The Sagebrush Cooperative

Management Issues: Grazing

In the late 1800s and early 1900s, an estimated 26 million cattle and 20 million sheep were grazing on western rangelands (Wilkenson 1992). In the Great Basin, excessive or inappropriate grazing and little to no management altered the relative proportions of shrubs, grasses, and forbs of the local plant communities in less than 10 to 15 years (Hull 1976). Along with these changes, increased opportunities for invasion and dominance of non-native grasses and forbs, fire suppression, in some cases, decline in site potential through loss of topsoil further degraded this ecoregion (Miller and Eddleman 2001). The combination of historic overgrazing and fire suppression, followed by invasion of weedy annual grasses such as cheatgrass, greatly altered natural fire cycles in many sagebrush steppe habitats. Landscapes formerly comprised of mosaics dominated by bunchgrasses and forbs became disproportionately dominated by shrubs (mostly sagebrush), and exotic grasses and forbs (ODFW 2006). These declines in site condition decreased the ability of soils to capture, store, and release water, causing sites to become more arid and less productive (Chambers 2008).

Courtesy Harney County Historical Museum

The Taylor Grazing Act of 1934 established federal management policy on public grazing lands to thwart serious long-term ecological damage throughout the west (ODFW 2006). Reseeding programs that focused on pasture grasses were initiated on Forest Reserves in the early 1900s (Monsen 2005). Areas that had already lost most of the native grasses and forbs were plowed or chained and seeded to crested wheatgrass (Agropyron desertorum, A. cristatum, and A. sibericum). By the 1970s, much of the sagebrush steppe was dominated by sagebrush with a crested wheatgrass understory (Chambers 2008).

Rangeland conditions have substantially improved in most areas since the early 1900s and grazing is managed sustainably in many parts of the Northwest High Desert. However, some areas, such as riparian habitats and arid areas of sagebrush and salt desert, are still negatively impacted by grazing and these sensitive areas have been found to recover slowly from grazing (ODFW 2006). Unfortunately, many of our native perennial grasses did not evolve under intense competition and are difficult to establish (Asay 2003). In highly degraded sagebrush habitat affected by grazing, invasive annuals and altered fire regimes, aggressive active management is needed to reestablish native perennials. Reseeding with native species and reducing fuel loads with fire and mechanical treatments are among the most commonly used restoration techniques (Shaw et al. 2005).