What is Sagebrush Steppe Anyways?
Updated: Sep 21, 2020
As you might have read once or twice by now, my thesis work is all centered on an ecosystem called sagebrush steppe (pronounced like a stair step). If you haven’t ever heard of it before, allow me to provide you with an overview of why these plant communities are uniquely awesome and important to preserve. Sagebrush steppe is often overlooked as a monotonous roadside sea of dull browns and pale greens but this perception is far from the truth! Diversity in the steppe can be quite high and can include everything from shrubs with edible berries, to sedges, to hemiparasitic plants, to pastel wildflowers, to elegantly long-awned grasses! In fact, if you take the time to look just a little closer, you will find that steppe communities team with life of many types and natures as organisms take full advantage of these arid-land oases of food and shade.
Several species depend on the steppe for winter forage, nesting, and raising young. Artemisia tridentata (big sagebrush), the star of the sagebrush steppe, peaks just above the snow line in winter, providing its evergreen leaves to ungulates like elk and pronghorn who would have nothing else to eat otherwise. Shrubs in the steppe also help to lock in soil moisture and nutrients from decaying plants that would otherwise be lost. The threatened greater sage-grouse is a strange and beautiful bird that can live only among high quality, mature stands of sagebrush with lush wildflower “understories” that are possible because of sagebrush’s effects on soil. Of course, animals aren’t the only individuals in the steppe that are threatened by its destruction. For example, in my steppe field sites there exists a lustrious rare wild hyacinth known as Triteleia grandiflora which can only be found in a few spots in Wyoming (mostly in the Grand Teton National Park)- giving it an imperiled designation by the Wyoming Natural Heritage Program.
Sagebrush communities sprawl throughout the western U.S. and can look quite different from region to region, each providing crucial habitat for various plants and animals. Steppes are distinguished from sagebrush shrublands based on their higher herbaceous (flowering plant) cover. There are several big sagebrush subspecies throughout Wyoming which differ very slightly in appearance but can taste distinctly different to browsing animals. The Wyoming big sagebrush species is more prominent in the warm, dry, low elevation parts of the state, while Mountain big sagebrush is found in the wet, cool, high elevation sites like those found in Grand Teton National Park. The Intermountain montane sagebrush steppe communities found in the park are characterized by a more equal share of shrubs, grasses, and wildflowers while drier basin sagebrush shrublands tend to have lower diversity and are mostly dominated by sagebrush. Even within Grand Teton National Park we can find a couple of community "subtypes" that are differentiated by the types and abundances of shrubs and grasses that co-occur with big sagebrush.
Unfortunately, despite the fact that sagebrush steppe covers a huge portion of the west including much of the Greater Yellowstone Ecosystem and Grand Teton National Park in particular (almost 25% of the park!), it has already been reduced to 50% of its original range by conversion or degradation. This means that while the steppe is one of the most widespread ecosystems in North America it is also one of the most altered. Oil and gas extraction and agricultural/ranching uses are major threats to the steppe and climate change has further increased the impact of these pressures. Observed and projected effects of climate change in the GYE include earlier snowmelt and reductions in annual snow pack which particularly threaten the sagebrush component of the steppe as these shrubs rely on winter precipitation to recharge available groundwater. Additionally, increased wildfire frequency can enhance invasion by non-native annual grasses like cheatgrass (Bromus tectorum) which create even more fuels and subsequently even more wildfires. Big sagebrush is not fire tolerant and can take decades to reach heights necessary to provide food and shelter for reliant wildlife. Additionally, when sagebrush is gone soils can dry out and lose the ability to support the diversity of wildflowers that used to be abundant.
Luckily, efforts to conserve and restore sagebrush steppe are growing strong throughout the west and the work ongoing at Grand Teton National Park is a major contribution. Grand Teton has already invested a decade into returning land farmed for hay by Mormons to stable, diverse sagebrush steppe communities. The park has furthered their commitment by partnering with our team here at the University of Wyoming in order to apply the best available (“cutting veg”) science to improve restoration success and climate resilience in the long term. The ultimate project goal is to restore a whopping 4,500 acres- what an amazing and hopeful effort to preserve a very important ecosystem which is iconic to the Teton region! I am honored and excited to be a part of this impactful work and I look forward to seeing and sharing the results as we continue on this scientific journey.
"As far as the eye could reach nothing could be seen but the blue sky and a wilderness of wild sage. The sun was excessively hot and there was not a breath of air in motion. A profound stillness hovered over the landscape and we seemed to travel in a world of sunshine, silence and sage." Reuben Shaw, Across the Plains in Forty-Nine (1948)
Learn more about sagebrush plant communities here.
-Häslein (aka FBK, aka Sienna)