Establishing Big Sagebrush Seedlings on the Colorado Plateau Kari E. Veblen, Eric Thacker, Mark Larese-Casanova, Kyle Nehring, Utah State University, Department of Wildland Resources Mike Duniway, U.S. Geological Survey, Southwest Biological Science Center Colby Brungard, New Mexico State University, Department of Plant and Environmental Sciences
Background Big sagebrush (Artemisia tridentata) is a foundational rangeland species important to wildlife habitat across the western U.S. On the Colorado Plateau, sagebrush is important browse for ungulates, such as mule deer and pronghorn, which motivates a great deal of restoration effort. However, most scientific knowledge of big sagebrush comes from the Great Basin. We know much less about how to restore sagebrush on the Colorado Plateau, where soils and precipitation patterns are different and conditions are warmer and drier. Factors such as soil type and precipitation vary across rangeland landscapes, and these factors in turn affect restoration outcomes and ultimately mean that “one size fits all” management strategies are not effective across large, complex landscapes. We know from studies in the Great Basin that sagebrush seedling establishment is strongly influenced by soil surface moisture1,2 and soil physical properties like texture and depth.3,4 However, how soil texture and depth affect sagebrush establishment—and ultimately restoration efforts—on the Colorado Plateau is unknown. For example, finer (i.e., higher in clay content) soils hold more water. But under hot, dry conditions, soils with a coarser (i.e., sandier) surface layer can be advantageous because they are well drained and allow water to percolate deeper into the soils instead of being lost to surface evaporation.7 In the Colorado Plateau’s sandy soils, it may be that sandier, well-drained soils are only advantageous if they are also shallow enough (due to the presence of bedrock or other water- and root-restricting layers) to retain soil water in the root zone available for plant uptake.
Research Wyoming big sagebrush seedling establishment studies were conducted in San Juan County, Utah, on the Colorado Plateau (Figure 1). 1
Figure 1. Study Area (black box) Within the Colorado Plateau (gray), With Respect to the Broader Sagebrush Ecosystem (green) and Western U.S.