Gateway West Transmission Line Draft EIS 

Appendix J 

Framework for Sage-Grouse Impacts Analysis for Interstate 

Transmission Lines 
Gateway West Transmission Line Draft EIS 

Appendix J – Framework for Sage-grouse Impacts J-1 

Analysis for Interstate Transmission Lines 

Framework for Sage-grouse Impacts Analysis for 

Interstate Transmission Lines 

05-17-2011 

(1) Evaluation of Direct and Indirect Impacts- This portion of the overall SG Impacts 

Assessment Framework addresses project-related habitat impacts that bear directly on listing 

factors considered by the U.S. Fish and Wildlife Service (FWS) when evaluating the need to 

provide full listing protection under the Endangered Species Act (ESA). 

A starting point for this analysis is a thorough review of the threats assessment/five factor analysis 

that FWS conducted as part of the March 23, 2010 (75 FR 13910), listing of the SG as a Candidate 

under ESA. An evaluation of all potential threats to SG and SG habitat from the transmission line 

should be conducted incorporating the latest available scientific information—most of which is 

referenced in the FR notice itself. 

Of particular importance is the synthesis evaluation of all potential threats of the project that 

operate cumulatively to impact SG populations and habitat in a way that is not adequately 

evaluated by examining threats independently. The project proponent should look to the FR 

cumulative threats assessment summary as an example of how to fully analyze impacts associated 

with the proposed project. Reference to additional scientific information published since the 

issuance of the FR is available on the FWS website and should be incorporated into the analysis. 

An analysis of sage-grouse populations that attend leks within 18km of the project is a critical 

component of an indirect impacts analysis for the species. Sage-grouse that attend leks up to 18km 

from the project may be indirectly affected by the loss of habitat functionality during other seasons 

of the year (Connelly et.al. 2000). The construction of a transmission project or other linear facility 

may pose additional hindrance of seasonal migration patterns or avoidance of important seasonal 

habitats once used extensively by local sage-grouse populations. Qualitative and quantitative 

measures of habitat change must be considered in describing the potential impacts of the project. 

In the context of managing a species that requires such a large landscape of habitats to meet their 

life-cycle needs, and the nature of the proposed disturbance, it is reasonable to make some 

assumptive predictions about the relative impacts within 18km. 

(2) Habitat Equivalency Analysis (HEA)- HEA is a method of quantifying the permanent or 

interim loss of habitat services from project related impacts. HEA provides a scientific-based, 

peer-reviewed method of scaling compensatory mitigation requirements, and has been used by 

federal regulatory agencies including the FWS and National Oceanic and Atmospheric 

Administration. The HEA is not meant to be an impacts analysis in and of itself; rather, it is a way 

to objectively determine quantity of project-related habitat impacts and provides the quantity and 

type of mitigation necessary to offset loss of habitat services as a form of output. 

The HEA will be conducted generally following the Choke Cherry/Sierra Madre Project HEA as an 

example. This example will provide a general framework for the HEA: details associated with the 

proposed transmission line project to be incorporated into the HEA will be determined by the 

project proponent in collaboration with State and Federal Agency biologists. 
Gateway West Transmission Line Draft EIS 

Appendix J – Framework for Sage-grouse Impacts J-2 

Analysis for Interstate Transmission Lines 

HEA is a process that requires close collaboration among the project proponent and State Agencies 

in states sustaining most of the impacts to populations and habitat (like Wyoming and Idaho) as 

well as FWS and BLM biologists to ensure adequacy of analysis and a corresponding final product. 

Other impacted states are expected to play an “advisory” role reviewing the HEA and ensuring 

consistency with their respective states as well (e.g., UT, NV, CO, and others depending upon the 

project). Building models associated with the HEA process must be done in close coordination 

with agency biologists in order to address concerns, questions, assumptions, and issues as they 

arise. 

Agency biologists recognize the need for the incorporation of data and information the HEA 

models that the project proponent may not currently have. Agency biologists will work with 

project proponents to obtain such information to the extent they can (e.g., habitat maps; adequate 

vegetation data)—again, reiterating the need for an interactive approach between the project 

proponent and agency biologists in order to ensure adequate completion of the HEA. 

The initial starting point for evaluating direct and indirect impacts to SG habitat will be 18km 

either side of the proposed transmission line, addressing impacts to roughly 98% of nesting hens 

according the best available scientific information. Any deviation from this starting point must be 

supported by scientific literature: agency biologists can direct the project proponent to recently 

published literature on this topic which the project proponent is encouraged to use. 

(3) Addressing Direct Loss of Birds- While the currency of HEA is in terms of habitat acreage 

and/or dollars associated with what is essentially an economic analysis, a fundamental concern of 

all agency biologists is the need to address the impact (i.e., “take” including mortality, harm, etc.) 

to SG populations and the issue of their replacement. This piece of the overall SG Impacts 

Assessment Framework is an important contribution to the rangewide jeopardy analysis conducted 

as part of the informal conferencing process for this Candidate species. Additionally, addressing 

impacts to populations provides key information needed for completing any potential future formal 

Section 7 consultation that would be required if the SG is ultimately listed under ESA during 

project development, thereby significantly streamlining this process. 

FWS is actively working on this issue as it relates to rangewide SG conservation. There are two 

ways that the project proponent is expected to help resolve this concern: 

a) Work closely with FWS and State Agency Biologists to develop an approach to address loss 

of birds from project-related impacts and their replacement; 

b) Contribute financially to research projects that have been designed specifically to address 

this issue 

(4) Mitigation- Until an impacts analysis has been conducted in coordination with agency 

biologists—leading to an adequate understanding of impacts to SG populations and habitat—the 

issue of mitigation will not be addressed. However, when discussion and evaluation of mitigation 

does begin, it is with the understanding that mitigation ratios across state lines will remain the 

same. That is, a bird in Wyoming is equivalent to one in Idaho; an acre of nesting habitat in WY is 

worth as much in Idaho; etc. 
Gateway West Transmission Line Draft EIS 

Appendix J – Framework for Sage-grouse Impacts J-3 

Analysis for Interstate Transmission Lines 

Calculating Density of Disturbance within Key1 Habitat 

Once the Alternatives Analysis is complete and a preferred alternative has been selected, an 

additional site-specific evaluation of density of disturbance within Key Habitats/Core Areas may be 

conducted. The purpose of this evaluation is to evaluate opportunities to: minimize density of 

disturbance within Key Habitats/Core Areas that are outside the designated disturbance corridor 

identified in the Wyoming Governor’s Executive Order 2010-4; and restore and/or enhance 

important sage-grouse habitat as a part of project-related mitigation. These site-specific habitat 

evaluations also will enable BLM to: (a) demonstrate compliance with the Greater Sage-Grouse 

Habitat Management Policy on Wyoming BLM Administered Public Lands including Federal 

Mineral Estate (IM WY-2010-012); and (b) demonstrate consistency with the Greater SageGrouse Core Area Protection, Wyoming Governor’s Executive Order 2010-4. 

The overall goal of a Sage-Grouse Key Habitat/Core Area Strategy within both Wyoming and 

Idaho is to limit the density and duration of disturbances and restrict activities within Key/Core 

Areas sufficient to ensure the long-term conservation and management of sage-grouse within each 

state. To this end, the Density Disturbance Calculation (DDC) is a tool designed to measure habitat 

loss within the Key Habitat/Core Area. In particular, it is used to determine—in terms of 

management actions— how the project related disturbance can be limited to no more than 5% loss 

of habitat and result in no more than an average of one disturbance per 640 acres. 

The DDC calculates habitat loss in Key Habitat/Core Areas beyond which scientific research has 

shown negative population level effects will occur. To accomplish this, the following evaluation 

will be conducted. 

Step 1: Determination of leks that will be used in the site-specific evaluation: 

Place a four-mile boundary around the outer project boundary (as defined by the proposed area of 

disturbance related to the project, i.e., 150ft Right of Way, or similar). All occupied and 

undetermined sage-grouse leks located within four miles of the outer boundary of the project, and 

within Key Habitat/Core Areas, the will be considered in the DDC. 

Step 2: Determine the DDC area size and configuration: 

A four-mile boundary placed around the perimeter of each lek identified in Step 1 and the area 

within the boundary of the leks, plus the four-mile project boundary, creates the DDC area for the 

project. 

Step 3: Density of disturbance habitat evaluation: 

Disturbance will be evaluated for the DDC area as a whole, as well as for individual leks within the 

DDC area. Any portion of the DDC that falls outside Key Habitat/Core Area will be removed from 

this portion of the evaluation for Wyoming. 

Disturbance Calculation: Total acres of “disturbance” within the DDC area will be determined 

through an evaluation of: 

a. Existing and Proposed disturbance—sage-grouse habitat that is disturbed by existing 

anthropogenic features or activities (e.g., transmission lines, distribution lines, wind 

development, oil/gas wells/facilities, geothermal, communication towers, pipelines, paved 

roads, and others)— and wildfire, including the full 150ft ROW of the proposed action; 
Gateway West Transmission Line Draft EIS 

Appendix J – Framework for Sage-grouse Impacts J-4 

Analysis for Interstate Transmission Lines 

 Additional guidance and information regarding how to “count” the number and acres of 

existing disturbances is available. Please request additional information regarding this 

issue from Idaho Fish and Game biologists the Habitat Protection Section (HPS) of the 

Wyoming Game and Fish Department. 

b. Approved permits (i.e., any state or Federal permits providing approval for on the ground 

actions) for projects not yet implemented or constructed. 

Habitat Disturbance Evaluation: For projects that will result in disturbance of more than 5% of the 

DDC area, it may be advantageous for the project proponent to map the full extent of sage-grouse 

habitat within the DDC area in order to reduce this percentage. If this is done, it will be conducted 

to identify: 

a. “Suitable Habitat” and “Marginal Habitat” using BLM’s Habitat Assessment Framework 

(HAF) and unsuitable habitats within the DDC area. 

b. Sage-grouse evidence of use of suitable habitats (seasonal use, densities based on best 

available information) 

c. Priority restoration areas (which could reduce the existing disturbances to below the 5% 

threshold) for example: 

i) Areas where plug and abandon activities on retired oil and gas wells will eliminate 

disturbance 

ii) Areas where old reclamation has not produced suitable habitat 

d. Areas of invasive species 

e. Lands where other conservation assurances are in place (e.g., CCAA, easements, habitat 

contract, etc.) 

Step 4: Determination of existing and allowable suitable habitat disturbance: 

Acres of disturbance within suitable habitat divided by the total suitable habitat within the DDC 

area, multiplied by 100, equals the percent of disturbed suitable habitat within the DDC area. 

Subtracting the percentage of existing disturbed suitable habitat from 5% equals new allowable 

suitable habitat disturbance until plant regeneration or reclamation reduces acres of disturbed 

habitat within the DDC area. 

1 Key Habitat Definitions. For purposes of the Density of Disturbance Analysis for Gateway West, “Key 

Habitat” areas in Wyoming will correspond to the State of Wyoming’s identified Core Population Areas 

(version 3), and in Idaho the definition will encompass all of the following habitat types identified on the 

Idaho Sage-grouse Habitat Planning Map: 

Key Habitat: Areas of generally intact sagebrush that provide sage-grouse habitat during some 

portion of the year. 

Potential Restoration Area Type I (Also referred to as R1). Perennial Grasslands: Sagebrush-limited 

areas characterized by perennial grass species composition and/or structure that should provide 

suitable potential nesting habitat in the future, once sufficient sagebrush cover is re-established. 

Potential Restoration Area Type II (Also referred to as R2). Annual Grasslands: Areas dominated or 

strongly influenced by invasive annuals such as cheatgrass (Bromus tectorum), medusahead rye 

(Taeniatherum caputmedusae) or similar species. 

Potential Restoration Area Type III (Also referred to as R3). Conifer Encroachment: Areas where 

junipers and/or other conifer species are encroaching into sage-grouse habitat areas.