What is Cheatgrass? Cheatgrass (Bromus tectorum), is an invasive annual species. This species poses a significant ecological threat to the Southern Great Plains of Texas, particularly in the Rolling Plains Region. Cheatgrass will displace native grasses such as sideoats grama (Bouteloua curtipendula), blue grama (Bouteloua gracilis) and little bluestem (Schizachyrium scoparium). These dominant, perennial, native grasses are key to maintaining soil stability, biodiversity, and forage quality (D’Antonio & Vitousek, 1992; Chambers et al., 2014).
How does cheatgrass outcompete native grasses? Cheatgrass has an early germination and a rapid growth. Due to these two aspects, it outcompetes the native species for the limited resources available. Cheatgrass also completes its life cycle before native grasses begin to thrive and opportunistically monopolizes the water and nutrients in the soil (Bradford & Lauenroth, 2006). This process reduces overall biodiversity and quantity of high-quality forage available for livestock to graze.
Cheatgrass also dramatically alters the fire regime by increasing the frequency and intensity of wildfires. This is due to its dense and dry biomass that becomes rapidly available as fuel for fires. Cheatgrass is fire-adapted and can quickly regenerate after a fire.
Cheatgrass can also easily alter belowground soil dynamics. Native grasses play a role in preventing soil loss through their extensive root systems. Cheatgrass does not have extensive root systems, and can pose a significant risk of soil degradation making way for potential soil erosion losses.
What can ranchers in Texas do to minimize cheatgrass? Keeping bare ground to a minimum and maintaining effective management and restoration of perennial, native species helps prevent cheatgrass from dominating into a monoculture. Prioritizing residual forage bases following grazing is a must as native grass species are essential for maintaining the resilience of the Southern Great Plains landscape (Davies, 2011).
For more information, be sure to check out the Cheatgrass Invasions and data co-authored with USDA-NRCS Rangeland Management Specialist – Matthew Coffman.