Biological integrity is defined as persistent and stable community composition and ecological function that can change with alterations. An inherent challenge in identifying ecological indicators is adequate data prior to ecosystem alterations, unknown interactions among alterations, and the appropriate scale to measure indicators. Oil and gas extraction is among the most common landscape disturbance that has increased in the last decade in density and geographic expanse across the U.S. in regions without a history of extraction. Disturbances associated with extraction are land clearing for supporting infrastructure, freshwater withdrawals, and possible chemical and wastewater water spills during drilling/fracturing, reuse, transport, and treatment. The well and pipeline density along with violations in a watershed are often used as indicators of biological risk at the reach (100 m) and small (<130 km2) watershed scale.
Results/Conclusions
In the Fayetteville Shale, well installation rates averaged 700 per year from 2005 through 2015. Sedimentation in streams correlated with more wells in stream catchments; 10% of all wells were within a 100m of a stream channel; and 7-15% of catchments with surface water withdrawals showed possible water stress from volumes that were not scaled to stream discharge. Together, catchment alterations from HVHF may result in biological effects. We found an increase in stream turbidity and primary production related to greater well density in catchments in some seasons and years. Macroinvertebrate filtering taxa densities and biomass increased with well density, while some caddisflies sensitive to sedimentation declined. Overall, macroinvertebrate diversity declined across a well and pasture gradient at similar rates. We will summarize the existing surface water physical, chemical, and biological responses to HVHF that are drawn from our experience in the Fayetteville Shale and associated indicators of environmental changes.