Conifer Encroachment: Effects on Invasive Grasses
Conifer encroachment reduces perennial grasses and increases woody fuels, making conversion to weed dominance more likely following high-severity wildfire.
Key Science
- Resilience to disturbance and resistance to invasion declines as sagebrush grasslands transition to woodlands, especially on warmer and drier sites, emphasizing the importance of conifer management in the early phases of encroachment (Chambers et al. 2014, Roundy et al. 2014)
- Early phase conifer removal has been shown to improve sagebrush ecological integrity of degraded core sagebrush areas at landscape scales and deliver better outcomes than wildfire (Naugle et al. 2024, Smith et al. 2024)
- Invasive annual grasses also increase following conifer removal, so land managers should plan follow up weed control where appropriate. Risks of invasion depend primarily on site conditions like soil temperature, moisture, and existing perennial vegetation (Miller et al. 2014, Davies et al. 2019, Chambers et al. 2021)
Additional Resources
- Pinyon-Juniper Encroachment: Effects on Invasive Species
- A field guide for selecting the most appropriate treatment in sagebrush and pinon-juniper ecosystems in the Great Basin: Evaluating resilience to disturbance and resistance to invasive annual grasses, and predicting vegetation response
- Invasive Annual Grass Resources and Trainings - University of Wyoming’s Institute for Managing Annual Grasses Invading Natural Ecosystems (IMAGINE)
