Use of shrub willows (Salix spp.) to develop soil communities during coal mine restoration

Abstract

Afforestation or reforestation in highly degraded environments (e.g., surface mines) is often complicated by the total removal of vegetation and severe soil degradation that occurs during mining operations, necessitating revegetation to be undertaken in tandem with the re-establishment of soil developmental processes. Shrub willows (Salix spp.) are effective as colonizer species initiating revegetation dynamics; however, it is unclear if they also serve as nurse plants facilitating the establishment of soil communities such as those of nematodes. We established a study in a former coal mine site in New Brunswick, Canada, to assess whether the presence of willows on otherwise bare, poorly developed soil contributed to nematode community development and to what degree landform design (e.g., slope) may influence these dynamics. Our results demonstrate that willows can facilitate nematode communities at this site, but that slope strongly influences these effects, likely as a consequence of hydrology and overland water flow. These results confirm the beneficial role that willows can play in reforestation of highly degraded environments both for revegetation and for the re-initiation of soil ecosystem processes.