Shale gas and other oil and gas development can disturb landscapes on a large scale, affecting how ecosystems are built and work, local economies, and the health and range of important plants and animals. It has also changed land use and brought more people, straining infrastructure and potentially affecting the human environment.
The overlooked footprint
Often overlooked is the physical footprint of gas exploration, production and delivery on the land surface. Much of what ecosystems do, and the goods and services they provide, depends on how their parts are naturally arranged across the landscape. Shale gas development changes the pattern of land use and land cover, and with it the shape, form and function of landscapes, including many biological responses.
Figure 1: Forest in Washington County, Pennsylvania, cut by the roads, well pads and pipelines of unconventional gas (top pair) and conventional gas (bottom pair). USGS.
Demand for energy has opened many opportunities in the Appalachian basin. Deep shale drilling alongside conventional gas has brought a flurry of wells, roads, pipelines and other infrastructure. More than 100,000 permits for oil, coal-bed methane, Marcellus and Utica shale gas and other wells, with their infrastructure, now saturate much of the landscape, and the sheer scale of development directly affects how the land and its ecosystems work.
Figure 2: Oil and gas permits in the Appalachian region, 2004–2010; Marcellus and Utica shale, coal-bed methane and oil well permits total over 100,000. USGS.
What the USGS is doing
The USGS is mapping the surface disturbance by digitising features from high-resolution aerial images (the National Agriculture Imagery Program) into a geographic information system, then combining them with land-cover data to calculate landscape metrics, measures that show how development affects natural resources, habitats and ecosystem functions. That lets scientists judge the effects on forests and other resources so that decisions about energy development are better informed.
Figure 3: Increase in the number of forest patches by watershed, 2001–2010, showing growing fragmentation in Bradford and Washington Counties, Pennsylvania. Base map from the National Atlas. USGS.
Key science questions
- How much disturbance does natural gas development cause, and how has it changed land cover over time?
- How is it affecting the condition of forests and other ecosystems: their structure, scale, distribution and course of regrowth?
- What are its cumulative effects, on temperature, albedo, carbon storage, long-term land use and more?
First results
The first step, documenting how much disturbance gas development has caused and where, is complete. That record underpins studies of effects on fish, local and migratory wildlife, runoff and erosion, the spread of invasive species, biodiversity, surface and groundwater quality, watershed conservation, and regional programmes such as the Chesapeake Bay Watershed Agreement. Reports are at pubs.usgs.gov (search "Landscape consequences of natural gas extraction"), and the disturbance data for 2004–2010 are on ScienceBase.
What remote sensing can add
Remote sensing gives a bird's-eye view and is the most time- and cost-efficient way to map these changes. It could also help with environmental impact assessments; detecting methane leaks; finding abandoned wells; restoration and monitoring over time; finding watershed boundaries and sites for wastewater treatment; tracking regrowth after operations end; spotting invasive species moving into disturbed ground; checking mitigation; guiding field crews to the most fragmented habitats; and finding places where disturbance could worsen hazards such as mudslides.
Why it matters
Deep resources such as the Marcellus Shale have produced a great deal of energy but are changing the landscape at an unprecedented rate. Mapping the disturbance is the first step in assessing its long-term effects, and will help policymakers decide about future development.
Sources
- E. T. Slonecker, L. E. Milheim, C. M. Roig-Silva and S. S. Kalaly, Effects of Hydrocarbon Extraction on Landscapes of the Appalachian Basin, U.S. Geological Survey Fact Sheet 2015–3064. https://pubs.usgs.gov/publication/fs20153064
Licence: CC0 1.0 (public domain) · Adapted from pubs.usgs.gov
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