Phylogeography, speciation and conservation genetics of patagonian fishes

我们的目的是研究巴塔哥尼亚本地鱼类的比较系统地理学。南安第斯山脉的隆升始于中新世（约23mya），分离了东西流动的排水系统，并影响了相关生物群的系统地理格局。由此产生的系统地理格局随后受到更新世（1.8 MYA - 10,000 BP）反复出现的冰期和间冰期以及火山作用的影响。在末次盛冰期，从南纬35度到56度，覆盖了巴塔哥尼亚安第斯山脉1800公里的冰盖。这片冰原到达南纬42度的安第斯山脉（太平洋）以西的大陆架边缘。因此，巴塔哥尼亚动植物的遗传多样性可能反映了一种影响层次，更新世和全新世期间气候变化和火山活动的分化模式分层在安第斯造山运动产生的古代分化足迹上。我们将集中讨论galaxidae的系统地理学，galaxidae是一组在巴塔哥尼亚以三个广泛分布的物种（galaxas platei， G. maculatus和Aplochiton zebra）为代表的鱼类，以及其他地理分布更有限的鱼类。platei是一种内陆物种，存在于冰川后湖泊的深水中。斑纹斑羚和斑马是小型的沿海物种，斑纹斑羚表现为内陆和双栖形式。系统地理模式将通过线粒体和核DNA位点在三个物种之间进行比较。应用统计系统地理学和聚结方法对生态系统内不同物种的遗传数据进行分析，将为生态群落的进化提供有价值的见解。巴塔哥尼亚鱼类动物群的多样性受到20世纪初引进的鲑鱼的竞争和捕食的威胁，最近和更严重的是，受到逃逸的水产养殖鲑鱼的威胁，其影响预计将随着该地区水产养殖业的不断扩大而增加。我们的研究将证明对基于知识的保护和管理优先事项的发展是有用的。

Our objective is to examine the comparative phylogeography of the native fishes of Patagonia. The uplift of the southern Andes beginning in the Miocene (ca. 23 MYA), separated east and west flowing drainage systems and influenced the phylogeographic patterns of the associated biota. The resulting phylogeographic patterns were subsequently affected by the recurring glacial and interglacial periods of the Pleistocene (1.8 MYA - 10,000 BP) and by volcanism. During the Last Glacial Maximum an ice sheet covered the Patagonian Andes along 1800 km from Lat. 35ºS to 56ºS. This ice sheet reached the edge of the continental shelf west of the Andes (Pacific) south of Lat. 42ºS. Genetic diversity for the Patagonian flora and fauna might therefore be expected to reflect a hierarchy of influences, with patterns of divergence from climate change and volcanisms during the Pleistocene and Holocene layered onto ancient divergence footprints produced by the Andean orogeny. We will focus on the phylogeography of the Galaxiidae, a group of fish represented in Patagonia by three widespread species: (Galaxias platei, G. maculatus, and Aplochiton zebra) and others of more restricted geographic distribution. G. platei is a landlocked species present in the deep waters of postglacial lakes. G. maculatus and A. zebra are small littoral species with G. maculatus exhibiting landlocked and diadromous forms. Phylogeographic patterns will be compared across the three species using mitochondrial and nuclear DNA loci. The application of statistical phylogeographic and coalescent methods on genetic data collected from various species within ecosystems will provide valuable insight into the evolution of ecological communities. The diversity of the Patagonian fish fauna is threatened by competition and predation by salmonids introduced during the early twentieth century, and more recently and more critically, by escaped aquaculture salmon, the influence of which is expected to increase with the ever expanding aquaculture industry in the region. Our research will prove useful for the development of knowledge based conservation and management priorities.