COLLABORATIVE RESEARCH: LTREB RENEWAL: The role of ecological heterogeneity in a long-term grassland restoration experiment

通过生态恢复重建生态系统提供了一个测试当前对环境条件如何影响生物多样性的理解的机会。恢复成功的一个标准是重建的群落是否能够承受自然发生的周期性压力，然而，确定对促进重建生态系统的生物多样性和恢复力最重要的环境因素需要数十年的研究。与长期耕作后保持不变和均质化的土壤条件相比，该研究将扩展草原植物多样性和生产力对土壤养分和深度的响应的重建记录，这些土壤养分和深度被改变以创造更多物种共存的可变条件。这项为期25年的田间试验将测试土壤环境的变化是否会影响植物多样性以及重建生态系统对气候变化和干旱的适应能力。这些信息将用于制定建议，以大规模重建多样化和有弹性的草原，为野生动物提供食物和栖息地。该项目还将为本科生和研究生提供培训，并为自然资源管理者、高中教师和公众提供有关草原恢复的教育。试验设计包括重复的地块，分配给四种异质性处理，包括不操作、三种土壤养分水平、两种土壤深度水平或六种土壤养分和深度组合。研究地点位于降水量年际变化较大的康扎草原长期生态研究点。先前的研究表明，在恢复的前15年里，所有处理方法的植物多样性都急剧下降，只有在增加新物种和在更大程度上增加异质土壤时才会抵消。这促使新物种在接下来的五年里不断增加。植物组成、生产力和资源，如光和土壤养分，将在相同的永久采样区使用相同的方法进行额外五年的测量，捕捉四分之一个世纪的生态系统发展和2012年和2018年发生的干旱。这些数据将用于测试土壤资源的空间异质性是否能长期维持更多样化和可变的植物群落，以及这种生态异质性是否会使草原对干旱的恢复能力更难以预测。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。

Reconstructing ecosystems through ecological restoration presents an opportunity to test current understanding of how environmental conditions affect biodiversity. One criterion for restoration success is whether reconstructed communities can endure naturally-occurring periodic stress, however, identifying the environmental factors most important for promoting biodiversity and resilience in reconstructed ecosystems requires decades of study. This research will extend a record of reconstructed prairie plant diversity and productivity in response to soil nutrients and depth that were altered to create variable conditions for more species to coexist, compared to soil conditions left unchanged and homogenized, following long-term tillage. The 25-year field experiment will test whether variation in the soil environment affects plant diversity and resilience of reconstructed ecosystems to climate variability and drought. This information will be used to develop recommendations for large-scale efforts to reconstruct diverse and resilient grasslands that provision food and habitat for wildlife. This project will also provide training of undergraduate and graduate students, as well as foster education about prairie restoration for natural resource managers, high school teachers, and the general public.The experimental design contains replicated plots assigned to four heterogeneity treatments that contain either no manipulations, three soil nutrient levels, two soil depth levels, or six combinations of soil nutrients and depth. The study site is located at the Konza Prairie Long Term Ecological Research Site, which has high interannual variation in precipitation. Prior research revealed a precipitous decline in plant diversity across all treatments over the first 15 years of restoration, offset only when new species were added and, to a greater extent, more heterogeneous soil. This motivated continuous addition of new species for an additional five years. Plant composition, productivity, and resources, such as light and soil nutrients, will be measured in the same permanent sampling areas using the same methods for an additional five years, capturing ecosystem development for one quarter of a century and droughts occurring in 2012 and 2018. These data will be used to test whether spatial heterogeneity in soil resources sustains more diverse and variable plant communities over the long term and whether this ecological heterogeneity makes grassland resilience to drought less predictable.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.