Plant community development trends on mixed grass prairie well sites 5 years after reclamation

Abstract

Over the last 90 years, dry mixed grass prairie across North America has been severely impacted by agriculture, urbanization, and oil and gas operations, presenting significant challenges for land reclamation and range management. This study examined how seed mix and natural recovery revegetation treatments influenced plant community development trends on reclaimed well sites in Alberta, Canada. Three seed mixes, dominant wheatgrass (four species with 95% wheatgrass), non-dominant wheatgrass (five species with 80% non-wheatgrass), and diverse (22 grass and forb species), and natural recovery (unseeded) revegetation treatments were compared to undisturbed mixed grass prairie. Five years after reclamation natural recovery led to a plant community with lesser graminoid and greater forb cover, greater species richness and diversity, and greater bare ground relative to seed mix treatments. Seeded treatments resulted in communities dominated by native wheatgrass species. Multivariate tests revealed community composition of undisturbed prairie and the natural recovery treatment differed from seeded treatments. Indicator species analysis showed the natural recovery treatment was dominated by secondary successional perennial species, while the diverse treatment was dominated by native and non-native early to late successional perennial species. This implies that vegetation recovered more rapidly after disturbance with natural recovery than with a diverse seed mix. Non-native species cover showed a declining trend, and five years after reclamation it was <5% across treatments. Natural recovery revegetation was more effective than seeded treatments; however, a diverse seed mix could be used for mixed grass prairie reclamation.