The importance of landscape connectivity was first recognized by conservationists more than 20 years ago, when groups such as the Wildlands Network (then known as the Wildlands Project) and Yellowstone to Yukon proposed regional efforts to achieve conservation on a continental scale. The Wildlands Network seeks to create "megalinkages" of habitat down the entire length of North America and along the Eastern Seaboard; Yellowstone to Yukon envisions connections throughout more than 500,000 square miles of the United States and Canada. While many conservation biologists support them, these goals long seemed out of reach. But climate change, which is expected to force animals to move uphill and toward the poles in search of more hospitable habitat, has helped corridors gain broader traction among environmentalists, philanthropists and policy-makers. "Funders tell me, 'Every organization walking through here now mentions connectivity,' " says Kenyon Fields of the Wildlands Network.

Fields, who is based in Washington state, leads a working group through which representatives from several conservation groups attempt to include connectivity in federal land agency planning. The working group is currently battling to keep connectivity language in proposed revisions to the Forest Service guidelines, and in President Obama's America's Great Outdoors initiative. "But the real task," says Fields, "is to move the ball beyond sunny policy rhetoric and vagaries to action on the ground."

In many cases, that means gaining support not only from scientists, conservationists and agencies, but also from a broad spectrum of private landowners and other interests. In their campaign for the Path of the Pronghorn, Berger and his colleagues were careful to recruit diverse allies. They held town meetings and solicited input from locals. Ranchers and hunters, who might have opposed the corridor, signed on, as did the extractive industries in the area. One major holdout still remains -- the Bureau of Land Management, which has not enacted any additional protections for pronghorn on the portions of the corridor that cross its land. When corridor supporters met with then-Wyoming Gov. Dave Freudenthal, "he got the concept immediately," says Berger. "He told us to show him agreement was gathering from the ground up. It was appropriate and that's what we did."

Freudenthal not only backed the Path of the Pronghorn, but also took the concept to the Western Governors' Association, a coalition of 19 Western states and three Pacific islands. In 2007, just before the Path of the Pronghorn got Forest Service protection, Freudenthal championed a WGA policy resolution called  "Protecting Wildlife Migration Corridors and Crucial Wildlife in the West." Since then, a WGA habitat council has been working to create user-friendly online tools for corridor planning, coordinating region-wide information on wildlife habitats and building a West-wide database of existing corridors. It's easier said than done: States collect data on wildlife within their boundaries, but in different ways, and states can be territorial about their data. Nor is there any legal requirement that land managers incorporate any of this information. Nevertheless, the WGA recently unveiled Arizona's Habimap.org and the Southern Great Plains Crucial Habitat Assessment Tool. This will help coordinate efforts in Colorado, Kansas, New Mexico, Oklahoma and Texas to model crucial habitat, including corridor connections, for the lesser prairie chicken, which is in the initial stages of listing under the Endangered Species Act.

The Western states can draw inspiration from at least one previous collaborative effort to protect migrations on a grand scale. In 1986, the U.S. Fish and Wildlife's Division of Bird Habitat Conservation established a program to protect migratory birds across North America. Canada and the U.S. signed a North American Waterfowl Management Plan that included several regional efforts. One of the most successful of these is the Lower Mississippi Valley Joint Venture, in which not just federal agencies but also states, nonprofits, private landowners and hunting organizations like Ducks Unlimited share scientific data and collaborate on protection of migratory flyways over multiple jurisdictions. Sam Hamilton, the former Fish and Wildlife Service director who died unexpectedly in 2010, expanded this model to include multiple species. He established Landscape Conservation Cooperatives (LCCs), defined by ecoregion across the nation and even over our borders, to promote landscape connectivity and interjurisdictional cooperation. These LCCs are just getting under way, beginning, as such endeavors often do, by aligning models and datasets so they can be used by everyone involved.