Comparison of Site Preparation and Revegetation Strategies Within a Sphagnum-dominated Peatland Following Removal of an Oil Well Pad

Abstract

Few guidelines exist for the effective revegetation of peatlands following the removal of in-situ oil and gas infrastructure. We conducted a manipulative field study in northeast Alberta, Canada, on a well pad undergoing removal and revegetation to test different management practices for facilitating vegetation establishment and recovery of a sphagnum-dominated peatland. A randomized block design was used to evaluate the effect of various revegetation practices, including augmenting natural recovery with the use of native transplants, acrotelm transfer from a similar intact donor peatland, and the use of variable surface microtopography. Although overall survival of transplants was similar between areas smoothed and left rough, areas that were rough had greater species richness under natural recovery, including trees, shrubs, and other perennial herbs. Moreover, survival and growth of woody transplants (Picea mariana—black spruce and Ledum groenlandicum—Labrador tea) were greater when planted within the top and middle microtopographic positions rather than micro-depressions. Survival of transplanted sedges (Carex spp.) was high at all topographic positions, but benefited the most in growth from planting in depressions. Contrary to expectations, no benefits of acrotelm application were found on vegetation recovery during the first two seasons, and even reduced the presence of some native vegetation. Although transplants directly contributed to revegetation, the recovering peatland remained highly dissimilar (> 90%) in composition relative to the neighboring peatland after two years.