STEVE INSKEEP, HOST:
The United States military manages about 30 million acres of land across this country. That's a combined area bigger than the state of Pennsylvania. Large portions of that land are critical habitat for rare species. And environmentalists see an opportunity here. Here's Will Stone of member station KJZZ in Phoenix.
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WILL STONE, BYLINE: A bombing range may seem like the last place to find pockets of undisturbed ecosystems. But take a flight around the Barry M. Goldwater Range outside Phoenix and you'd be hard-pressed to find scorched earth.
IAN DOWDY: It's one of the best places for a habitat for a Sonoran Desert species.
STONE: Ian Dowdy is riding in a small prop airplane. Below, the arid valley stretches across wrinkled mountains into farmland, finally giving way to a succession of subdivisions. Dowdy is a fan of what the military does here.
DOWDY: The only operate and use about 5 percent of this entire ground. But the rest of it remains wild and open and available for wildlife.
STONE: That link between the environment and military is what Dowdy's organization, the Sonoran Institute, hopes to leverage. It's spearheading a plan that would restrict development on pieces of public land around the range, mostly by designating them as federal conservation areas. Dowdy says if you compare the flight corridors for jets to those used by wildlife on the ground...
DOWDY: The lines are very similar. So we see a mutual benefit here between protecting the landscape under the military's overflight areas and protecting the landscape for wildlife to connect from one place to another.
STONE: The danger, especially in a place of rapid growth like Arizona, is that development springs up around military installations, eventually hampering training operations. That's not just a national security issue. It's an economic one. The military generates about $9 billion a year for Arizona's economy.
FRED PEASE: The more acreage you have, the more flexibility you have to change your mission.
STONE: Fred Pease is a retired Air Force official who oversaw the management of ranges throughout the U.S. About 400 threatened and endangered species are found on Department of Defense land. The reason - wildlife take refuge in the best remaining habitat. This dynamic leads Pease to ask...
PEASE: At what point does this thing become a wildlife refuge and no longer adequate for training?
STONE: Maintaining open habitats around bases and ranges, he says, could ease that burden.
PEASE: Conservation folks are realizing that, hey, you know, some of these military lands are really great, but we shouldn't put all the pressure on them.
STONE: But in an era when public land is an increasingly contentious issue in the West, the proposed legislation behind this plan faces an uphill battle. Paul Gosar is a Republican congressman whose district borders the Goldwater Range.
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PAUL GOSAR: Now, I think when we go to Sonoran Desert, we're going to find a lot of obstinance right there. And the reason being is, is the federal government can't take care of its own lands.
STONE: Gosar says there are already tools for managing environmental issues on military land. And he won't support any new regulatory hurdles, which could impact mining and other economic interests.
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GOSAR: There's not going to be any new designations other than maybe presidential, and then they'll get a fight on it.
STONE: Gosar is referring to a national monument designation. That's how about half a million acres on the range was set aside in 2001 by President Bill Clinton.
Back on the plane, conservationist Ian Dowdy points to a piece of unprotected habitat next to that monument. A freeway is slated to go there, he says.
DOWDY: What we tried to do is put together a plan that would allow something like a freeway to pass through here while maintaining a wildlife connectivity.
STONE: That's not the case for all the land. Some would be wilderness and allow for very little human activity, say, for fighter jets flying overhead. For Dowdy, these are the trade-offs that make up a realistic conservation plan in a place such as Arizona. For NPR News, I'm Will Stone in Phoenix. Transcript provided by NPR, Copyright NPR.