Red Canyon Ranch Selected for Ten Year Study

Red Canyon Ranch
© Jeff Vanuga

Over the last 150 years the rangelands of the arid West have undergone unprecedented change. Prior to Europeans' settlement, grasslands and shrublands were structured primarily by fire and to a lesser degree by grazing ungulates. These roles have been reversed; domestic livestock now graze the large majority of western North America, and wildfire occurs at times, frequencies, and intensities that are outside of historical norms.

The impact of this reversal is poorly understood. Now the Nature Conservancy, in conjunction with federal, state, and other non-government organizations, is launching a ten-year study on a number of Conservancy properties to determine the long-term effect of changes in the grazing and fire regimes of the Western range.

The Conservancy is unique in that it has many ranches and dozens of scientists scattered throughout the West. This gives it the opportunity to institute long-term, manipulative studies in six different landscapes in order to understand the interactions of these driving processes. Red Canyon Ranch has been selected to be one of these sites, along with others ranging from the Gray Ranch in the Malpai Borderlands of New Mexico to the Zumwalt Prairie in Oregon.

While current livestock management practices are usually in balance with present ecological conditions, this has not historically been true. The impacts of old-time overstocking practices continue to have major implications for land management, as well as on efforts to restore ecological structure and function. Livestock management has improved in recent decades, but the pace and extent of ecosystem change has been accelerating due to humans’ continued interference with natural fire regimes.

In the Southwest, long fire-free intervals due to fire suppression favor the expansion of woody species throughout grasslands and steppes that historically supported few trees. The result is dense canopies under which no vegetation will grow. Alternatively, in much of the Intermountain West, fires are much more frequent than they were historically as a result of cheatgrass (Bromus tectorum) invasion. Cheatgrass, an exotic annual, increased dramatically in these sagebrush shrublands after early livestock use reduced palatable native bunch-grasses and forbs. Native plant species do not survive the frequent fires facilitated by cheatgrass, and the system ratchets inevitably toward a cheatgrass monoculture nearly devoid of biodiversity value.

Of the major driving variables in arid ecosystems—geography, climate, fire, and grazing—only two can be manipulated by land managers; fire and grazing. Fire and grazing regimes are intimately linked by the consumption of fine fuels by livestock, therefore understanding the interaction between fire and grazing is critical as land managers attempt to restore the natural fire regimes needed to rehabilitate the nation’s arid rangelands.

The 10-year study, led by Conservancy scientists Drs. Provencher in Nevada and Unnasch in Idaho together with staff from other organizations and agencies, will initiate a large-scale research program to understand the dynamics of fire and grazing ‘at scale.’ Current understanding of our rangelands is based on research that was done at too small a spatial scale, too briefly, or both. This is simply because an individual researcher does not have the time, the ability, or the access necessary to study these processes at multiple large areas over many years.

The study will include examining the combined effect of grazing management with prescribed burns the impact of fire or grazing separately. and the exclusion of both. An extensive, observational study across an additional 30 sites scattered throughout the arid west will also take place. Scientists will be collecting the same information at all study sites, allowing for comparisons at multiple scales.
In short, the study will assess three key attributes of ecological integrity:

• hydrologic function – how does water cycle through the landscape?
• soil and site stability – what happens after disturbance?
• biotic integrity – are plants and animals functioning as a system?

The partnership of state, federal and NGO scientists who are collaborating on this proposed research are uniquely positioned to undertake such a study. Together, the members of the team have extensive experience collaborating with local communities and resource managers to develop long-term, landscape level experimental studies.

Robert S. Unnasch is Senior Ecologist for The Nature Conservancy. Throughout his 18-year career, he has focused on managing the Conservancy’s Ecological Research and Monitoring Programs. Currently he is directing the Aridlands Grazing Network, a 13-state initiative to foster cross-site learning and adaptive management throughout the West, and the Grassland Restoration Network, a multi-state initiative to foster learning and adaptive management among landscape restoration initiatives.