行分析。这项研究解决了几个国家和联邦列入名单的珍稀植物物种的紧迫保护需求，并将提供用于管理这些物种的遗传数据。更重要的是，这项工作将提高生物学家对稀有物种的理解，对不同类型稀有物种的遗传特征进行概括，使保护生物学更具预测性，并有助于改进其他稀有物种的保护和管理计划。

0073137 Soltis and GitzendannerRecent estimates indicate that over 33,000 plant species (approx. 1/8 of the Earth's flora) are rare, and this number will certainly increase as human activities continue to erode habitat. In the U.S., one quarter of all plant species are considered rare. Most conservation efforts treat rare species similarly, assuming similar genetic and ecological characteristics. This view of rarity masks biological differences among rare species, prevents the emergence of general principles about rarity, and may hinder conservation efforts. Some researchers have instead recognized different forms of rarity, based on geographic range, population size in each location, and specific habitat requirements. For example, a species that occurs on a rare soil type scattered infrequently from Washington to California may be considered "rare", despite the fact that its range spans more than 1000 miles; in contrast, a species that occurs at five sites along a ridge top in central Oregon, with thousands of individuals at each site, is also considered "rare." This research is a study of the genetic differences among different forms of rare species, using both computer simulations and data from the plant genus Lomatium (desert parsley), of the parsley and carrot family. Leaf samples of different types of rare species and of related widespread species will be collected from natural habitats. These samples will be analyzed using a variety of genetic markers and statistical analyses.The research addresses the immediate conservation needs of several State- and Federally-listed rare plant species and will provide genetic data for use in managing these species. More importantly, the work will improve biologists' understanding of rare species, formulate generalizations about the genetic features of different types of rare species, make conservation biology more predictive, and contribute to improved conservation and management plans for other rare species.