Two for One: Saving Sage Grouse Also Helps Protect Mule Deer

The greater sage grouse just got some great news.

It turns out that the efforts to conserve the rare bird's habitat in Wyoming are also helping another beloved species: the mule deer. The discovery may aid efforts to save both species—each has suffered population decline in the past few decades.

Sage grouse, which spend most of their lives foraging on the ground, have been hit particularly hard by changes to their historic sagebrush habitat.

“Sage grouse are very sensitive to habitat fragmentation," said Holly Copeland, a research scientist with The Nature Conservancy in Wyoming.

Roads, ranches, residential development, and energy exploration projects have carved up the birds' habitat, causing their population to drop to as few as 200,000. As a result, the U.S. Fish and Wildlife Service declared in 2009 that the birds were candidates for protection under the Endangered Species Act.

But many feared adding the birds to the endangered species list would impact energy development in the region, so the U.S. government, 11 Western states, multiple conservation organizations, and corporations teamed up to take a different route.

The plan? Buy conservation easements—basically, agreements not to subdivide large properties—from ranchers and other property owners to protect and preserve key sage grouse habitat while leaving other areas open for energy development. Since 2010, more than 950 ranches have enrolled in the program. This, along with the addition of new grazing systems and other efforts, has protected millions of acres for use by the greater sage grouse.

In a welcome twist, all of that effort for the sage grouse ended up preserving migratory corridors for mule deer, according to a paper published this week in the journal Ecosphere.

The mule deer population in Wyoming has fallen from 564,000 to 374,000 over the past 14 years, according to the Mule Deer Foundation. Biologists have identified habitat loss and barriers to migration as two of the primary reasons for that decline.

It turns out that the same lands that have been conserved for sage grouse are critical areas for mule deer migration. The conservation easements set aside so far in Wyoming's Upper Green River Basin overlap with around 66 percent to 70 percent of mule deer migration paths, as well as 75 percent of the lands where the animals stop to eat and rest on their journey.

The two species’ habitat zones don't completely overlap, and the study doesn't include the rest of the state, but the paper shows how multiple species can benefit from the same conservation efforts.

“People have pondered whether other species would benefit from the work to protect the sage grouse,” said Copeland, the lead author of the new paper. “It hasn’t been rigorously quantified on a scientific basis until now."

She said this bodes well for many other species that rely on the same sagebrush habitat, including pronghorn antelope, Wyoming pocket gophers, horny toads, and several types of songbirds.

Study coauthor Dave Naugle, the science adviser for the Sage Grouse Initiative, said the conservation easements have not been in place long enough for the two species to start to recover their numbers, but the efforts are reducing the threat of future losses.

"What we're doing is maintaining the habitat to keep those populations in place," he said.