Earth Notes: Restoring Arizona’s Grasslands

Sep 10, 2014

Arid grasslands once covered significant parts of the Southwestern states — as much as 24 million acres in Arizona, for example. American pronghorn were widespread in these open spaces, along with many other grassland-dependent wildlife species. 


But since the 1800s, land uses have greatly altered the extent and composition of the region’s native grasslands. Trees have invaded many of them, largely because of fire suppression and livestock grazing.

For pronghorn, encroaching trees represent danger: they provide cover for predators like mountain lion and coyote. Trees also out-compete shallow-rooted grasses for water, degrading grassland health. And, when trees invade travel corridors that pronghorn use to move among grassland sites, they inhibit genetic intermixing, which is essential to the long-term health of wildlife populations.

Resource managers from the Bureau of Land Management, Arizona Game and Fish Department, and Prescott National Forest have teamed up to develop the Central Arizona Grasslands Conservation Strategy. It’s focused on pronghorn recovery. But, the initiative should also benefit many other grassland wildlife species as well — from desert mule deer to golden eagles and grassland songbirds.

Since 2002, this interagency collaborative has been restoring grasslands in Agua Fria National Monument by cutting and burning encroaching junipers. More than 4,000 acres have been treated there to date.

Climate change, drought and development pose threats to many arid grasslands. But, with restoration projects like the one on the Agua Fria, at least some of these iconic wide-open spaces may maintain their health — with a little bit of human help.