DISSERTATION RESEARCH: An Experimental Demographic Approach to Exotic Plant Success: Cynoglossum Officinale in its Native and Introduced Ranges

生态学中的一个中心谜团是关于一些在原生范围内稀有的外来植物是如何在它们被引入的地方获得惊人的高密度的。这项研究通过对北美西部引进的杂草Houndstongue(羊舌兰)的研究来研究这个问题，该杂草在蒙大拿州的引种范围和在德国的原生范围都是如此。这项研究包括两个部分。首先，通过对这两个范围内植物的长期人口统计监测，将量化每个范围内最限制猎犬种群增长的生活期(即种子、幼苗、成年植物)。其次，将在原生和引进范围内进行平行实验，以探索可能有助于猎犬在北美获得更大成功的三个因素的相对作用：干扰增加，植物对这种干扰的反应比在欧洲更大；逃避专业昆虫食草动物；以及在引入范围内开花多次的能力，而不是在原生范围内只开一次花。虽然已经提出了许多假说来解释是什么允许外来植物主导本土植物群落，但几乎没有严格的实验测试。这项研究将为这些机制提供为数不多的定量测试之一。此外，通过确定哪些生活期限制了种群增长，这项工作还将为控制这种有害杂草的管理工作提供指导。

A central mystery in ecology concerns how some exotic plants that are rare in their native range attain staggeringly high densities where they have been introduced. This research examines this problem with a study of an introduced weed in western North America, houndstongue (Cynoglossum officinale), both in its introduced range in Montana and its native range in Germany. The research involves two components. First, through long-term demographic monitoring of plants in both ranges, the life stages (i.e. seeds, seedlings, adult plants) that most limit population growth of houndstongue in each range will be quantified. Second, parallel experiments in the native and introduced range will be used to explore the relative roles of three factors that may contribute to houndstongue's increased success in North America: increased disturbance and a greater response of the plant to this disturbance than in Europe; escape from specialist insect herbivores; and an ability to flower several times in the introduced range compared to only once in the native range. While many hypotheses have been proposed to explain what allows exotic plants to dominate native plant communities, few rigorous experimental tests exist. This research will provide one of the few quantitative tests of these mechanisms. In addition, by identifying which life stages limit population growth, the work will also provide guidance to management efforts to control this noxious weed.