Rapid Recovery of Plant–pollinator Interactions on a Chronosequence of Grassland-Reclaimed Mines

Reclamation of abandoned mines to grassland may benefit non-target wildlife like pollinators by providing conservation habitat. Co-colonization of wildflowers and pollinators has been used to measure ecological recovery in other disturbed herbaceous habitats. Revegetated surface coal mines in eastern North America are a unique system in which to study re-establishment of plant–pollinator interactions because they are field islands isolated by forest. Using a time series of 10 grassland-reclaimed mines (aged < 10, 10–20, or > 20 years) in Ohio, USA, we evaluate whether former mines provide habitat for bees, seek insights into species accumulation as sites mature, and examine the consequences for bee conservation and plant–pollinator interactions. In 120 h of netting over two consecutive years, we documented 7749 bees of 139 species visiting 117 wildflower species. Bee richness did not differ between young and mature sites, suggesting that diverse communities established rapidly following reclamation and persisted. Bee species assemblage, however, differed between sites < 10 versus > 10 years post-reclamation, and was influenced by vegetation and the amount of nearby forest. Plant–bee networks on sites > 10 years old had more links per species and greater network nestedness than new reclamations, suggesting the development of a core community of interacting species that stabilize pollination services over time. Reclamation grasslands are not typically considered high-quality pollinator conservation habitat, but we found that they harbor a diverse bee fauna similar to other regional meadow habitats. Reclaimed mines remain undeveloped for many years, and can accumulate pollinator species and export bees to the surrounding landscape.