Collaborative Research: Controls over Prairie Plant Range Distributions under Future Climate Change

环境科学面临的一个关键挑战是了解气候变化如何与其他干扰因素（如入侵植物物种）相互作用，通过改变本地和入侵物种的范围来影响生物多样性。有压倒性的证据表明，在过去的30年里，随着气候的变化，许多物种已经改变了它们的范围。然而，观测到的范围变化和基于物种分布的当前气候边界的计算机模拟结果，都未能提供足够强的理论基础，对未来变化将如何影响这些分布做出合理的预测。一个机械的方法，融合理论与现场实验，需要真正了解控制范围分布。此外，植物如何扩散还没有包括在范围转移的模型中，除了初步的方式。 然而，分散可能会阻止许多物种对气候变化做出反应，特别是对于那些出现在当今高度破碎的景观中孤立的地方的本土物种。该项目将通过在太平洋西北部300英里气候梯度的三个草原地点进行一项新的气候变化实验来解决这一认识上的差距。它还将使用分子遗传学技术和计算机模型，包括气候对这些植物的生存，繁殖和扩散率的影响，估计历史和最近的代表性草原植物的扩散率。一系列的教育活动将帮助高中生，本科生和研究生发展他们的专业技能。将建立一个网站，重点关注气候变化对区域和全球生物多样性的潜在影响。几个非政府保护组织将成为这项研究的合作伙伴。这项研究将包括三个耦合的任务。(1)一个既定的操纵变暖和降水的研究，是嵌入在一个区域的气候梯度将被用来实验研究气候与当地因素的作用，在控制人口的一个广泛的套件12个本地草和杂类草物种，目前达到北方范围限制在太平洋西北部。人口统计学模型将用于定量确定当地因素的相对效应大小（例如，植物群落组成和土壤变量），区域尺度的气候差异，以及年际气候变化对重点物种的生命率。(2)景观种群遗传学将被用来确定八个焦点物种的景观，面临不同的障碍，由于历史和当代的土地利用和植被，地理扩散障碍，草原栖息地补丁之间的距离扩散概率。(3)前两个组成部分将在太平洋西北部走廊-山谷草原内的三种气候变化情景下的区域景观模拟中加以综合。然后，模拟模型将用于预测焦点物种是否可能在其当前范围的全部或部分灭绝，在未来气候条件下，它们能够在其当前范围之外生存，以及到达这些新的有利栖息地的可能性。景观阻力的增加或减少对通过损失扩散的影响（例如，增加的显影压力）或增益（例如，增加草原恢复）的草原栖息地在未来也将审查。

A key challenge for environmental science is to understand how climate change will interact with other disturbance agents, such as invasive plant species, to impact biodiversity through changes in the range of both native and invasive species. There is overwhelming evidence that many species have shifted their ranges in the past 30 years as the climate has changed. However, observed range shifts and the results of computer modeling based on the current climatic boundaries of species distributions, both fail to provide a strong enough theoretical foundation for making sound predictions of how future changes will affect these distributions. A mechanistic approach that fuses theory with field experimentation is required to truly understand controls over range distributions. In addition, how plants disperse has not been included in models of range shifts except in rudimentary ways. Yet dispersal may keep many species from responding to climate change, especially for those native species that occur in isolated pockets of the highly fragmented landscapes of today. This project will address this gap in understanding by using a novel climate change experiment at three prairie sites across a 300 mile climate gradient in the Pacific Northwest. It will also estimate historical and recent rates of dispersal of representative prairie plants using molecular genetics techniques, and computer models that include the effects of climate on the survival, reproduction, and rates of dispersal of these plants. A range of education activities will help high school, undergraduate, and graduate students to develop their professional skills. A web site will be developed to focus on the potential impacts of climate change on regional and global biodiversity. Several nongovernmental conservation organizations will be partners in the research.This research will be comprised of three coupled tasks. (1) An established manipulative warming and precipitation study that is embedded within a regional climate gradient will be used to experimentally examine the role of climate versus local factors in controlling the demography of a broad suite of 12 native grass and forb species that currently reach northern range limits in the Pacific Northwest. Demographic models will be used to quantitatively determine the relative effect sizes of local factors (e.g., plant community composition and soil variables), regional-scale climate differences, and interannual climate variability on the vital rates of the focal species. (2) Landscape population genetics will be used to determine dispersal probabilities of eight of the focal species in landscapes that face different barriers to dispersal due to both historical and contemporary land use and vegetation, geographic dispersal barriers, and distance between prairie habitat patches. (3) The first two components will be synthesized in a regional landscape simulation under three climate change scenarios within interior-valley prairies in the Pacific Northwest. The simulation model will then be used to predict whether the focal species are likely to go extinct in all or parts of their current ranges, where they are capable of surviving outside of their current ranges under future climatic conditions, and the probability of reaching these new favorable habitats, if they exist. The effects of increased or decreased landscape resistance to dispersal through loss (e.g., increased development pressure) or gain (e.g., increased prairie restoration) of prairie habitat in the future will also be examined.