Abstract
Disturbance on certified reclaimed wellpads has been shown to shift native grassland sites into an alternative successional state where native plant communities are unable to recover to reference conditions over time. The objective of this project is to find out if these disturbances specifically impact the community recovery of native graminoid, forb, and lichen communities in Alberta’s Southern Grasslands and what role invasive species play in their recovery trajectories, to provide recommendations for how future reclamation practices can better account for these relationships when planning for recovery. Analysis focused on grasslands data taken from 18 paired wellpad and reference sites in Southern Alberta, including a lichen community survey, and percent cover of vascular plants and soil data collected using a nested quadrats sampling design. R 4.5.2 GUI 1.82 High Sierra build (8556) was used to complete a Cluster Analysis (general recovery trajectories), PCoA (lichen recovery), NMDS (vascular plant recovery), alongside perMANOVA, and other univariate methods to test for statistical significance between groups. In conclusion, the study found that the sample location (wellpad or reference) seems to have a bigger influence on recovery than age class, though it seems that it takes a longer amount of time (at least 30 or more years) for lichens, graminoids, and forbs to recover to reference conditions on wellpad sites. Additionally, reclamation practices seem to better support vascular plant recovery compared to lichens. Disturbance seems to be increasing diversity and heterogeneity on wellpad sites to some degree, and Crested Wheatgrass in particular seems to be taking advantage of disturbance to establish itself strongly on wellpad locations, though it may have a bigger influence on whether vascular plants can recover to reference conditions than lichens. Reclamation practitioners and new reclamation policies should focus on implementing regular monitoring and management to ensure that invasive species such as Crested Wheatgrass do not outcompete native plants during the years it takes for these sites to return to reference conditions. Native grasses and forbs that are strong competitors should be considered for restoration, and site-specific conditions should be taken into account when deciding which species to plant, especially to encourage the return of important native lichen species that may only be able to tolerate a narrow set of environmental conditions.