Soil seed bank responses to anthropogenic disturbances and its vegetation restoration potential in the arid mining area

Close-to-nature restoration of mining areas is becoming widely recognized for its promotion of ecosystem resilience and risk mitigation of biodiversity losses. Soil seed banks can serve as a direct source of natural restoration, as well as a buffer against environmental changes in vulnerable ecosystem. However, in arid mining area, it remains unclear how the anthropogenic disturbances affect the seed banks and what its potential for vegetation restoration. We conducted a field study to investigate the variation of aboveground plant communities and seed banks along the disturbance gradient in an opencast mining area in arid desert of northwestern China. Furthermore, we detected the influence path of disturbance on seed bank density and richness at different layers. The seed bank had considerable density, with persistent seed accounting for 46%. The density had no significant differences along the none-to-moderate disturbance gradient but decreased significantly at the severe level. Meanwhile, the richness had significant differences among all disturbance levels with the highest value at mild level. There were low similarities between soil seed bank and aboveground vegetation, and their species composition was distinctly different. The anthropogenic disturbances reduced soil seed bank directly. Besides, it indirectly decreased the density of persistent seed bank at shallow layer via the negative impact on silt content. In contrast, disturbance indirectly reduced transient seed density and richness mainly via the positive effect on aboveground vegetation. Briefly, mild-to-moderate disturbance had limited negative effects on the soil seed bank and its restoration potential in the arid mining region. Our study highlights the soil seed banks as supplementary indicator to reflect ecological degradation and the significance for ecosystem recovery. The results could be useful in protection and management projects for the restoration of arid mining areas.