title: Stream Vulnerability to Widespread and Emergent Stressors: A Focus on Unconventional Oil and Gas.
abstract: Multiple stressors threaten stream physical and biological quality, including elevated nutrients and other contaminants, riparian and in-stream habitat degradation and altered natural flow regime. Unconventional oil and gas (UOG) development is one emerging stressor that spans the U.S. UOG development could alter stream sedimentation, riparian extent and composition, in-stream flow, and water quality. We developed indices to describe the watershed sensitivity and exposure to natural and anthropogenic disturbances and computed a vulnerability index from these two scores across stream catchments in six productive shale plays. We predicted that catchment vulnerability scores would vary across plays due to climatic, geologic and anthropogenic differences. Across-shale averages supported this prediction revealing differences in catchment sensitivity, exposure, and vulnerability scores that resulted from different natural and anthropogenic environmental conditions. For example, semi-arid Western shale play catchments (Mowry, Hilliard, and Bakken) tended to be more sensitive to stressors due to low annual average precipitation and extensive grassland. Catchments in the Barnett and Marcellus-Utica were naturally sensitive from more erosive soils and steeper catchment slopes, but these catchments also experienced areas with greater UOG densities and urbanization. Our analysis suggested Fayetteville and Barnett catchments were vulnerable due to existing anthropogenic exposure. However, all shale plays had catchments that spanned a wide vulnerability gradient. Our results identify vulnerable catchments that can help prioritize stream protection and monitoring efforts. Resource managers can also use these findings to guide local development activities to help reduce possible environmental effects.
authors.affiliation: Biology Department, University of Central Arkansas, Conway, Arkansas, United States of America.
authors.forename: Sally A
authors.initials: SA
authors.lastname: Entrekin
authors.affiliation: Northern Appalachian Research Laboratory, U. S. Geological Survey Leetown Science Center, Wellsboro, Pennsylvania, United States of America.
authors.forename: Kelly O
authors.initials: KO
authors.lastname: Maloney
authors.affiliation: Waterborne Environmental Inc., Leesburg, Virginia, United States of America.
authors.forename: Katherine E
authors.initials: KE
authors.lastname: Kapo
authors.affiliation: U.S. Geological Survey, Wyoming Cooperative Fish and Wildlife Research Unit, Department of Zoology and Physiology, University of Wyoming, Laramie, Wyoming, United States of America.
authors.forename: Annika W
authors.initials: AW
authors.lastname: Walters
authors.affiliation: Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas, United States of America.
authors.forename: Michelle A
authors.initials: MA
authors.lastname: Evans-White
authors.affiliation: Department of Biology, Wilkes University, Wilkes-Barre, Pennsylvania, United States of America.
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Klemow
mesh_terms: D000067071:Hydraulic Fracking; D059392:Petroleum Pollution; D018570:Risk Assessment; D045483:Rivers; D014481:United States; D014874:Water Pollutants, Chemical / Q000032:analysis*; D060753:Water Quality
chemical_list: D014874:Water Pollutants, Chemical