Many grassland bird species in the Bakken shale region, including some seriously declining populations, are displaced from their habitats as a result of oil and gas development, according to new U.S. Geological Survey research.
During 2012-2014, USGS and U.S. Fish and Wildlife Service scientists studied Bakken grassland sites in northern North Dakota containing oil well pads, which are the gravel surfaces that house all oil extraction infrastructures. Overall, grassland birds avoided areas within 150 meters, or about 492 feet of gravel roads, 267 meters (about 876 feet) of single-bore well pads and 150 meters of pads with more than one well. These results suggest that detrimental effects of oil extraction on habitat extend considerably beyond the immediate oil well sites.
“Quantifying environmental degradation caused by oil development is a critical step in understanding how to better mitigate harm to valuable wildlife populations,” said USGS scientist Sarah Thompson, the lead author of the report. “Our findings can help managers and developers determine the best locations for future infrastructure.”
The study focused on sites developed with unconventional methods, such as horizontal drilling and hydraulic fracturing, or fracking. The most commonly detected species were the grasshopper sparrow, Savannah sparrow, clay-colored sparrow, bobolink, chestnut-collared longspur, western meadowlark, brown-headed cowbird, Baird’s sparrow, Sprague’s pipit and red-winged blackbird.
Specific findings include:
Individual species showed varying tolerance for oil wells.
Reduced population densities of the Baird’s sparrow, chestnut-collared longspur and grasshopper sparrow were observed as far as 550 meters from single-bore wells, which were the farthest distances surveyed.
Clay-colored sparrows and brown-headed cowbirds were tolerant of oil-related infrastructure.
Sprague’s pipit, which is a candidate species for listing under the Endangered Species Act, showed reduced density within 350 meters of single-bore wells.
“Our findings suggest that reducing new road construction, concentrating wells along developed corridors, combining numerous wells on multi-bore pads and placing wells near existing roads could help minimize loss of suitable habitat for birds,” Thompson said.
The Bakken oil-producing regions of North Dakota, Montana and Canada are home to a particularly high density and diversity of grassland bird species that are declining across North America.