This week, gray wolves in the northern Rockies lost their protected status under the Endangered Species Act for the second time in the space of a year. And what a long, strange year it's been.

There are many factors affecting the decision, of course: farmers want to protect their livestock, hunters want to be able to shoot wolves; people are scared of wolves and other large predators; and contractors want to be able to build in the northern Rockies.

First protected in 1974 when the gray wolf (Canis lupus) bordered on extinction, the northern Rockies population of the species first lost its protected status in March 2008. The logic behind the decision was that wolves had, theoretically, recovered enough that they no longer needed protection. At that time, the states of Montana, Idaho and Wyoming started preparing for wolf hunts, the first time such hunts were legal in decades.

Conservationists disagreed with the decision and sued to reinstate the wolf's endangered status. In June, U.S. District Judge Donald Molloy issued a temporary injunction against wolf hunts, but at least 106 wolves had already been shot and killed before it took effect.

Wolves went back on the Endangered Species List—for a little while—in September, when the U.S. Fish and Wildlife Service (FWS) announced it had decided to withdraw its original decision.

It didn't last. In late October, the Bush administration once again started moving forward with plans to remove gray wolves in the Rockies from the Endangered Species List. The only difference from the original plan was that wolves would retain their protected status in Wyoming, which, according to the FWS, does not have a wolf management plan or the regulatory framework that meet requirements set by the Endangered Species Act. Wolves in other parts of the country, like Oregon, South Dakota and Michigan, remain protected, as they did under the March 2008 plan.

Flash forward to this week, when the Obama administration followed through on the Bush-era plans and delisted the wolf once again (PDF). Conservation groups, as expected, lined up and announced plans to sue to reinstate that protection.

The big debate here comes over what constitutes a "recovered" population. There are currently, according to FWS, at least 1,645 gray wolves in the northern Rockies, living in 217 packs. According to Andrew Wetzler, Director of the Natural Resources Defense Council's Endangered Species Project, the recovery goals, set back when wolves first gained ESA protection in 1974, "only require 300 wolves in the tri-state area, or 10 breeding pairs in each state." During an online chat (transcript) on May 7, Wetlzer said the ideal wolf population size to prevent genetic loss is even higher than the current population: 2,000 to 2,500 individuals. Two hundred and twenty-five scientists agree, and this week sent a letter of protest to Secretary of the Interior Ken Salazar, arguing that the current wolf population is too small.

Wolf inbreeding has become a problem in at least one other part of the country. In Michigan, where just two dozen wolves live on islands in Lake Superior, the animals have developed backbone malformations due to a too-small gene pool. It's way too soon to say if that would happen elsewhere, especially since the Michigan wolves are completely isolated from any other wolves that could join their packs, but this does show that small wolf populations can be vulnerable to genetic weakness, according to a paper in this month's issue of the journal Biological Conservation. (See a slide show of the wolves—and moose—of Lake Superior's Isle Royale.)

What happens next? Chances are, we'll hear about the first new wolf shooting soon. Lawsuits by the NRDC and other groups can start up as early as next month (they are required to file a 60-day notice of their intent to sue). After that, it's anyone's guess.

Image: Gray wolf, via Wikipedia