LTREB Renewal: Long-term ecosystem responses to directional changes in precipitation amount and variability in an arid grassland

LTREB 更新：干旱草原中降水量和变异性方向变化的长期生态系统响应

• 批准号: 2326482
• 负责人: Osvaldo Sala
• 金额: $ 67万
• 依托单位: Arizona State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2028-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2326482&HistoricalAwards=false
• 关键词: LTREB; Renewal; Long; term; ecosystem

Rainfall plays an important role in dryland environments. Climate is changing fast and significantly. A drier and more variable climate is expected, which could affect dryland environments. Predicting the effects of a new climate on the functioning of ecosystems is the most pressing objective of ecology. Understanding, the way ecosystems will function under these novel conditions is necessary to develop management strategies that generate optimal societal outcomes. Drylands are very important because they cover 40% of the terrestrial surface and provide invaluable goods and services. These goods and services range from forage production to recreation. This project will continue two unique long-term experiments, where researchers separately manipulated rain amount and variability in a desert grassland in New Mexico for 16 years. Results from the first 5 years of this project yielded unexpected results. Drought had indirect effects on the composition of plant species that offset the direct effects of drought. The continuation of the project will determine how these different responses occurred. Broader impacts include directly contributing to increasing participation of underrepresented groups. This project will collaborate with Asombro Institute for Science Education by building a new demonstration project at the 960-acre Chihuahuan Desert Nature Park. Asombro is a non-profit organization that provides award-winning science education to more than 22,000 children and 4,500 adults annually in southern New Mexico and western Texas.This proposal is guided by two hypotheses about dryland responses to changes in amount and variability of precipitation. (1) Endogenous Mechanisms: Biogeochemical and demographic phenomena mediate abrupt or continuous changes in populations, communities and ecosystem processes. (2) Exogenous Phenomena: El Niño events at 3-4-year periods interact with changes in low-frequency Pacific Decadal Oscillation (PDO) and Atlantic Multi-Decadal Oscillation (AMO). These climate events interact with internal mechanisms. Jointly, they affect system resistance, and lead to changes in species composition and ecosystem processes. After 16 years, the ecosystem seems to be at crossroads regarding soil organic nitrogen forms. This condition may result in a new N-water limitation. The project will continue two unique long-term precipitation-manipulation experiments that separately manipulated precipitation amount and variability in a desert grassland in New Mexico for 16 years. The long-term manipulations of precipitation amount are accomplished using rainout shelters coupled with irrigation systems. This project will directly contribute to increasing participation of underrepresented minorities with emphasis on Hispanic students. This project will collaborate with Asombro Institute for Science Education by building a new demonstration project at the 960-acre Chihuahuan Desert Nature Park. Asombro is a non-profit organization that provides award-winning science education to more than 22,000 children and 4,500 adults annually in southern New Mexico and western Texas.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.

降雨在旱地环境中发挥着重要作用，预计气候将变得更加干燥和多变，这可能会影响旱地环境，这是生态学最紧迫的目标。了解生态系统在这些新条件下的运作方式对于制定产生最佳社会成果的管理策略非常重要，因为它们覆盖了 40% 的陆地表面并提供了宝贵的商品和服务。该项目将继续进行两项独特的长期实验，研究人员在新墨西哥州的沙漠草原上分别控制了 16 年的降雨量和变化，该项目的前 5 年的结果产生了意想不到的结果。对植物物种组成的间接影响抵消了干旱的直接影响 该项目的继续将决定这些不同的反应如何发生，包括直接促进代表性不足的群体的参与。教育在占地 960 英亩的奇瓦瓦沙漠自然公园建立一个新的示范项目 Asombro 是一个非营利组织，每年为新墨西哥州南部和德克萨斯州西部的 22,000 多名儿童和 4,500 名成人提供屡获殊荣的科学教育。以关于旱地对降水量和变率变化的响应的两个假设为指导（1）内生机制：生物地球化学和人口现象介导人口、群落和生态系统过程的突然或持续变化。 （2）外生现象：3-4年周期的厄尔尼诺事件与低频太平洋年代际振荡（PDO）和大西洋多年代际振荡（AMO）的变化相互作用，这些气候事件与内部机制共同相互作用。影响系统抵抗力，并导致物种组成和生态系统过程的变化。16年后，生态系统似乎处于土壤有机氮形式的十字路口，这种情况可能会导致新的氮水限制。将继续进行两项独特的长期降水操纵实验，分别在新墨西哥州的沙漠草原上进行 16 年的降水量和变化。该项目将直接使用防雨棚和灌溉系统来完成降水量的长期操纵。该项目将与 Asombro 科学教育研究所合作，在占地 960 英亩的非盈利性奇瓦瓦沙漠自然公园建设一个新的示范项目。该组织每年为新墨西哥州南部和德克萨斯州西部超过 22,000 名儿童和 4,500 名成年人提供屡获殊荣的科学教育。该奖项反映了 NSF 的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。