The effects of different wellpad reclamation practices on plant community recovery
Energy development represents a significant and growing part of the economy in the western United States. In Wyoming, more than 23,000 wells are expected to be drilled in the future. Current reclamation practices require oil and gas disturbances to be reclaimed to a state as close to that of undisturbed land as possible using methods such as soil stockpiling and scraping as well as seeding. In contrast, past reclamation practices required little to no reclamation after wellpads were abandoned. The recovery of plant communities is on abandoned wellpads is important for overall community function, but past studies have found that species richness and cover of some functional groups are slow to recover, whether the site is reclaimed or not. Our study’s main objectives were: 1) to determine if the species composition and abundance in plant communities on abandoned wellpads differs between reclamation eras; 2) to compare species composition and abundance on wellpads to species composition and abundance in undisturbed areas; and 3) to determine if vegetation community recovery on wellpads is limited due to lack of seed availability or factors limiting germination. We sampled aboveground plant communities and the seedbank on 19 sites representing wellpads that were unreclaimed, reclaimed only minimally, or reclaimed to modern standards. Within each site, we compared the wellpad to a nearby, undisturbed area and used an index of recovery to quantify plant community recovery for the whole plant community as well as individual plant functional groups.
Whole plant community recovery differed by reclamation era, with wellpads reclaimed using past practices showing less difference between undisturbed and wellpad subsites than wellpads that were reclaimed using modern practices. Within functional groups, no group showed significant differences between undisturbed and wellpad subsites with past reclamation practices. In contrast, grass and forb cover was significantly greater on undisturbed subsites than wellpads reclaimed with modern methods. This suggests either better recovery or less disturbance on older wellpads, although the extent to which the differences are due simply to a longer recovery time on wellpads reclaimed using older practices is currently unclear. Further analysis will better explain the specific effects of reclamation era on different functional types and species composition on wellpads. This, in turn, will help to inform future reclamation practices as well as maximize the chances of plant community recovery after oil and gas disturbance.