“In my experience, the wildlife service, along with a number of other federal agencies, whether it’s EPA, the Army Corps, the Forest Service or the National Park Service, are all very cautious due to the efforts on behalf of the regulated community to develop projects,” said Christina McVie, the Tucson Audubon Society’s conservation chair. “The fact that many species such as the Florida panther and the Mexican wolf have not recovered belies the argument that the act is having an adverse impact on business or serving the species it was intended to serve.”

Representatives of two conservative groups said the study didn’t adequately portray the species act’s economic impacts, particularly that of a federal review in the late 2000s that triggered major cutbacks in irrigation water deliveries in California’s Central Valley to protect the endangered Delta smelt.

The study also doesn’t cover many projects that never get off the ground because their proponents don’t want to go through the trouble of dealing with the reviews, said Brian Seasholes, endangered species director for the Reason Foundation, a libertarian think tank.