Comparative phylogeography of three woody species to infer vegetation history of the Patagonian steppe

巴塔哥尼亚是南美洲最南端的一个地区，到目前为止，很少有人对植物进行地理学研究。因此，植被历史和生物多样性热点的知识是稀缺的。两项早期的研究发现，在巴塔哥尼亚草原的四种草本植物中，有非常相似的地理分布模式，巴塔哥尼亚草原是安第斯山脉以东巴塔哥尼亚的主要植被单位。在这个项目中，将分析该植被单元的三个特征木本物种的生态地理。我们将使用叶绿体基因组序列和核微卫星位点作为分子标记来检测遗传多样性的地理模式。此外，我们将使用环境生态位建模来表征生态位参数和推断过去的物种分布。这项研究的主要目的是推断，如果类似的地理模式表明，这些物种的共同更新世的历史，尽管他们的生态差异，或者如果物种的反应不同，过去不断变化的气候。通过将本研究的结果与早期对巴塔哥尼亚草原分类群的分析结果相结合，将有可能对该植物群落的植被历史有一个总体的了解，特别是如果草原植被作为一个单位改变了其分布，或者草原的组成随着更新世气候的变化而反复变化。

Patagonia, the southern-most part of South America, is an area where up to now very few phylogeographic studies of plants have been conducted. Thus, knowledge of vegetation history and hotspots of biodiversity is scarce. Two earlier studies found very similar phylogeographic patterns in four herbaceous species of the Patagonian steppe, the dominant vegetation unit of Patagonia east of the Andes. Within this project the phylogeography of three characteristic woody species of this vegetation unit will be analyzed. We will use sequences of the chloroplast genome and nuclear microsatellite loci as molecular markers to detect geo¬graphic patterns of genetic diversity. In addition we will use environmental niche modeling to characterize niche parameters and infer past species distribution. The main objective of this study is to infer if similar phylogeographic patterns indicate a common Pleistocene history of these species despite their ecological differences, or if the species reacted differently to past changing climate. By integrating the results of this study with that of the few earlier analyses of Patagonian steppe taxa it will be possible to reach a general understanding of the vege¬tation history of this plant community, particularly if steppe vegetation shifted its distribution as a unit or if the composition of the steppe changed repeatedly with Pleistocene climate changes.