Quantifying the microbial contribution to community recovery from drought

了解生态群落如何从极端天气事件中恢复，可以提高我们管理和提高其生产力和服务的能力。预计极端干旱将在许多地区增加，并且在干旱和半干旱旱地可能至关重要，这些地区往往比湿润的生态系统对干旱更敏感。该项目利用以前nsf资助的基础设施，在干旱草原上进行实验性干旱，以确定土壤微生物在多大程度上有助于从极端干旱中恢复过来。先前的研究发现了两个关键的结果，但在当代研究中尚未统一。首先，干旱通过改变微生物的组成在土壤中留下了遗产；干旱结束后，这一遗产会持续很长时间。其次，微生物的添加可以加速群落在受到干扰后的恢复。综上所述，这两个结果表明，土壤微生物可以推动干旱后生态恢复的步伐，但还需要实验研究。该项目将在田间和温室中进行微生物实验，以确定干旱对旱地的影响程度，并阐明土壤微生物对恢复和恢复能力的重要性。该项目通过支持一名西班牙裔女性博士后研究员、两名女性研究生（一名西班牙裔）和本科生的独立研究经历（包括与西南印度理工学院的合作）来培养下一代多元化的科学家。在一所服务于西班牙裔的机构中，一个新的探究性实验模块为生物学专业学生提供了服务，一个以干旱为重点的K-12单元提高了下一代科学标准。该项目具有全球重要性，因为旱地占陆地面积的比例很大（~45%），并且迅速扩大，对全球碳波动有很大影响。近40%的人生活在世界旱地，提高对旱地从干旱中恢复的过程的了解，可以通过微生物修正实现快速恢复，从而提供新的土地管理战略。该项目解决了生态问题：微生物如何促进干旱后植物群落和生态系统功能的恢复？虽然之前的研究已经记录了气候破坏的遗留影响，但这项拟议的工作将是第一次使用微生物实验来量化微生物对恢复过程的贡献。本项目利用地表微生物（生物土壤结皮）和土壤微生物，评价其对实验性干旱后生态恢复的影响。一项微生物互惠移植实验将测试干旱前微生物的恢复如何加速相对于干旱遗留微生物的恢复。真菌环实验将评估连接表面生物结皮与植物根系的真菌网络是否比这些网络被破坏时促进更快的恢复。最后，温室植物-土壤反馈实验将确定干旱是否会加强（或减弱）影响植物生产力恢复力的反馈。该项目通过包括植物生活史、生长形式和资源需求的变化，以及微生物组成和土壤环境的变化，推广到全世界的干旱草原。研究活动整合了进化过程（干旱改变优势生产者的基因型频率）、群落动态（植物和微生物组合）和生态系统过程（土壤碳和养分），以阐明微生物有助于从极端天气事件中恢复的途径。该奖项反映了美国国家科学基金会的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。

Understanding how ecological communities recover from extreme weather events can improve our ability to manage and enhance their productivity and services. Extreme droughts are predicted to increase in many regions, and may be critically important in arid and semi-arid drylands, which are often more sensitive to drought than wetter ecosystems. This project leverages previously NSF-funded infrastructure for creating experimental drought in dry grasslands in order to determine how much soil microbes aid in the recovery from extreme drought. Prior research has uncovered two key results that have yet to be united in contemporary research. First, drought leaves a legacy in the soil by changing the composition of microbes; this legacy can persist long after drought has ended. Second, additions of microbes can speed community recovery after disturbance. Combined, these two results suggest that soil microbes could drive the pace of ecological recovery from drought, but experimental studies are needed. This project will use microbial experiments in the field and greenhouse to determine the magnitude of drought impacts on drylands and elucidate how much soil microbes matter to recovery and resilience. This project trains the next-generation of diverse scientists by supporting a female Hispanic postdoctoral researcher, two female graduate students (one Hispanic), and independent research experiences for undergraduates, including partnership with the Southwestern Indian Polytechnic Institute. A new inquiry-based laboratory module reaches biology majors at a Hispanic-serving institution, and a drought-focused K-12 unit enhances next-generation science standards. The project has global importance because drylands occupy a large (~45%) and rapidly expanding percentage of land area and contribute greatly to global carbon fluctuations. Nearly 40% of people live in the world's drylands, and improved understanding of the processes by which drylands recover from drought may enable rapid restoration via microbial amendments, delivering new land management strategies. This project addresses the ecological question: How do microbes promote the recovery of plant communities and ecosystem functions following drought? While prior studies have documented the legacy effects of climate disruptions, the proposed work would be among the first to use microbial experiments to quantify how much microbes contribute to the recovery process. This project manipulates surface microbes (biological soil crusts) and soil microbes to evaluate their influences on ecological recovery from experimental drought. A microbial reciprocal transplant experiment will test how restoration of pre-drought microbes speeds recovery relative to microbes with a drought legacy. A fungal loop experiment will evaluate whether fungal networks that link surface biocrusts with plant roots promote faster recovery than if these networks are disrupted. Finally, a greenhouse plant-soil feedback experiment will determine whether drought intensifies (or weakens) feedbacks that affect the resilience of plant productivity. The project generalizes to dry grasslands worldwide by including variation in plant life history, growth form and resource requirements, as well as variable microbial compositions and edaphic contexts. Research activities integrate evolutionary processes (drought alters genotype frequencies in dominant producers), community dynamics (of both plant and microbe assemblages), and ecosystem processes (soil carbon and nutrients) to elucidate the pathways through which microbes contribute to recovery from extreme weather events.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.