Draft EIS Appendix I 

Wyoming Sage-grouse Land Use Plan Amendment I-1 

APPENDIX I—DISTURBANCE DENSITY 

CALCULATION TOOL MANUAL 

The Bureau of Land Management’s (BLM) goal for any new activity or development proposal within 

core habitat areas is to provide consistent support for population management objectives of the State. 

Activities would be consistent with the strategy where it can be sufficiently demonstrated that no declines 

to core populations would be expected as a result of the proposed action. Published research suggests that 

impacts to sage-grouse leks associated primarily with infrastructure and energy development are 

discernible at a distance of at least four miles, and that many leks within this radius have been extirpated 

as a direct result of development (Walker et al. 2007, Walker 2008). Research also suggests that an 

evaluation of habitats and sage-grouse populations that attend leks within an 11-mile radius from the 

project boundary, in the context of “large” projects, may be appropriate in order to consider all seasonal 

habitats that may be affected for birds that use the habitats associated with the proposal during some 

portion of the life-cycle of seasonally migratory sage-grouse (Connelly et al. 2000). 

Based on this information, the potential for direct and indirect impacts to sage-grouse within core habitat 

areas shall be evaluated, at minimum, out to four miles from relatively small individual proposed actions. 

Effects analyses may extend out 11 miles or more from the project boundary for large-scale projects, 

depending on local knowledge and information regarding the site-specific population. The evaluation of 

“large” or “small” projects is not related to the disturbance density calculation tool (DDCT). The 

determination of size will be based on the distance at which an appropriate effects analysis under the 

National Environmental Policy Act of 1969 (NEPA) should be conducted, unless pertinent data and 

information indicates a greater distance would be appropriate. 

For the purpose of illustrating the implementation of the “large” or “small” determination within this 

policy statement, examples of relatively small actions may include, but are not limited to: minor 

exploratory natural gas well drilling proposals, individual rights-of-way (including below ground linear 

projects), vegetation treatments conducted in accordance with the sagebrush treatment protocols (see 

Integrated Vegetation Management below, and Attachment 6 – Wyoming Game and Fish Department 

Protocols for Treating Sagebrush to be Consistent with Wyoming Executive Order 2011-5), wind energy 

site testing, and sage-grouse monitoring projects. Examples of large-scale actions may include, but are not 

limited to: oil and gas field developments, wind energy farm/field development projects, large interstate 

transmission power lines, and vegetation treatments that eliminate functional habitat for sage-grouse. In 

all cases, these distances are only a suggested distance for evaluation, and project specific distances for 

evaluation can be modified based upon available data and information. Additionally, in the event that 

these measures are all adopted in a final proposal, this does not mean that the proposed activity would be 

automatically approved. BLM and U.S. Forest Service (Forest Service) must evaluate proposed actions on 

a case-by-case basis while meeting their obligations under NEPA, Federal Land Policy and Management 

Act of 1976 (FLPMA), and other applicable laws. 

Due to the evolving nature of the DDCT manual, the manual would become outdated soon after 

publication of this amendment document. To access the most up-to-date version of the DDCT manual, 

please use the following link to the WY IM-2013-035 Step-by-step Cooperative Strategy for Use of Webbased Density and Disturbance Calculation Tool at: http://web.wy.blm.gov/Wy.im/13/index.htm.