Dissertation Research: The Population Biology of Rarity in the Genus Eupatorium

种群生物学的主要目标是确定物种分布和局部丰度的偶然基础。稀有物种代表一种极端情况，因此它们是研究影响丰度因素的有用系统。人们对保护问题的认识不断提高，促使人们对珍稀物种的研究和适当的管理措施产生了额外的动力，但目前还没有一致的理论遗传或生态框架来解决这些问题。本研究将使用紫茎泽兰（稀有）和perfoliatum（常见）来研究与稀有相关的生态和遗传特征。由于遗传漂变，稀有物种的遗传变异较小。群体内和群体间的遗传变异将通过淀粉凝胶电泳进行评估。在稀有物种中也可能出现近交衰退和环境耐受范围有限的现象。将采用田间试验来评价近交抑制的程度。温室实验将用于测量表型可塑性的程度，表型可塑性反过来影响物种的环境耐受性。由于本研究的全面设计，所获得的信息将为稀有性的进化和管理方面提供见解。

The main goal of population biology is to determine the casual basis for species distribution and local abundance. Rare species represent an extreme situation, hence they are a useful system for studying factors that influence abundance. Increasing awareness of conservation issues has generated additional motivation to study cases of rarity and appropriate management practices for rare species, but there is currently no coherent theoretical genetic or ecological framework to address these issues. Eupatorium resinosum (rare) and E. perfoliatum (common) will be used in this study examining ecological and genetic characteristics associated with rarity. Low genetic variation is expected in rare species due to genetic drift. Genetic variation within and among populations will be evaluated by using starch gel electrophoresis. Inbreeding depression and limited range of environmental tolerance are also expected in rare species. A field experiment will be used to evaluate the extent of inbreeding depression. A greenhouse experiment will be used to measure the extent of phenotypic plasticity which in turn influences a species environmental tolerance. Due to the comprehensive design of this study, the information obtained will provide insights into both evolutionary and management aspects of rarity.