Investigating the Influences of Oil and Gas Development on Greater Sage Grouse
Photo of drilling rig with inset of greater sage grouse chick.
Human activities and developments can alter the amount and quality of the greater sage grouse habitats through disturbance from noise and activities; fragmentation of habitat patches; increases in invasive plants; and changes in predator populations. Survival and reproduction of sage grouse may be affected both directly and indirectly by energy development.

Project Partners

Bureau of Land Management

Colorado State University

Wyoming Game and Fish Department

Sage-Grouse Initiative

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Contact Cam Aldridge

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The sagebrush ecosystem is one of the largest ecosystems in western North America and it provides habitat for many mammal, bird, and reptile species including the greater sage grouse. Sage grouse population declines of 2% per year have occurred over the last several decades. Sage grouse need large, intact patches of habitat, so activities that break them into smaller patches effectively reduce habitat. Human activities and developments can alter the amount and quality of sage-grouse habitat in several ways. Development associated with oil and natural gas extraction is an increasing threat to sagebrush habitats as the number of wells associated with oil and natural gas extraction increase across the landscape. Construction of oil and gas wells results in the direct loss of sagebrush, but impacts have negative consequences at larger scales than the well pad and after drilling is complete, including alteration due to road and pipeline construction and changes in wildlife behavior. Factors that degrade sage-grouse habitat include noise and activities that disturb the birds, damage to vegetation from trampling, dust raised by traffic on nearby dirt roads, wildfire, prescription burns that do not take sage-grouse habitat into consideration, and more.

Our findings contribute to the growing number of studies suggesting oil and gas development has negative effects on sage-grouse populations and indicate that current regulations may only be sufficient for limiting population declines but not for reversing these trends. Additionally, areas not protected  may experience larger increases in oil and gas development and, therefore, larger declines in sage grouse populations.
 
Key Findings
  • The density of oil and gas development within 6.4 km of leks affected male sage grouse attendance at those leks.
  • Lek attendance was lower where development density was greater and vice versa.
Study Objectives
  • Model sage grouse population dynamics to identify populations contributing to statewide population increases or decreases.
  • Evaluate potential effects of climate variations and energy development on population persistence.
Graphic displaying declining lek attendance within 6.4 km of a lek in Wyoming.

Mean change (solid line) in male greater sage-grouse lek attendance within 6,400 m of a lek with increased well density. Dashed lines are 95% credible intervals. The dashed horizontal line represents a stable population. Click to enlarge.

As part of a statewide monitoring effort of sage grouse populations, the Wyoming Game and Fish and partnering agencies collected lek count data from across Wyoming. We used this survey data from 1980 to 2008 to model the effects of vegetation composition, precipitation, and oil and gas development on lek attendance. We investigated how changes in lek attendance responded to each of these factors within various distances around the leks. Because it may take several years for the impacts of development to become apparent in lek attendance because birds alive before development die and new generations move farther from disturbed areas, we included time lags of 1–4 years in our analyses.
 
Lek attendance decreased, on average, over the study period, though not significantly. When no wells were present within 6,400 m of a lek, attendance was stable over the study period. Lek attendance decreased more rapidly as well density increased and reached declines of 17.0% per year at 5.24 wells per square kilometer, the highest observed well densities, at a 4-year lag. Declines became significant when well density reached approximately 4 wells per square kilometer.
 
 

 

Photo of sage grouse at a lek in Wyoming.
Photo of greater sage grouse hen.
Photo of male sage grouse performing courtship display.

A lek is an area where sage-grouse congregate in the spring and males perform their courtship display where they can be easily seen by female sage grouse hens.

Sage-grouse are strongly dependent on sagebrush throughout their life-cycle including breeding, nesting, and brood rearing. Oil and gas development can affect survival and recruitment of sage grouse.

We studied how male sage grouse attendance at lek sites in spring was affected by oil and gas development in Wyoming.