LTER: Long-Term Research on Grassland Dynamics- Assessing Mechanisms of Sensitivity and Resilience to Global Change

LTER：草地动态长期研究——全球变化敏感性和复原力评估机制

• 批准号: 1440484
• 负责人: Jesse Nippert
• 金额: $ 676.2万
• 依托单位: Kansas State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2014
• 资助国家: 美国
• 起止时间: 2014-11-01 至 2021-10-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1440484&HistoricalAwards=false
• 关键词: LTER; Long; Term; Research; Grassland

Grasslands cover more of the Earth's land than any other major vegetation type, and temperate grasslands are among the most endangered ecosystems on the planet. Threats to grasslands include land use changes, expansion of woody species, invasion by exotic species, and changes in climate and nutrient deposition. In the highly productive tallgrass prairies of North America, changes in fire, grazing and climate are especially critical. Conserving the biological diversity and ecosystem services provided by these grasslands, while also managing them for sustainable production, requires a comprehensive understanding of how these ecosystems will respond to current and future environmental and land-use changes. Decades of research at the Konza Prairie LTER site are producing a rich and detailed understanding of how environmental and land-use changes independently and interactively affect the structure and function of grasslands and associated groundwater and streams. New research will build on this foundation of long-term experiments and measurements to understand causes and consequences of ecological change in tallgrass prairie. This will contribute to the sustainable management, conservation and, restoration of terrestrial and aquatic resources in tallgrass prairies, and other grasslands globally. Research on restoration of grasslands is particularly timely because of the widespread loss and degradation of prairies and other grasslands. The impacts of Konza Prairie research will extend far beyond the site, through engagement with stakeholders and management and conservation agencies. Researchers will disseminate findings through the Flint Hills Discovery Center, which educates civic, professional, conservation, and governmental agencies about the tallgrass prairie and the Flint Hills region of Kansas. The Konza Environmental Education Program will engage over 1,000 school students annually in hand-on science education activities. The Konza LTER program will conduct an annual Summer Teacher's Workshop provides to train elementary and secondary teachers, and a summer field biology course at a local high school. The project will support community education through collaboration with the Kansas Association for Conservation and Environmental Education, Flint Hills Discovery Center, Manhattan Boys and Girls Club, and United School District 383. The research is organized around four major themes (land-use change, climatic variability, altered biogeochemical cycles, and restoration ecology) and builds on a 30-yr foundation of long-term experiments and measurements in terrestrial and aquatic grassland ecosystems. Watershed- and plot-level experiments at Konza Prairie have altered fire, grazing, climate, nutrient availability in ways that have created a range of different ecological states and legacies. New research will couple ongoing long-term observations and experiments with new studies to (1) test and refine conceptual and theoretical models of community and ecosystem change, and (2) provide new insights into the mechanisms underlying ecological responses to critical environmental and land-use changes. This research will a) measure responses to long-term manipulation of fire, grazing, climate, and nutrients, b) test novel causative factors in additional experiments, c) determine the ability of bison grazing to develop and maintain alternate stable vegetation states, and d) cease or alter some long-term experimental manipulations (water or nutrient availability) to assess ecological legacy effects and feedbacks. Fire and grazing studies will address fundamental questions regarding top-down and bottom-up controls of ecological processes, and effects of heterogeneity on biodiversity and ecosystem processes. Studies of woody plant encroachment, climate change, and chronic N enrichment will address three of the most critical changes occurring in grasslands worldwide. Researchers will use intermediate fire return treatments too ask whether observed shrub encroachment under intermediate fire intervals represents a new stable state. Restoration studies will test fundamental ecology theories on controls of plant diversity and community assembly, while building a foundation for more effective strategies for restoring grasslands and conserving grassland biodiversity. This research is conceptually integrated through a common theme of sensitivity and resilience of grasslands to natural and anthropogenically-altered drivers. When these diverse and creative research projects are taken together, this long-term project is poised to address major global change phenomena and to test fundamental ecological theory related to non-linear dynamics and alternate stable states, productivity-diversity and disturbance-stability relationships, top-down vs. bottom-up regulation of ecological processes, food web dynamics, and responses to environmental heterogeneity.

草原覆盖地球的土地比任何其他主要植被类型都多，温带草原是地球上最濒危的生态系统之一。对草地的威胁包括土地利用的变化、木本物种的扩张、外来物种的入侵以及气候和养分沉积的变化。在北美高产的高草草原上，火灾、放牧和气候的变化尤其重要。要保护这些草原提供的生物多样性和生态系统服务，同时还要管理它们以促进可持续生产，就需要全面了解这些生态系统将如何应对当前和未来的环境和土地使用变化。在Konza Prairie LTER站点进行的数十年研究正在对环境和土地利用变化如何独立和相互作用地影响草原和相关地下水和溪流的结构和功能产生丰富而详细的了解。新的研究将建立在长期实验和测量的基础上，以了解高草草原生态变化的原因和后果。这将有助于高草草原和全球其他草原的陆地和水生资源的可持续管理、保护和恢复。由于大草原和其他草原的广泛损失和退化，恢复草原的研究特别及时。Konza Prairie研究的影响将远远超出现场，通过与利益相关者和管理和保护机构的接触。研究人员将通过弗林特山探索中心传播研究结果，该中心为公民、专业、保护和政府机构提供有关高草草原和堪萨斯州弗林特山地区的教育。Konza环境教育计划每年将有1，000多名学生参与动手科学教育活动。Konza LTER计划将每年举办一次暑期教师研讨会，培训小学和中学教师，并在当地高中开设暑期野外生物学课程。该项目将通过与堪萨斯保护和环境教育协会、弗林特山发现中心、曼哈顿男孩女孩俱乐部和联合学区383的合作来支持社区教育。该研究围绕四个主要主题（土地利用变化，气候变化，改变地球化学循环和恢复生态学）进行组织，并建立在陆地和水生草原生态系统长期实验和测量的30年基础上。在Konza Prairie进行的流域和地块级实验改变了火、放牧、气候和养分供应，从而创造了一系列不同的生态状态和遗产。新的研究将把正在进行的长期观察和实验与新的研究结合起来，以（1）测试和完善社区和生态系统变化的概念和理论模型，（2）为关键环境和土地利用变化的生态响应机制提供新的见解。本研究将a）测量对火、放牧、气候和养分的长期操纵的反应，B）在额外的实验中测试新的致病因素，c）确定野牛放牧发展和维持交替稳定植被状态的能力，以及d）停止或改变一些长期实验操纵（水或养分可用性）以评估生态遗产效应和反馈。火灾和放牧研究将解决有关自上而下和自下而上控制生态过程的基本问题，以及异质性对生物多样性和生态系统过程的影响。木本植物入侵，气候变化和慢性氮富集的研究将解决三个最关键的变化发生在世界各地的草原。研究人员也将使用中间火返回处理，询问在中间火间隔下观察到的灌木入侵是否代表一种新的稳定状态。恢复研究将检验关于控制植物多样性和群落组合的基本生态学理论，同时为恢复草原和保护草原生物多样性的更有效战略奠定基础。这项研究是通过一个共同的主题，草原的敏感性和弹性自然和adhergenically改变驱动程序的概念整合。当这些不同的和创造性的研究项目被放在一起，这个长期项目准备解决重大的全球变化现象，并测试有关非线性动力学和交替稳定状态，生产力多样性和干扰稳定性关系，自上而下与自下而上的生态过程，食物网动态和环境异质性的反应调节的基本生态理论。