DISSERTATION RESEARCH: Evolutionary Genomics of Range Limits in an Endemic Salamander

该项目将利用美国东部特有的蝾螈对物种分布范围限制的主要解释进行实证检验。大多数物种的地理分布并不能用明显的扩散障碍或环境耐受性的限制来解释，这使得理解范围限制成为生态学和进化生物学的中心问题。此外，了解限制范围的因素是保护的当务之急，因为气候变化，外来物种入侵和栖息地改变影响了地球上大多数物种的范围。更好地理解限制物种的机制？由于全球气候变化，有灭绝危险的物种可以确定。反过来，管理可以集中在保护区的目标位置或选择物种进行管理迁移。总的来说，拟议的研究应该有广泛的基础，以及实际的影响，因为在物种的范围限制的兴趣是广泛的整个生态，进化和保护community.Although范围限制假说是有充分的理论基础，实证检验已经落后。这种综合的方法将提供一个了解的机制，限制物种的地理分布，并导致预测物种的框架？灭绝风险溪畔蝾螈（Ambystoma barbouri）在肯塔基州、俄亥俄州和印第安纳州有一个有限的连续分布区。在物种分布范围内，边缘种群的遗传多样性和有效种群规模通常低于分布中心的种群，这可能会阻止分布范围边缘的地理扩张。本研究将使用人口基因组学，景观遗传学和实验场研究相结合，以确定（1），如果不对称的基因流从核心到边缘限制当地的适应和范围的扩展，（2）如果增加栖息地阻力在物种边缘阻止范围的扩展。预计这些多个假设都可能至少在某种程度上对范围限制有所贡献。

This project will provide empirical tests of the major explanations for limits on species' range using a salamander endemic to the eastern United States. Most species' geographic distributions are not explained by obvious barriers to dispersal or limits on environmental tolerances, making understanding range limits a central question in ecological and evolutionary biology. In addition, understanding the factors that limit ranges is an urgent priority for conservation as climate change, exotic species invasions, and habitat alterations influence the ranges of the majority of Earth's species. With a better understanding of the mechanisms limiting species? ranges, species at risk of extinction due to global climate change can be identified. In turn, management can focus on targeting locations for protected areas or choosing species for managed translocation. Overall, the proposed research should have broad basic, as well as practical, implications because interest in species' range limits is widespread throughout the ecological, evolutionary, and conservation community.Although range limit hypotheses are well-grounded in theory, empirical tests have lagged behind. This integrative approach will provide an understanding of the mechanisms that limit species' geographic distributions and lead to a framework for predicting species? extinction risk. The streamside salamander (Ambystoma barbouri) has a restricted continuous range in Kentucky, Ohio, and Indiana. Within the species' range, edge populations generally have lower genetic diversity and effective population sizes than populations in the center of the distribution which may prevent geographic expansion at the range edges. This study will use a combination of population genomics, landscape genetics, and an experimental field study to determine (1), if asymmetric gene flow from core to edge constrains local adaptation and range expansion, and (2) if increased habitat resistance at the species edge prevents range expansion. It is expected that these multiple hypotheses may all contribute to range limits, at least to some extent.