Predicting effects of interannual variability in climate and drought on plant community outcomes, resilience, and soil carbon using temporally replicated grassland reconstructions

使用临时复制的草地重建来预测气候和干旱的年际变化对植物群落结果、恢复力和土壤碳的影响

• 批准号: 2343738
• 负责人: Sara Baer
• 金额: $ 78.07万
• 依托单位: University of Kansas Center for Research Inc
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2024
• 资助国家: 美国
• 起止时间: 2024-03-01 至 2029-02-28
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2343738&HistoricalAwards=false
• 关键词: Predicting; effects; interannual; variability; climate

Grasslands provide services that benefit society and there is growing interest in restoring native grasslands to enhance ecosystem services in targeted areas, such as marginal agricultural land. A goal of restoring agricultural land to grassland is to promote the recovery of diverse native plant communities that can withstand and bounce back from periodic stress, and that improve the health of soil degraded from cultivation. However, the composition of plant communities that develop and rate at which soil recovers in restored grasslands is highly variable and difficult to predict. Forecasting plant community outcomes and soil recovery is further complicated by an increasingly variable climate, especially in the southern Great Plains. This research uses a series of grassland restorations established in an agricultural field every other year for twelve years, encompassing a wide range of climate conditions, to understand of the role of climate variability on plant community composition, the resilience of restored communities to drought, and the rate at which carbon accumulates in the soil. This long-term study provides new insights into the role of climate in achieving conservation goals and reduces uncertainty about the capacity for restored grasslands to sequester carbon in soil. The similarly reconstructed grasslands provide a novel framework to test the hypotheses that stochastic variation in climate has deterministic consequences for restored community states, resilience develops as communities age and interact with community state, and climate-driven differences in plant composition contribute to variation in soil carbon accrual. Previously collected and continued measurements of plant species composition are used to model the effect of planting-year climate on restored community trajectories of change. Climate-influenced community states in these grasslands vary uniquely and widely in the ratio of C4-grasses and C3-forbs. The grasses and forbs produce organic matter that varies in both substrate quality and stable carbon isotopic signatures that are measured to determine whether soil carbon accrual is influenced more by recalcitrant or high-quality inputs, respectively. The occurrence of multiple droughts over the course of establishing this long-term experiment provides a rare opportunity to evaluate whether resilience varies predictably with restoration age and whether it interacts with climate-influenced community state. Ultimately, this research helps to transition long-term studies in community ecology toward prediction, advance understanding of factors influencing resilience in ecosystems, and help resolve competing hypotheses regarding plant-based controls on soil carbon accrual.This project is jointly funded by Ecosystem Science and the Established Program to Stimulate Competitive Research (EPSCoR).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.

草原提供造福社会的服务，人们越来越有兴趣恢复原生草原，以增强边际农业用地等目标地区的生态系统服务。将农田恢复为草原的目标是促进多种本土植物群落的恢复，这些植物群落能够承受周期性压力并从中恢复，并改善因耕种而退化的土壤的健康状况。然而，恢复的草原中发育的植物群落的组成和土壤恢复的速度变化很大且难以预测。由于气候日益变化，特别是在大平原南部，预测植物群落结果和土壤恢复变得更加复杂。这项研究使用了十二年中每隔一年在农田中建立的一系列草原恢复，涵盖了广泛的气候条件，以了解气候变化对植物群落组成的作用，恢复的群落对干旱的恢复能力，以及碳在土壤中积累的速率。这项长期研究为气候在实现保护目标中的作用提供了新的见解，并减少了恢复草地固碳能力的不确定性。同样重建的草地提供了一个新的框架来检验以下假设：气候的随机变化对恢复的群落状态具有确定性后果，恢复力随着群落老化并与群落状态相互作用而发展，以及气候驱动的植物组成差异导致土壤碳的变化应计。先前收集和持续测量的植物物种组成用于模拟种植年气候对恢复的群落变化轨迹的影响。这些草原中受气候影响的群落状态在 C4 禾本科植物和 C3 禾本科植物的比例方面存在独特且广泛的差异。禾本科植物和杂草产生的有机物在基质质量和稳定碳同位素特征上都有所不同，通过测量这些有机物可以确定土壤碳累积是否更多地受到顽固或高质量投入的影响。在建立这项长期实验的过程中发生的多次干旱提供了一个难得的机会，可以评估恢复力是否随着恢复年龄的变化而发生可预测的变化，以及它是否与受气候影响的群落状态相互作用。最终，这项研究有助于将群落生态学的长期研究转向预测，促进对影响生态系统恢复力的因素的理解，并帮助解决有关基于植物的土壤碳累积控制的竞争假设。该项目由生态系统科学和该奖项反映了 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。