Plant community assembly outcomes can be contingent upon establishment year (year effects) due to variations in the environment. Stochastic events such as interannual variability in climate, particularly in the first year of community assembly, contribute to unpredictable community outcomes over the short term, but less is known about whether year effects produce transient or persistent states on a decadal timescale. To test for short‐term (5‐year) and persistent (decadal) effects of establishment year climate on community assembly outcomes, we restored prairie in an agricultural field using the same methods in four different years (2010, 2012, 2014, and 2016) that captured a wide range of initial (planting) year climate conditions. Species composition was measured for 5 years in all four restored prairies and for 9 and 11 years in the two oldest restored prairies established under average precipitation and extreme drought conditions. The composition of the four assembled communities showed large and significant differences in the first year of restoration, followed by dynamic change over time along a similar trajectory due to a temporary flush of annual volunteer species. Sown perennial species eventually came to dominate all communities, but communities remained distinct from each other in year five. Precipitation in June and July of the establishment year explained short‐term coarse community metrics (i.e., species richness and grass/forb cover), with wet establishment years resulting in a higher cover of grasses and dry establishment years resulting in a higher cover of forbs in restored communities. Short‐term differences in community composition, species richness, and grass/forb cover in restorations established under average precipitation and drought conditions persisted for 9–11 years, with low interannual variability in the composition of each prairie over the long term, indicating persistently different states on a decadal timescale. Thus, year effects resulting from stochastic variation in climate can have decadal effects on community assembly outcomes.

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Since the passage of legislation in 1977, Appalachian mineland reclamation is typically completed using non-native C₃ grasses and forbs. Alternatively, reclamation with native prairie (C₄) grasses and forbs offers a more ecologically friendly alternative that can contribute to native plant conservation and potentially improve soil properties more quickly than shallower rooted C₃ cool-season grasses. We assessed the establishment of native prairie after reclamation, evaluating three treatments for six years after planting—traditional cool season planting, native prairie planted at light density, and native prairie planted at heavy density. All treatments reached the objectives of reclamation—percentage of ground covered by vegetation—within 2 years after planting. All treatments at all sites, except for one site by treatment combination near a forest, showed an increase in plant species richness and Shannon–Wiener diversity in the first four years of reclamation, a peak around 5 years, and subsequent decrease. Little difference in plant richness and Shannon–Wiener diversity among treatments was observed. However, the two native seed mixes quickly diverged from the traditional mix in terms of community structure and diverged further over time, with both native treatments heading towards a more desirable native prairie grassland state, while the traditional mix remained dominated by non-native cool season grasses. The native treatments also exhibited greater increase in microbial biomass and fungi:bacteria ratio over time compared to the traditional mix. Soil organic carbon increased over time regardless of seed mix treatment. Exchangeable base cations and phosphorus generally decreased over time, as expected, regardless of seed mix treatment, likely due to uptake from established plants. Native grassland species were able to establish despite inclusion of some traditional species in the native mix. Native plant establishment likely resulted in benefits including pollinator resources, bird and wildlife habitat, and increased soil health, and we recommend that native prairie mixes be used directly in reclamation moving forward, as they are able to meet reclamation goals while establishing a successful native prairie plant community.

Introduction: Conventional reclamation methods to recover dryland ecosystems after mineral extraction often have low success. Alternative reclamation techniques may help overcome the many challenges to establishing persistent native vegetation and stable soils. Objectives: Compare conventional reclamation approaches that focus primarily on soil stabilization to alternative approaches that may improve native ecosystem restoration at the Kanab North Mine in northern Arizona. Methods: In a fully crossed experiment, conventional seed mix (native and non‐native species) and seeding methods (drill‐seeding) were compared to alternative practices, including a native‐only seed mix, connectivity modifiers (ConMods) with hand seeding, and a biocrust inoculation. Restoration metrics like plant establishment, species composition, soil surface cover and stability, biocrust establishment, and near‐surface wind‐driven sediment were monitored over the first 5 years post‐reclamation. Results: While all restoration metrics improved with time, compared to traditional methods, ConMods increased total, graminoid, and native plant species cover, and the native‐only seed mix increased woody, native, and perennial species cover. Biocrust inoculation increased late‐successional biocrust development, but biocrusts only persisted over 5 years in combination with ConMods. Soil stability increased in all treatments, but both ConMods and biocrust inoculation increased stability compared to traditional practices. Conclusion: Overall, alternative approaches to reclamation tested here (ConMods, native seed, and biocrust inoculation) were more effective than traditional practices at increasing total plant cover, facilitating biocrust establishment, and promoting soil stability after uranium mine reclamation.