Phylogenetic Systematics of Lysipomia: Speciation and Biogeographical Studies in Andean Paramo

对安第斯山脉帕拉莫和普纳山脉属的系统发育研究为探索热带高海拔环境的进化过程提供了独特的机会。艾尔斯博士正在研究安第斯山脉的铃兰科植物Lysipomia属，目前被认为包括大约30种“缓冲”植物。两种分布广泛，有许多已命名的、地理上受限制的亚种和变种。其余的物种表现出很少或没有种下变异，分布范围极窄，许多特有于单个山脊顶部或火山锥。这些特有物种遍布安第斯山脉，但物种多样性最大的是在厄瓜多尔和秘鲁，位于安第斯山脉北部一个主要地质分界线的两侧，即皮乌拉分水岭或万卡班巴洼地。采用现代分子和传统形态特征的系统发育研究将测试该地质屏障及其相关的近期气候变化是否在Lysipomia的进化史中发挥了重要作用。只有在物种起源和灭绝的已知变化模式的背景下，才能研究进化变化的机制或过程。艾尔斯博士在一项研究计划拨款中开始了一项分子（基于dna的）和形态学研究，研究一组高海拔“缓冲”植物的多样化模式，与它们在安第斯山脉北部的地理分布有关。野外采集植物，结合实验室叶绿体DNA突变研究和植物标本室形态特征研究，将有助于深入了解物种分化模式以及地理屏障和传播途径的作用。

Phylogenetic studies of genera restricted to the Andean paramo and puna provide a unique opportunity to explore evolutionary processes in tropical, high elevation environments. Dr. Ayers is studying the Andean plant genus Lysipomia of the Campanulaceae family, currently thought to comprise about 30 species of "cushion" plants. Two species are widespread and have many named, geographically restricted subspecies and varieties. The remaining species show little or no infraspecific variation and have extremely narrow ranges, with many endemic to a single ridge top or volcanic cone. These endemics occur throughout the Andes, but the greatest species diversity is found in Ecuador and Peru on both sides of a major geologic division of the northern Andes known as the Piura Divide or the Huancabamba Depression. Phylogenetic studies employing modern molecular and traditional morphological characters will test whether this geologic barrier and recent climatic changes associated with it have played an important role in the evolutionary history of Lysipomia. %%% Mechanisms or processes of evolutionary change can be studied only against the background of known patterns of change, in the origin and extinction of species. Dr. Ayers in a research planning grant begins a molecular (DNA-based) and morphological study of the patterns of diversification in a group of high-elevation "cushion" plants, in relation to their geographical distribution in the northern Andes. Field work to make plant collections combined with laboratory study of chloroplast DNA mutations and herbarium study of morphological features will provide insight into patterns of species divergence and the role of geographical barriers and dispersal routes.