CAREER: Feedbacks From Drought on the Phytochemical Landscape

该奖项的全部或部分资金来自《2021年美国救援计划法案》(公法117-2)。美国西部正在遭受几个世纪以来最严重的干旱。为了预测干旱将如何影响环境，干旱的影响研究必须包括资源和食物网在空间上的自然变化。植物产生营养和毒素的混合物，这种化学物质因基因和环境的变化而不同。由于植物利用资源在陆地上形成食物网的基础，植物化学可以将资源的变化与食物网的变化联系起来。了解植物化学如何对极端干旱做出反应，有助于理解这些较大系统中的植物。这一职业奖将提高对以下问题的理解：(A)在单个植物和植物群落的尺度上，植物化学如何因应干旱而变化，以及(B)这些变化与植物-动物相互作用和分解的变化的关系。该项目的总部设在内华达州和加利福尼亚州交界处的大盆地沙漠，那里现在极端干旱司空见惯。该奖项将检验极端干旱减少环境变化，从而影响系统功能的假设。该项目包括第一代学生的培训和研究参与，小学生的户外科学体验，以及内华达州社区科学家的研究机会。压力对植物新陈代谢施加严重压力，这可能会降低营养相互作用和土壤碳动态之间的反馈强度，从而简化生态群落。为了验证这一假设，该奖项将支持针对重点植物个体和植物群落的干旱实验。利用西部乳草的室外花园，研究将评估水分的数量和变异性如何影响植物-草食-捕食者的相互作用，以及不同浇水处理的植物组织如何影响分解和土壤呼吸。利用山艾树生态系统中植物群落的干旱避难所和降雨量增加，研究将评估干旱如何在小区尺度上影响植物化学，包括个体化学的变化以及由于群落中不同的生存和补充而产生的变化。然后，这些测量将与节肢动物群落的变化和空间显式设计中土壤碳动态的变化相关。植物化学将使用非定向代谢组学方法进行评估，这些方法考虑化合物的组成和多样性以及它们的浓度。植物-动物相互作用的复杂性也将在马利筋花园中使用草食动物和它们的捕食者的因子组合来测试这种营养反馈的重要性。这项工作将提供对美国西部未来生态系统动态的洞察，以及通过对植物化学的理解我们可以在多大程度上预测这些动态。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).The western United States is suffering from the worst drought in centuries. To predict how drought will affect the environment, the effects of drought studies must include natural variation across space in resources and in food webs. Plants produce mixtures of nutrients and toxins, and this chemistry varies genetically and with changes in the environment. Because plants use resources to form the base of food webs on land, plant chemistry can link variation in resources with variation in food webs. An understanding of how plant chemistry responds to extreme drought could help in understanding plants in these larger systems. This CAREER award will improve understanding of (a) how plant chemistry changes in response to drought at the scales of individual plants and of plant communities, and (b) the relationship of these changes to changes in plant-animal interactions and decomposition. The project is based in the Great Basin Desert on the border between Nevada and California, where extreme drought is now commonplace. The award will test the hypothesis that extreme drought reduces environmental variation, with consequences for system function. The project includes training and research participation of first generation students, outdoor science experience for grade school students, and research opportunities for community scientists in Nevada.Drought imposes acute stress on plant metabolism, which may reduce the strength of feedbacks between trophic interactions and soil carbon dynamics, simplifying ecological communities. To test this hypothesis, the award will support drought experiments on focal plant individuals and on plant communities. Using outdoor gardens of western milkweed, the research will assess how the amount and variability of water impacts plant-herbivore-predator interactions, as well as how plant tissues from different watering treatments influence decomposition and soil respiration. Using drought shelters and rainfall additions in plant communities in sagebrush ecosystems, the research will assess how drought affects plant chemistry at the plot scale, including changes in the chemistry of individuals and changes due to differential survival and recruitment in the community. These measurements will then be related to changes in arthropod communities and in soil carbon dynamics in a spatially explicit design. Plant chemistry will be assessed using untargeted metabolomics approaches that consider the composition and diversity of compounds as well as their concentrations. The complexity of plant-animal interactions will be also manipulated in the milkweed gardens using factorial combinations of herbivores and their predators to test the importance of such trophic feedbacks. The work will provide insight into the dynamics of future ecosystems in the American West and the extent to which we can predict those dynamics through an understanding of plant chemistry.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.