Scientists debate ‘magic number’ of wolves needed for species' survival

One of the biggest arguments left unresolved by last year's wolf lawsuit was the most obvious: How many wolves are enough? The U.S. Fish and Wildlife Service took the gray wolf off the endangered species list in 2009, with the caveat that at least 150 wolves and 15 breeding pairs endure in each of the three states in the northern Rocky Mountain population (Montana, Idaho and Wyoming). Recent surveys found at least 1,700 wolves in that area - more than enough to justify delisting. But a coalition of environmental groups sued the government, claiming those numbers were wrong. To survive and thrive, they argued, the population needed at least 2,000 and preferably 5,000 wolves. FWS biologists said they used the best available science to pick their number. Coalition members cited the well-established rules of conservation biology to justify their threshold. While the scientists dueled, U.S. District Judge Donald Molloy decided the case on a technicality and Congress reversed him with a budget rider. Wolves in the Northern Rockies are now delisted, but almost nobody's happy...more