Collaborative Research: How Mountains Maintain Biodiversity: A Multidisciplinary Characterization of a Pleistocene Refugium in the Interior Pacific Northwest

了解物种对历史气候变化的反应可以为预测未来气候变化对生态系统的影响提供信息。山脉拥有广泛的栖息地和多样化的物种，这是自上一个冰河时代以来重大气候变化的历史所塑造的。这些变化导致植被迅速而重大的变化，例如从冻土带向森林的转变。在原本不适宜居住的气候时期，山区也被认为是生物多样性的避难所。该项目将描述爱达荷州北部陡峭地形中的冰河时代避难所的特征，那里可能藏匿着种类繁多的动植物物种，从而阐明山区地形如何通过重大气候变化来缓冲种群。该项目侧重于北部针叶林中的两种主要树种(西部红柏和山地铁杉)，将综合三种方法，以利用它们在推断过去种群规模和位置方面的优势。首先，尖端的DNA测序方法将揭示物种迁徙路径的遗传足迹，并测试避难所的存在。其次，新的花粉和大型化石的古生态记录将揭示过去5万年来最冷时期的区域植物种类组成和气候。第三，对复杂山区的历史气候的模拟将与关于每个物种的生理耐受性(例如，耐寒性)的信息相结合，以揭示该地区最有可能的避难所位置。该项目的跨学科方法为培训下一代生物地理学家提供了机会，他们将需要这些传统上独特的遗传学、古生物学和景观建模方面的技能来预测未来气候变化的生态影响。研究生将在遗传学、古生态学和景观生态学实验室之间轮换，以实现这一培养目标。此外，还将为高中教师举办课程研讨会，用于开发动手活动的课程。

Understanding the responses of species to historical climate shifts can inform predictions of the future impacts of climate change on ecosystems. Mountains contain a wide range of habitats and diverse species, which have been shaped by a history of major climate changes since the last ice age. These changes have resulted in rapid and major changes in vegetation such as shifts from tundra to forest. Mountainous regions are also thought to harbor biodiversity in refugia during otherwise inhospitable climate periods. This project will characterize an ice-age refugium in steep terrain in northern Idaho that may have harbored a wide diversity of plant and animal species, and thus illuminate how mountainous terrain may buffer populations through major climate changes. Focusing on two dominant tree species in northern conifer forests (western redcedar and mountain hemlock), this project will integrate three methodological approaches to leverage their strengths in inferring past population sizes and locations. First, cutting-edge DNA-sequencing methods will reveal the genetic footprints of species' migration pathways and test for the existence of refugia. Second, new paleoecological records of pollen and macrofossils will reveal the regional plant species composition and climate during the coldest periods in the past 50,000 years. Third, simulations of historical climate across the complex mountain landscape will be combined with information on the physiological tolerances of each species (e.g., cold hardiness), to reveal the most likely locations of refugia within this region. The interdisciplinary approach of this project provides an opportunity to train the next generation of biogeographers, who will need these traditionally distinct skill sets in genetics, paleontology, and landscape modeling to forecast ecological impacts of future climate change. Graduate students will rotate among genetics, paleoecology and landscape ecology labs to achieve this training goal. In addition, a curriculum workshop will be conducted for high school teachers, and used to develop lessons for hands-on activities.