LTER V: Long Term Pulse Dynamics in an Aridland Ecosystem

LTER V：旱地生态系统中的长期脉冲动力学

• 批准号: 1440478
• 负责人: William Pockman
• 金额: $ 197万
• 依托单位: University of New Mexico
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2015
• 资助国家: 美国
• 起止时间: 2015-04-01 至 2019-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=1440478&HistoricalAwards=false
• 关键词: LTER; Long; Term; Pulse; Dynamics

Arid-land ecosystems cover more than 40% of continental land area of the Earth. They support local economies comprised of ranchers, farmers, and pastoralists around the world. Transitions from grass- to shrub-dominated communities are increasing in frequency, threatening human well-being and these economies in both developed and developing countries. This long-term project explores the diverse mechanisms responsible for these changes in an effort to predict the future of arid-land habitats. Clear understanding of underlying mechanisms is necessary to maintain arable land and ecosystem services necessary for human well being. The project engages hundreds of middle and high school students and teachers who sample along the Middle Rio Grande, a highly visible and highly disturbed ecosystem. The resulting data are used by local conservancy groups, the US Army Corps of Engineers, the US Bureau of Reclamation, and the US Fish and Wildlife Service, to name a few among many agencies, in management of an economically and culturally important region. Participants in the Bosque Ecosystem Monitoring Program blend Hispanic, Native American, and Anglo cultures and integrate participants from inner-city, suburban, and rural areas. By connecting K-12 and university students in scientific research, the project enhances education in STEM fields. Undergraduate training is also extensive, involving national efforts to recruit under-served groups into science and participation from the Southwest Indian Polytechnic Institute. Research at the Sevilleta Long Term Ecological Research site seeks to understand how abiotic drivers and constraints affect the pulse dynamics and stability of arid-land populations, communities, and ecosystems. This award will extend previous research on short-term, local-scale processes to understand pulse-driven regional-scale transitions and transfer of materials between landscape units. An experiment at the grassland-shrubland transition will be initiated to understand the roles of shallow versus deep soil moisture in plant and microbial exchanges and associated ecosystem processes. A rain manipulation will impose large monsoons to assess the impact of rainfall pulses, and manipulations of fragile bio-crusts will document exchanges and biotic interactions underlying a novel loop by which fungi integrate ecosystem functions by transforming, translocating, and storing C and nutrients. New research in pinon-juniper woodlands will examine plant function across this transition and assess microbial community responses to water manipulations. This research will compare the role that fungi play in woodlands with the roles that microbes play in grasslands. High resolution measurements of daily and seasonal changes in water quality and quantity will be used to document how disturbances such as fire interact with pulses of rain to transfer nutrients and organic matter into tributaries that feed the Rio Grande River. Results from these diverse activities will be integrated, using simulation models, to document the effects that precipitation pulses have on plant recruitment, growth, and mortality of different species at the plant to patch scale, and how these drive long-term patterns in dominance and composition across landscapes.

干旱的生态系统覆盖了地球大陆土地面积的40％以上。他们支持由世界各地牧场主，农民和牧民组成的地方经济。从基层到灌木主导的社区的过渡频率正在增加，威胁到发达国家和发展中国家的人类福祉和这些经济体。这个长期项目探讨了负责这些变化的各种机制，以预测干旱地栖息地的未来。对基本机制的清晰了解对于维持人类福祉所需的可耕地和生态系统服务是必要的。该项目与数百名中学生和老师与他们沿着里奥格兰德（Rio Grande）进行了采样，这是一个非常明显且受到高度干扰的生态系统。所得的数据由当地保护组织，美国陆军工程兵团，美国开垦局和美国鱼类和野生动物服务局使用，在许多机构中仅举几例在经济和文化上重要的地区。 Bosque生态系统监测计划的参与者融合了西班牙裔，美洲原住民和盎格鲁文化，并整合来自城市，郊区和农村地区的参与者。通过将K-12和大学生连接到科学研究中，该项目可以增强STEM领域的教育。本科培训也是广泛的，涉及全国努力，以招募服务不足的群体进入科学和西南印度理工学院的参与。 Sevilleta长期生态研究网站的研究旨在了解非生物驱动因素和约束如何影响干旱地种群，社区和生态系统的脉搏动态和稳定性。该奖项将扩大有关短期，地方规模过程的研究，以了解脉搏驱动的区域尺度过渡和景观单元之间材料的转移。将开始在草原公共转变的实验，以了解植物和微生物交换和相关生态系统过程中浅层土壤水分的作用。降雨操纵将施加大型季风来评估降雨脉冲的影响，对脆弱的生物壳的操纵将记录一种新型环路的交换和生物相互作用，通过这种循环，真菌通过转化，易位，易位和储存C和营养物质来整合生态系统功能。 Pinon-Juniper Woodlands的新研究将检查该过渡过程中的植物功能，并评估微生物社区对水操作的反应。这项研究将将真菌在林地中扮演的角色与微生物在草原中扮演的角色进行比较。每天的高分辨率测量和水质和数量的季节变化将用于记录诸如火灾之类的干扰如何与雨水相互作用，以将养分和有机物转移到养活里奥格兰德河的支流中。这些不同活动的结果将使用仿真模型进行整合，以记录降水脉冲对植物植物的植物募集，生长和死亡率的影响，以弥补斑块量表，以及这些如何驱动跨景观中的优势和组成的长期模式。

项目成果

Drought consistently alters the composition of soil fungal and bacterial communities in grasslands from two continents

• DOI: 10.1111/gcb.14113
• 发表时间: 2018-07
• 期刊: Global Change Biology
• 影响因子: 11.6
• 作者: R. Ochoa‐Hueso;S. Collins;M. Delgado‐Baquerizo;K. Hamonts;W. Pockman;R. Sinsabaugh;Melinda D. Smith

The competitive advantage of a constitutive CAM species over a C 4 grass species under drought and CO 2 enrichment

干旱和 CO 2 富集条件下组成型 CAM 物种相对于 C 4 禾本科物种的竞争优势

• DOI: 10.1002/ecs2.2721
• 发表时间: 2019
• 期刊: Ecosphere
• 影响因子: 2.7
• 作者: Yu, Kailiang;D'Odorico, Paolo;Collins, Scott L.;Carr, David;Porporato, Amilcare;Anderegg, William R. L.;Gilhooly, III, William P.;Wang, Lixin;Bhattachan, Abinash;Bartlett, Mark
• 通讯作者: Bartlett, Mark

Ecological engineers’ nests benefit plant recovery following fire in a semiarid grassland, New Mexico, USA

美国新墨西哥州半干旱草原火灾后，生态工程师的巢穴有利于植物恢复

• DOI: 10.1111/jvs.12755
• 发表时间: 2019
• 期刊: Journal of Vegetation Science
• 影响因子: 2.8
• 作者: Nicolai, Nancy;Overbeck, Gerhard
• 通讯作者: Overbeck, Gerhard

Chlorophyll Fluorescence Better Captures Seasonal and Interannual Gross Primary Productivity Dynamics Across Dryland Ecosystems of Southwestern North America

• DOI: 10.1002/2017gl075922
• 发表时间: 2018-01
• 期刊: Geophysical Research Letters
• 影响因子: 5.2
• 作者: W. Smith;J. Biederman;R. Scott;David J. P. Moore;M. He;J. Kimball;Dong Yan;A. Hudson;M. Barnes;N. MacBean;A. Fox;M. Litvak

From structure to function: Understanding shrub encroachment in drylands using hydrological and sediment connectivity

• DOI: 10.1016/j.ecolind.2018.11.039
• 发表时间: 2019-03
• 期刊: Ecological Indicators
• 影响因子: 6.9
• 作者: L. Turnbull;J. Wainwright