By Laura Zuckerman

(Reuters) - The Obama administration used flawed research in devising a plan to strip gray wolves across the continental United States of Endangered Species Act protections, and discounted evidence that failed to support it, a scientific panel said in a report released on Friday.

The U.S. Fish and Wildlife Service said last June said wolves in the lower 48 states no longer faced extinction after decades of recovery efforts and proposed removing them from the U.S. threatened and endangered species list. (Report on wolves:

Distinct wolf populations in the Northern Rockies and western Great Lakes were already delisted in recent years as their numbers rebounded in those regions.

The administration latest plan renewed a debate between supporters and opponents of wolves, which were hunted, trapped and poisoned to near extinction in the continental United States before coming under federal safeguards in the 1970s.

Ranchers and hunters blame wolves for preying on livestock and big game. Conservationists say the wolf, an apex predator, has helped restore ecosystems strained by an overabundance of wildlife such as elk and deer.

The wildlife service in August placed its nationwide wolf delisting proposal on hold after outcries by critics who claimed the government's process was slanted toward removing protections.

The agency last year asked the National Center for Ecological Analysis and Synthesis at the University of California at Santa Barbara to appoint a panel of independent scientists to review the delisting plan.

The Fish and Wildlife Service on Friday released the panel's report, which said the agency failed to use the "best available science," as required, to conclude nationwide delisting is warranted.

The government also relied on a single publication by the wildlife service that has been refuted by leading wolf experts and geneticists, and rejected data that did not support the plan, according to the report.

"Information contrary to the proposed delisting is discounted whereas that which supports the (plan) are accepted uncritically," wrote panelist Robert Wayne, a wolf geneticist at


The wildlife service on Monday will reopen the proposal for public comment for 45 days in light of the findings, which the agency is reviewing, said Seth Willey, regional recovery coordinator in Denver. A final decision is expected this year.

Willey said several wolf packs are known to exist in Oregon and Washington state, and wolves have wandered from the Northern Rockies into such states as Colorado.

The proposal in question would leave federal protections in place for the Mexican wolf, a subspecies in Arizona and New Mexico estimated to number in the 80s.

While wolves once roamed across nearly every corner of the continental United States, Willey said the Endangered Species Act does not require re-establishing a species to its full historic range in order to prevent extinction.

The comeback of wolves - which now number in the thousands in the lower 48 - is an "amazing success" tied to the nation's landmark conservation law, he said.

Conservation groups on Friday hailed the panel's findings, which are sure to be used to challenge the delisting in court if it happens.

"We've known all along there was political motivation behind the delisting proposal, and the panel's review underlined that," said Bethany Cotton, wildlife program director for WildEarth Guardians.

(Reporting by Laura Zuckerman in Salmon, Idaho; Editing by Steve Gorman and Lisa Shumaker)