Immediate effects of chemical and mechanical soil preparation techniques on epigaeic arthropod assemblages during reclamation of in situ oil and gas sites in northern Alberta, Canada

Abstract

Epigaeic arthropods have been used worldwide as indicators of post-disturbance recovery in many different types of ecosystems. We used them to evaluate the merit of different reclamation prescriptions applied to areas disturbed by oil and gas exploration and extraction. We compared the short-term effects of different mechanical and chemical site preparation techniques on the epigaeic arthropod fauna of previously reclaimed borrow pits in arrested succession with results from plots in untreated disturbed sites and undisturbed adjacent forest. In general, arthropod diversity increased and abundance decreased with the severity of soil disturbance involved in the silvicultural prescription. We place arthropod communities into four discrete groups reflected in the treatments and the environmental characteristics of the sites: forest species, grassland species, species primarily found in herbicide plots, and species found in disturbed soil. Individual borrow pits accounted for a significant amount of variation in faunal assemblages, suggesting that site location, vagaries of colonization, or disturbance history play a significant role in how the fauna recovers post disturbance. Our study provides baseline data required to document the trajectory of recovery in these sites. Long-term monitoring is essential to evaluate the relative usefulness of reclamation prescriptions in meeting targets established by law.