An evaluation of the 1988 BLM Pinedale Resource Management Plan, 2000 BLM Pinedale Anticline Final EIS and Recommendations for the current revision of the Pinedale Resource Management Plan

Publication Information

Peter Aengst
Scot Groene
Kelly Matheson
Publication Date: 2003-01
Tags: WLCI Agency Report

The Upper Green River Basin (UGRB) generally refers to the area north of Interstate 80, west of the Wind River Range, east of the Wyoming Range, and south of the Gros Ventre Range. The UGRB encompasses approximately 8,000 mi2; nearly 8% of the surface area in Wyoming. Historically, this sagebrush-dominated basin was occupied by a variety of ungulate species, including mule deer, elk, moose, bighorn sheep, pronghorn, and bison. Aside from providing large amounts of year-around habitat for wildlife, the mid-elevation (<7,600 ft.) basin serves as a natural corridor and winter range for migratory animals that occupy the surrounding mountain ranges.

Today the UGRB continues to support the largest, most diverse ungulate populations in the Rocky Mountain region. The Sublette mule deer and pronghorn populations (herd units), managed by the Wyoming Game and Fish Department (WGFD), cover the core of the UGRB. The WGFD manages these two herd units to meet numerical objectives of 32,000 and 48,000, respectively. While the areas occupied by these two herd units are fairly large in size, wintering areas available to mule deer and pronghorn in this region are often restricted and relatively small in size. Nonetheless, UGRB winter ranges support more than 10% of total mule deer and pronghorn in Wyoming. The Sublette herd unit alone supports more pronghorn than any western state, except Colorado (~70,000) and Montana (~55,000). Additionally, mule deer and pronghorn migrations within the UGRB are among the longest in North America, often reaching or exceeding distances of 100 miles.

Ungulate populations of the UGRB are valuable resources, both biologically and socially. While these populations summer over vast portions of western Wyoming, they rely on limited amounts of winter and transition range in the UGRB. Most of the winter and transition ranges occur on federal lands administered by the BLM, and must be balanced with other land uses, such as livestock grazing, recreation, and energy development. Negative impacts resulting from disturbances or habitat loss in winter or transition areas in the UGRB will not likely be localized; rather they will be evident across western Wyoming in the summer ranges these ungulate populations occupy. Of particular concern are the potential impacts to these populations from increased natural gas production and development in the UGRB.

The Pinedale Field Office of the Bureau of Land Management (BLM) announced on February 25, 2002 its intention to revise the Pinedale Resource Management Plan. The Pinedale Resource Area contains significant reserves of natural gas currently targeted for development. The Pinedale Resource Area also contains winter ranges that support an estimated 32,000 mule deer from five different mountain ranges and thousands of pronghorn, including some from as far away as Grand Teton National Park (Sawyer and Lindzey 2000, 2001). To provide informed comments during the revision of the Pinedale Resource Management Plan, The Wilderness Society, Wyoming Outdoor Council, and Greater Yellowstone Coalition contracted with Western EcoSystems Technology, Inc. to analyze the existing Pinedale RMP and the Pinedale Anticline EIS, identify potential oiland gas impacts on ungulates, and provide recommendations for mitigation and monitoring by focusing on the following main sources of information:

• Literature Review – We reviewed published and peer reviewed articles, theses, and gray literature on antelope, mule deer, and elk that address the issue of impacts of habitat fragmentation and winter range disturbances from road building and/or oil and gas development activities. Our reviews included biological/ecological and design and statistical aspects of the literature, where appropriate.
•    Review of the Pinedale Resource Management Plan and the Pinedale Anticline Project EIS – We reviewed relevant chapters of the existing Pinedale Resource Management Plan (RMP), Pinedale Anticline EIS, and pertinent technical appendices and monitoring reports.
• Upper Green River Basin Reports and Discussions with Local Biologists and Researchers – We reviewed relevant WGFD monitoring reports, annual surveys, and special reports that pertained to ungulate populations and habitat in the Upper Green River basin, including Wyoming Cooperative Fish and Wildlife Research Unit reports; and, we conducted discussions with agency managers/biologists and academic researchers involved in the study of ungulate numbers, movements and habitat issues in the Upper Green River basin.


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