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

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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.