In the last 30 years, only the bald eagle and a handful of other species have recovered enough to be taken off the federal government's list of threatened and endangered species. Others, like the California condor (left), require constant help from humans to survive the threats they face. In fact, the vast majority of these species are "conservation reliant," said John Wiens of the Point Reyes Bird Observatory, based in Petaluma, California, this morning. And they may never be taken off the list.
Wiens and Michael Scott of the U.S. Geological Survey in Idaho wanted to know how many of the 1954 listed species will require constant conservation to endure. They examined recovery plans issued for the species and gauged the likelihood that species could be delisted. About 80% of the species are conservation reliant and will remain on the list, they found. "We thought it would be lower," Wiens said. "We were quite astounded."
The situation is likely to get worse. Because habitat destruction and other threats are increasing, more species will probably need to be listed--adding to costs of keeping species on life support. "It may be unrealistic to think that we can maintain a growing balance sheet of conservation-reliant species," Wiens said. That means more thinking will be needed about how to prioritize funds spent on endangered species.