Measures taken to conserve sage grouse in Wyoming also benefit mule deer migration routes, according to a new study published Monday in the online journal Ecosphere.
The research was conducted by scientists from The Nature Conservancy (TNC), the University of Wyoming (UW), Western Ecosystems Technology Inc., the University of Montana and the U.S. Geological Survey.
Conservationists long have speculated that protective measures for sage grouse also benefit the more than 350 other species that inhabit sagebrush ecosystems, but this study is the first to quantify the “umbrella” benefits of those actions for migratory mule deer. Those measures include Wyoming’s sage grouse “core area” policy, which limits development in the state’s key grouse habitat, as well as conservation easements, agreements with private landowners to limit development.
“This study underscores the simple idea that keeping sagebrush habitats intact through Wyoming’s core area policy and conservation easements will have additional benefits for mule deer habitat,” says Holly Copeland, a research scientist with The Nature Conservancy in Wyoming and lead author of the paper. “We are excited by our findings but caution that there are gaps in mule deer conservation, especially outside of core areas, where future development may become more concentrated, potentially resulting in impacts to migrating deer.”
Sage grouse conservation measures in Wyoming provide “umbrella” benefits for other sagebrush-dependent species, scientists say. (Scott Copeland photo)
Both sage grouse and mule deer, two iconic species of the American West, have seen significant population declines in recent years, as a result of drought, energy and residential development, and other habitat fragmentation. Wyoming’s core area policy is a unique and proactive effort to avoid a federal Endangered Species Act listing for the grouse. Montana recently adopted a plan similar to Wyoming’s, and several other states in sage grouse range are exploring adopting similar plans.
The study published today examined Wyoming’s Upper Green River Basin, where there are substantial but declining grouse and mule deer populations. Researchers found that areas identified as core grouse habitat in this region overlap with winter range, stopover areas and migration corridors used by deer — and that grouse core-area provisions are generally sufficient to limit impacts on deer as well as grouse. Those provisions primarily include restrictions on surface disturbances for activities such as oil and gas drilling.
In addition, land trusts have purchased a significant number of voluntary conservation easements on private lands in the area, limiting development. Statewide, more than $100 million was invested from 2008 to 2012 for conservation easements with an emphasis on sage grouse conservation.
“The study results are heartening, because they show that benefits of sage grouse conservation by many private and public stakeholders in Wyoming go even further than we first realized,” says Dave Naugle, paper co-author and science adviser for the Natural Resources Conservation Service’s Sage Grouse Initiative.
The project was conducted in collaboration with researchers at the Wyoming Migration Initiative. Based at UW, this new program has been mapping and evaluating the threats to big game migration routes throughout Wyoming.
“Much of U.S. Forest Service lands are essentially protected, and beyond that we found current sage grouse conservation policy and easements doubled existing protections for mule deer migration routes,” says Matt Kauffman, director of the Wyoming Migration Initiative under a dual appointment with the USGS and UW’s Department of Zoology and Physiology. “And conservation easements can address site-specific conservation needs of migrating mule deer, representing a critical piece of the conservation puzzle.”
Still, many important mule deer habitats lie outside of grouse core-area boundaries, the paper says. In other parts of Wyoming, the overlap of grouse core areas and mule deer habitat may be smaller, more fragmented or nonexistent.
“Ultimately, conserving deer migration routes requires consideration of corridors critical to mule deer in land-use planning,” Kauffman says. “The lack of formal identification and protection of migration corridors as areas recognized by state and federal agencies — in Wyoming and the West — is a gap in our current wildlife management policy.”
The study was funded by the NRCS-led Sage Grouse Initiative, Knobloch Family Foundation, the Kaplan Family Foundation, and the Mule Deer Foundation.
Holly Copeland, The Nature Conservancy, (307) 335-2129
Matt Kauffman, University of Wyoming, (307) 766-6404
Dave Naugle, Sage Grouse Initiative Science Adviser & University of Montana, (406) 240-0113
Image courtesy Sage Grouse Initiative