DISSERTATION RESEARCH: Thrice through Beringia? Unraveling the evolution of North American pikas

俄罗斯和阿拉斯加之间的无冰走廊，被称为白令陆桥，促进了跨大陆物种的交流，并在上一个冰河时期为许多物种提供了避难所。因此，它是检验有关许多物种的传播和生存理论的重要场所。该地区的气候变化迅速，据预测，北极地区近期的变暖趋势最为强烈。小型哺乳动物，如有领鼠兔，提供了有关气候变化影响的重要信息。有圈鼠兔只在阿拉斯加和加拿大西北部的斜坡上发现。这是北美仅有的两种鼠兔中的一种，它们的活动范围远比其他种类的鼠兔要北。将鼠兔的化石记录与遗传数据进行对比，表明有项圈的鼠兔近期活动范围缩小，随后迅速扩大。这与有项圈鼠兔从南方的避难所而不是从俄罗斯进入其北部栖息地的观点是一致的。该奖项支持阿拉斯加费尔班克斯大学一位博士候选人的研究。该研究对理解北极和亚北极生态系统中谱系的持续和进化具有重要意义。它将有助于确定北部地区的动物更替率，并区分偶然事件和反复出现的进化趋势。该项目还为了解气候变化对标志性高山哺乳动物种群特征的长期影响提供了重要的经验背景。

The ice-free corridor between Russia and Alaska, known as Beringia, has facilitated transcontinental species exchange and provided a refugium for many species during the last ice age. It is therefore an important arena for testing theories regarding dispersal and survival of many species. Climate has shifted rapidly in this region, and recent warming trends are predicted to be strongest in the Arctic. Small mammals, such as the collared pika, provide important information on the effects of climate change. Collared pikas are found only on talus slopes in Alaska and northwest Canada. This is one of only two species of North American pikas, and their range is far to the north of the other species. When the fossil record of pikas is contrasted with genetic data, a history of recent range contraction and subsequent rapid expansion is suggested for collared pikas. This is consistent with the idea that collared pikas entered their northern habitat from refugia in the south, and not from Russia.This award supports the research of a doctoral degree candidate at the University of Alaska, Fairbanks. The study has implications for understanding the persistence and evolution of lineages in arctic and subarctic ecosystems. It will help determine the rate of faunal turnover in northern regions, and distinguish between chance events and recurrent evolutionary trends. This project also provides an important empirical context for understanding the long-term effects of climate change on the demographics of an iconic alpine mammal.