Recent advances in horizontal drilling and hydraulic fracturing (since 2000) have greatly increased oil and gas development in the West. In a new General Technical Report (RMRS-GTR-384) titled Biological Assessment of Oil and Gas Development on the Little Missouri National Grassland, scientists describe the actual and potential effects of oil and gas development on the largest designated National Grassland in the United States located in western North Dakota. Written by Rocky Mountain Research Station Ecologists Jack Butler (emeritus scientist), Jacqueline Ott and collaborators, the GTR focuses on the effects of oil and gas development on soils, vegetation, and wildlife.
Grassland managers across the Great Plains will find this an especially useful resource because it provides information specific to grassland systems, particularly grasslands in the northern Great Plains. According to Ott, “Our goal was to provide an overview and summary that provides a broad background useful to all grassland managers as a reference and starting place to help identify and address potential outcomes. Finding opportunities to mitigate oil and gas development effects requires a solid understanding of the potential impacts.”
Three threatened species or species of concern—the Dakota Skipper (a butterfly), Sprague’s Pipit (a songbird), and the Northern Long-Eared Bat—are covered extensively in the report.
One highly relevant aspect of the report for grassland managers is the synthesis of current literature describing the known direct outcomes of oil and gas development for the biological resources of the area and to other grasslands. For example, the construction of oil well pads, roads, and pipelines removes the surface vegetation and mixes upper soil layers. Restoration efforts are often required on two separate occasions: (1) early on, when the site is complete, and the construction footprint is reduced to its operating footprint, and (2) at the end of the project when infrastructure is completely removed at the completion of oil extraction. The report points out that well-site reclamation almost always benefits from using organic amendments, which have a very positive effect on soil biological activity. However, a potential tradeoff is that the use of these amendments may introduce invasive plants to the area.
Oil and gas development also affects wildlife, mainly through habitat loss and fragmentation, direct mortality (for example, animals being hit by vehicles), and behavioral changes. The report compiles the results of studies pertinent to Little Missouri National Grassland, focused mainly on songbirds, grouse, ungulates, and aquatic communities. An example of one pattern that emerged for endemic grassland songbirds (Baird’s sparrow, chestnut-collared longspur, McCown’s longspur, and Sprague’s pipit) was that their abundance and reproductive success in the Great Plains were more consistently negatively affected by nearby oil and gas infrastructure than more widespread species. For pronghorn, the report describes the difficulty of measuring habitat selection in the presence of oil wells because these wells tend to be situated in areas of high-quality pronghorn habitat. Fragmentation of these high-value habitats by well pads and roads may in part explain why pronghorns in North Dakota have decreased with the rise in oil and gas development.
Because the effects of oil and gas development on grasslands are complex, the authors put together this GTR with the goals of: (1) summarizing the latest science to help inform management on current and potential issues, (2) providing a ready reference for experienced as well as new managers on the National Grassland, and (3) fostering lines of communication between scientists and managers so that research results can be incorporated quickly into management plans.