Updated

The Obama administration announced Tuesday that it intends to work through a backlog of more than 250 imperiled animal and plant species over the next six years to decide if they need protection under the Endangered Species Act.

Interior Department officials said the proposal stems from a court agreement with an environmental group, WildEarth Guardians. The agency has been sued numerous times over its handling of species as diverse as greater sage grouse and Canada lynx.

Those are included on a long list of fish, birds, mammals, plants and even snails that scientists say need greater protections.

Environmental groups have previously charged the Obama administration with doing little to improve on what they consider a dismal record on endangered species under President George W. Bush.

Through November of last year, Obama had provided Endangered Species Act protection to 51 plants and animals, an average of 25 a year. By comparison, the Clinton administration protected an average of 65 species per year, and the Bush administration listed about eight species a year.

But with too few resources to cover restoration costs and the number of lawsuits rising, Interior officials say they have been forced to place plants and animals that deserve greater protections on a waiting list, known as "candidate species." Some of those species have been awaiting review for years.

Deputy Interior Secretary David Hayes said that backlog has been made worse by lawsuits that have bogged down the Fish and Wildlife Service and prevented it from doing needed scientific reviews and restoration work.

"This plan will enable the endangered species program to function as it was originally intended," Hayes said. "Priorities are being set by plaintiffs in courts, instead of by wildlife professionals, by litigation instead of science."

Interior officials also said they plan to make initial findings on an additional 600 species for which groups have filed petitions seeking greater protections.

The agreement still needs court approval. As part of the deal, WildEarth Guardians said it will limit the number of petitions it files. The group's wildlife program director, Nicole Rosmarino, said many of those petitions were bound to end up on the candidate species list under the status quo.

"We and the government agree that the day has come to address the future of the endangered species candidates. This will be an important step toward protecting the rich biodiversity in the U.S. and stemming the extinction crisis," Rosmarino said.

However, another group involved in numerous lawsuits over endangered species said Tuesday it refused to sign the agreement with the Interior Department. Kieran Suckling with the Center for Biological Diversity said the deal leaves some of the most imperiled species, including the wolverine and walrus, "hanging in limbo for political reasons."