Recovery of dry mixed grass prairie well sites 15 years after reclamation

Abstract

In the mixed grass prairie region of North America, well sites and their associated infrastructure have many ecological effects, including changes to soil physical, chemical and biological properties, loss of vegetation cover, altered plant species composition and habitat fragmentation. Reclamation of disturbed grassland is a challenge faced by many rangeland and conservation managers. The objective of this research was to examine the effect of time on reclaimed grassland well site soil properties and plant communities in southern Alberta. Seeding with three mixes of different numbers of species and proportions of native wheatgrasses (Triticeae tribe) was compared to natural recovery and undisturbed prairie after 15 years. Chernozemic soil was more similar to undisturbed prairie than Solonetzic soil, where soil chemical properties and plant species composition were less resilient following disturbance in some revegetation treatments. All reclaimed treatments had significantly lower soil organic matter, organic carbon and total nitrogen than undisturbed prairie. Vegetation cover and species richness in reclaimed sites did not usually differ from undisturbed prairie. An increase in the proportion of native wheatgrass cultivars in a seed mix did not result in a community dominated by them. Multivariate analysis showed species compositional differences in seeded and natural recovery relative to undisturbed prairie on Solonetzic soil, with no difference on Chernozemic soil except with the dominant wheatgrass seed mix. Thus recovery may require longer than 15 years for Solonetzic soil and revegetation with a dominant wheatgrass seed mix. Presence of early to late successional species indicated natural recovery could be a potential option for mixed grass prairie well site reclamation.