Reclamation is not the primary determinant of soil recovery from oil and gas development in Wyoming sagebrush systems

Abstract

Dryland soils store approximately 10-15% of the worlds soil organic matter (SOM) to 1 m. Threats to carbon stocks in global dryland soils include cultivation, overgrazing, urbanization, and energy development. To limit loss of carbon from these soils, it is important to understand, first, how disturbances affect SOM and second, how SOM recovers after disturbance. In this study, we address current gaps in our understanding of the effects of oil and gas development and reclamation on SOM in the sagebrush steppe of Wyoming, a cold temperate shrub-dominated dryland. Most studies have found that soil disturbance, including from the respreading of topsoil during wellpad reclamation, is damaging to SOM stores; however, research on ~80 year old unreclaimed oil and gas wellpads found no difference in SOM between wellpads and undisturbed sites. Using a chronosequence approach and paired study design, we evaluated the effects of reclamation on SOM by comparing undisturbed sites to wellpads where reclamation activities either had or had not occurred. Our results suggest that the most important factor in recovery of SOM after disturbance in this area was not the presence or absence of reclamation, but time since wellpad abandonment and spatial heterogeneity of plants. Further study on the effectiveness of different reclamation techniques is warranted if the goal of reclamation is to aid SOM recovery and prevent further C loss from these systems.