Oil and gas wells and pipelines on U.S. wildlife refuges: challenges for managers.

The increased demand for oil and gas places a burden on lands set aside for natural resource conservation. Oil and gas development alters the environment locally and on a much broader spatial scale depending on the intensity and extent of mineral resource extraction. The current increase in oil and gas exploration and production in the United States prompted an update of the number of pipelines and wells associated with oil and gas production on National Wildlife Refuge System (NWRS) lands. We obtained geospatial data on the location of oil and gas wells and pipelines within and close to the boundaries of NWRS lands (units) acquired as fee simple (i.e. absolute title to the surface land) by the U.S. Fish and Wildlife Service. We found that 5,002 wells are located in 107 NWRS units and 595 pipelines transect 149 of the 599 NWRS units. Almost half of the wells (2,196) were inactive, one-third (1,665) were active, and the remainder of the wells were either plugged and abandoned or the status was unknown. Pipelines crossed a total of 2,155 kilometers (1,339 miles) of NWRS fee simple lands. The high level of oil and gas activity warrants follow up assessments for wells lacking information on production type or well status with emphasis on verifying the well status and identifying abandoned and unplugged wells. NWRS fee simple lands should also be assessed for impacts from brine, oil and other hydrocarbon spills, as well as habitat alteration associated with oil and gas, including the identification of abandoned oil and gas facilities requiring equipment removal and site restoration.