A preliminary federal plan to ring sensitive wildlife habitat with a network of coal-bed methane operations could irreparably degrade the rugged Fortification Creek area of the Powder River Basin and reduce a rare prairie elk herd, according to conservationists.

Eight conservation and landowner groups want the Bureau of Land Management to consider more mitigation measures. This week the groups filed an administrative appeal to the U.S. Interior Department's Board of Land Appeals, hoping to force the BLM to take more measured steps before allowing the development to move forward.

"Given the recognized extremely important environmental values of the Fortification area, and particularly the value of its unique herd of elk, these impacts will clearly constitute unnecessary or undue degradation of the public lands," the groups argued in a 20-page "statement of reasons" for filing their appeal.

The groups include the Powder River Basin Resource Council, Wyoming Outdoor Council, Wyoming Wildlife Federation and National Wildlife Federation.

"I've been going into the Fortification since 1962," said Robert Sorenson, a Spotted Horse rancher and landowner. "The wildness, beauty, ruggedness and hunting opportunities amaze me. It is unique and virtually the only unspoiled area left in an increasingly industrialized Powder River Basin."

Wildlife biologist William Alldredge, who reviewed the BLM's permitting documents and analysis for the groups, noted, "Because of the isolated nature of the Fortification Creek elk habitat, impacts resulting from CBM development will be very difficult to regulate or mitigate," according to the filing.

Casper geologist Gene George is a coal-bed methane industry consultant familiar with the area. He said the Fortification Creek area overlies perhaps the biggest concentration of coal-bed methane reserves in the basin -- nearly 2 trillion cubic feet of gas.

According to the BLM, some 371 conventional oil and gas wells already exist in the proposed development area. The proposed coal-bed methane plan, so far, would commingle an additional 158 wells for a total of 529 wells in the area.

George said developers have worked closely with BLM to use existing corridors and group new facilities together in order to minimize the footprint of additional activity.

George also said the elk herd in the area is much larger than the target size by the Wyoming Game and Fish Department, due in part to large tracts of private land in the area.

"As far as hunting goes, there's so much private land in there that you can't go in and hunt the elk," George said.

Mark Winland of the Wyoming Wildlife Federation said coal-bed methane development is much more dense a pattern on the landscape than conventional oil and gas that's already in the area.

"The BLM itself acknowledges that Fortification Creek elk are not using suitable habitat within 1.7 miles of existing development to the degree expected, yet they have approved development right up to their elk range boundary," Winland said. "This elk herd is literally surrounded by development, with more development slated to proceed into its range from all directions."

Winland said the groups object to the BLM's current "piecemeal" planning approach to coal-bed methane development in the area. Instead, a full environmental impact statement is in order, Winland said.

"What I really think could be accomplished by doing an EIS is unitizing the field," Winland said. "If we want to be responsible to the resource there, then we need to come up with some more creative solutions."

The Petroleum Association of Wyoming issued a statement Wednesday objecting to the notion that proposed development would harm the Fortification Creek elk herd.

"The groups' claim that this small development of 100 wells would severely impact a natural elk herd is erroneous," PAW said in a prepared statement. "This herd is not a natural herd, as it was introduced as a study many years ago. In fact, the herd is over triple the original target size."

Energy reporter Dustin Bleizeffer can be reached at (307) 577-6069 or dustin.bleizeffer@casperstartribune.net.