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.

旱地生态系统覆盖了地球大陆陆地面积的40%以上。他们支持由世界各地的牧场主、农民和牧民组成的当地经济。从以草为主的社区向以灌木为主的社区过渡的频率越来越高，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造成这些变化的各种机制，以预测干旱地区生境的未来。要保持人类福祉所必需的可耕地和生态系统服务，就必须清楚地了解基本机制。该项目吸引了数百名初中和高中学生和教师，他们沿着中格兰德河采样，这是一个高度可见和高度干扰的生态系统。由此产生的数据被当地的保护组织，美国陆军工程兵团，美国垦务局和美国鱼类和野生动物管理局使用，在许多机构中仅举几例，用于管理经济和文化重要地区。博斯克生态系统监测计划的参与者融合了西班牙裔，美洲土著和盎格鲁文化，并整合了来自市中心，郊区和农村地区的参与者。通过将K-12和大学生联系起来进行科学研究，该项目加强了STEM领域的教育。本科培训也很广泛，涉及国家努力招募服务不足的群体进入科学领域以及西南印度理工学院的参与。塞维利亚长期生态研究中心的研究旨在了解非生物驱动因素和限制因素如何影响干旱土地人口，社区和生态系统的脉冲动态和稳定性。该奖项将扩展以前对短期局部尺度过程的研究，以了解脉冲驱动的区域尺度转变和景观单元之间的材料转移。将在草地-灌木过渡区进行一项实验，以了解浅层与深层土壤水分在植物和微生物交换及相关生态系统过程中的作用。降雨操作将施加大季风，以评估降雨脉冲的影响，和脆弱的生物结壳的操作将记录交换和生物相互作用的基础上一个新的循环，真菌整合生态系统功能的转换，转移，和存储C和营养物质。 在松树-杜松林地的新研究将检查植物在这一转变过程中的功能，并评估微生物群落对水处理的反应。这项研究将比较真菌在林地和微生物在草地中所起的作用。对水质和水量的每日和季节变化的高分辨率测量将用于记录火灾等干扰如何与降雨脉冲相互作用，将营养物质和有机物质转移到为格兰德河供水的支流。这些不同活动的结果将被整合，使用模拟模型，记录降水脉冲对植物补充，生长和不同物种的死亡率在植物斑块尺度的影响，以及这些如何驱动长期模式的优势和组成景观。

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

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

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

Quantifying Postfire Aeolian Sediment Transport Using Rare Earth Element Tracers

• DOI: 10.1002/2017jg004284
• 发表时间: 2016-12
• 期刊: Journal of Geophysical Research: Biogeosciences
• 作者: David Dukes;H. B. Gonzales;S. Ravi;D. Grandstaff;R. V. Van Pelt;Junran Li;Guan Wang;J. Sankey

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