Invasive Species
Webinar recording.
Disturbance events, such as overgrazing and the catastrophic fires, in our shrub steppe landscape can kick-start a negative feedback loop with invasion of noxious weeds. These invasive species can have a direct effect on services and ecological benefits provided by the shrug steppe landscape. Learn what we can do to minimize the spread of invasive plant species and how native seeds and grasses can be used to restore this brittle system.
Invasive annual grasses threaten millions of acres of sagebrush rangelands across the west. This two day workshop hosted by the Harney County Wildfire Collaborative and Oregon SageCon Partnership will explore the barriers and opportunities for addressing invasive annual grasses in Oregon and beyond the state. In this workshop some of the most pressing issues related to invasive annual grass management will be discussed, including the connection between invasive annual grasses and wildfire and what can be done to better address this threat.
VIRTUAL Workshop Dates & Agenda
Monday, December 14, 12:30-4:30pm: Defend the Core—Keeping the Good, Good
- Hard truths of invasive annual grasses
- Stopping the Spread
- Supersizing Suppression Success
- Reducing Wildfire Risk
- Ratcheting Up Resiliency
Tuesday, December 15, 8:30am-12:30pm: Grow the Core—Restoring At-Risk and Converted Lands
- Managing Invasive Annual Grasses
- Innovative Restoration
- Prioritizing Limited Resources & Sustaining Long-term Investment
- Where Do We Go From Here
View the document.
The toolkit is comprised of three elements:
- A roadmap for invasive grass management in the West, with new best management practices for the identification, protection, and expansion of “core” areas – regions with relatively low, or no, annual grass invasion;
- Case studies highlighting the application of these practices in Idaho and Wyoming; and
- A new geospatial data layer (which uses analytical tools to compile existing federal data) to help state and local managers assess invasive annual grasses within their jurisdictions, while also offering opportunities to identify new cross-boundary collaborative projects.
View report.
This Gap Report Update is the latest addition to the list of valuable products of the Working Group designed to help identify the challenges (gaps) and offer ideas to address those challenges. The Gap Report Update has something for every level, public and private, to consider helping address the fire and invasive threat. It is our hope that the leaders of the various state and federal agencies will review the recommendations in the report and determine if there are things they can affect directly to address the gaps. It took a multi-agency, multi-discipline Working Group to identify the problems and provide possible solutions to these conservation and management challenges, it will certainly take a broad-based coalition of agencies, and public and private groups working together to ensure a healthy Sagebrush Biome is available for generations to come.
View Part 1 (2:12) and Part II (2:08) recordings of this symposium.
This special half-day webinar symposium provides an in-depth review of three invasive grasses (cheatgrass, medusahead, ventenata) in the Western US.
View brief.
The Western Governors’ Association (WGA) has addressed this need by surveying invasive species coordinators in WGA member states and territories Top 50 Invasive Species in the West to develop the “Top 50 Invasive Species in the West.” The compilation of terrestrial and aquatic invasive species includes highly-publicized examples such as cheatgrass, Quagga Mussels, tamarisk and the Emerald Ash Borer. The list also encompasses less well known, but still impactful, examples such as leafy spurge, Red shiner, Russian knapweed, and Golden algae.
View article.
Though widely distributed throughout the study region, ventenata only appeared in 45% of the 225 plots, and foliar cover was typically less than 50%. It was primarily found in ephemerally wet microhabitats. Species richness and the Shannon diversity index were lowest in plots with high V. dubia cover. Nonmetric multidimensional scaling analysis revealed that ventenata and medusahead were closely associated. Furthermore, chi-square indicator analysis showed that T. caput-medusae was more prevalent, while mountain big sagebrush was less prevalent, in plots containing ventenata. Abiotic factors that explained variation in ventenata abundance included rock cover, soil depth, and a north/south aspect. Higher ventenata cover also correlated with higher clay content and lower phosphorus and potassium concentrations in the soil. We suggest that at this point, detection survey efforts to locate incipient infestations of ventenata in sagebrush steppe communities should focus on moist areas and sites susceptible to invasion by medusahead.
Access article.
USGS scientists Lea Condon and David Pyke tested the idea that biotic communities mediate the effects of disturbances such as fire and grazing on site resistance by using structural equation modeling to test relationships between disturbance events, the biotic community, and resistance to cheatgrass invasion. Increased site resistance following fire was associated with higher bunchgrass cover and recovery of bunchgrasses and mosses with time since fire. Fire reduced near-term site resistance to cheatgrass on actively grazed rangelands, and evidence of grazing was more pronounced on burned sites and was positively correlated with cheatgrass cover. Independent of fire, grazing impacts resulted in reduced site resistance to cheatgrass, suggesting that grazing management that enhances plant and biocrust communities will also enhance site resistance.
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This report found that treating low infestations across all three levels of forage production yields a financial gain, ranging from 21 cents to $4.94 per acre. However, treating highly infested areas showed a financial loss of $3.76 to $5.43 per acre, despite the level of forage production. Moderate infestations showed a financial gain with treatment only on sites producing 1,000 or 1,500 pounds per acre of forage.
View brief.
Cheatgrass is now found in at least 49 states, although it’s mainly a problem in the semi-arid Great Basin — which stretches across portions of Utah, Nevada, Idaho, Oregon, and California — since its adapted to thrive in areas with wet winters and hot, dry summers. People are now used to seeing cheatgrass-dominated landscapes, but it’s not what we should see.