Persistent agricultural legacy in soil influences plant restoration success in a Great basin salt desert ecosystem.
Agricultural legacies in arid and semi-arid environments can hinder revegetation efforts designed to mitigate erosion, slow the spread of invasive weeds, and improve ecosystem services. Restoration outcomes may be improved by understanding how altered soil properties impact the establishment of desired plant species. In this study, we characterized soil differences between a former agricultural field, restored by seeding shrubs and grasses, and a relatively undisturbed native ecosystem dominated by the same species of shrubs. We then asked which soil characteristics were associated with high and low densities of seeded shrubs, seeded grasses, and weeds in the agricultural field. Finally, we identified shrub density-soil relationships in the native sites and asked how they differed from associations in the restored field. Many soil properties were significantly different between plots in the agricultural field and the native sites in ways consistent with decades of agricultural use. Soil characteristics predicted the density of three out of four species of shrub seedlings, seeded annual grasses, and weeds in the agricultural field, and explained up to half the variance in plant density. By contrast, soil characteristics were associated with > 50% of the variance in mature shrub density in native shrub ecosystems, and soil characteristics associated with plant density in native sites were different than those associated with seedling density in the agricultural field. Our results demonstrate that seedling emergence in former agricultural fields can be predicted by knowledge of easily measured surface soil characteristics, even for deeply rooted shrub species common in arid ecosystems.