Collaborative Research: LTREB: Feedbacks between evolution and demography in severely fragmented prairie populations of the purple coneflower, Echinacea angustifolia

本项目将继续对紫锥花（Echinacea angustifolia）的自然选择进行长期研究。在19世纪初，大草原覆盖了北美的大片地区。从那时起，大约99%的高草草原被摧毁。小块的、孤立的草原仍然保留着丰富的生物多样性，然而在残存的草原上，当地植物灭绝的速度却高得惊人。这个项目将促进对为什么一些种群灭绝而另一些种群持续存在的科学理解。草原种群面临的威胁包括灭火、传粉者减少、近亲繁殖、遗传多样性丧失以及自然选择进化能力下降。该项目建立在对这些生态和遗传过程以及它们之间影响模式草原植物物种的反馈的长期调查基础上。紫色牛角花是草原植物的典型，它的寿命很长，通常是几十年，还有其他特征。这项研究是同类研究中首次阐明一个种群的适应能力。除了推进科学知识和向科学家和土地管理者传播信息外，该项目还将为不同的参与者提供适合他们兴趣和职业阶段的研究经验和培训：明尼苏达州和芝加哥植物园的高中生、大学生、研究生、教师和公民科学家。该项目使用正式的定量遗传方法和常见的花园实验设计来量化适应性、种群分化和近交抑制的加性遗传变异。研究人员将利用aster统计模型分析适应度数据，估计2003年种植的个体达尔文适应度的遗传变异量，其中许多个体在2015年首次开花。其他实验将估计由于兄弟姐妹之间的交配而导致的平均适合度的降低。连同1996年开始的对残余人口的人口普查，这些研究将对人口增长率和进化拯救的可能性作出全面评估。这项研究的一个关键优势是，实验是在一个现实的栖息地进行的，包括金合花与其传粉者和食草动物的相互作用。核心数据集包括连续的个体适应性记录，包括在10个实验和明尼苏达州27个自然草原遗迹中超过17,000种植物的年生存和繁殖。这些数据集将在项目结束时延长至30年，为研究长寿物种的进化和生态过程的相互作用提供了一个难得的窗口。

This project will continue a long-term study of natural selection in the purple coneflower, Echinacea angustifolia. At the beginning of the 1800s, prairie covered a great swath of North America. Since then, about 99% of the tallgrass prairie has been destroyed. The small, isolated patches of prairie that remain harbor great biodiversity, yet rates of local plant extinctions are alarmingly high in remnant prairies. This project will advance scientific understanding of why some populations go extinct and others persist. Threats to prairie populations include fire suppression, declines of pollinators, inbreeding, loss of genetic diversity, and a reduced capacity to evolve by natural selection. This project builds on a long-term investigation of these ecological and genetic processes and feedbacks between them affecting a model prairie plant species. The purple coneflower typifies prairie plants in its long lifespan, often decades, and in other attributes. This study is the first of its kind to illustrate a population's capacity to adapt. In addition to advancing scientific knowledge and disseminating information to scientists and land stewards, this project will provide research experience and training to diverse participants at a level appropriate for their interests and career stage: high school, college, and graduate students, teachers, and citizen scientists in Minnesota and at the Chicago Botanic Garden.The project uses formal quantitative genetic approaches and common garden experimental designs to quantify additive genetic variance for fitness, population differentiation, and inbreeding depression. Researchers will estimate the amount of genetic variation in Darwinian fitness of individuals planted in 2003, many of which flowered for the first time in 2015 using aster statistical models to analyze fitness data. Other experiments will estimate the reduction in mean fitness due to mating between siblings. Together with demographic censuses of remnant populations, started in 1996, these studies will yield comprehensive assessments of population growth rates and the potential for evolutionary rescue. A key strength of the research is that experiments are conducted in a realistic habitat, including interactions of the coneflower with its pollinators and herbivores. The core datasets comprise continuous individual fitness records, including annual survival and reproduction of over 17,000 plants in ten experiments and in 27 natural prairie remnants in Minnesota. These datasets, which will extend up to 30 years by the end of the project, offer a rare window into the interplay of evolutionary and ecological processes of a long-lived species.