Invasive autumn olive performance varies in different reclamation conditions: implications for restoration.
Surface mining has caused significant disturbance globally, and is responsible for the loss of more than 600,000 ha of the world's largest temperate deciduous forest in the Appalachian region of the United States alone. Due to the heavy disturbance on mine lands, invasive plants have become dominant on many former coalfields, some of which were intentionally planted with exotic species. The establishment of invasive plants on these disturbed lands has often led to reductions in establishment of desirable native species. Autumn olive (Elaeagnus umbellata), an exotic nitrogen-fixing shrub, is a problematic invasive species on reclaimed sites in Appalachia. To better understand how reclamation conditions affect autumn olive, we assessed the effects of the mine-soil substrate and vegetation seeding on autumn olive establishment and growth. In each experiment, we also manipulated the herbaceous plant community to further examine effects on autumn olive establishment and growth. In spring 2015, we transplanted 480 1-year-old autumn olive seedlings across both experiments. After 2 years of growth, autumn olive performed better in weathered-rock than in unweathered-rock substrates; in bare-ground plots than in vegetated plots; and in tree-compatible (low-competition) seeding than in more-competitive conventional seeding. No treatment precluded autumn olive establishment. However, our results show that strategic use of beginning substrates and planting mixes can have strong inhibitory effects on invasive plants, but also that substrate and herbaceous-plant community conditions favorable to establishment of native trees are also favorable to autumn olive.