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North East Wyoming Invasive Grass Working Group (NEWIGWG)

Northeast Wyoming Invasive Grass Working Group (NEWIGWG)

Who are we?

NEWIGWG consists of multiple partners from local, state, and national organizations working together to reduce the impacts of these emerging threats to rangeland ecosystems and is supported from various sources.

  • Sheridan County Weed and Pest

  • University of Wyoming Agricultural Experiment Station

  • University of Wyoming Extension

  • Johnson County Weed and Pest

  • Campbell County Weed and Pest

  • Sheridan County Conservation District

  • Clear Creek Conservation District

  • Campbell County Conservation District


  • USFS

  • NRCS

  • BLM

  • Wyoming Military Department

  • The Nature Conservancy

  • American Bird Conservancy

  • Sheridan College

  • Wyoming Office of State Lands and Investments

  • Several private landowners. 


Why are Ventenata & Medusahead a problem?


This is the first time these species have been found in Wyoming and the Great Plains eco-region. The Great Plains eco-region is a high plateau of grasslands that extend from Canada down to Mexico. It has an area of approximately 1,125,000 square miles which is equivalent to one-third of the United States. This eco-region’s hot dry summers and cold wet winters are similar to the area where these grasses are native. As you can see, the potential for spread is alarming. Here, in their non-native land, they strangle local flora, promote dangerous wildfires, diminish diversity, and reduce wildlife habitat. These annual grasses out-compete native vegetation because they germinate early in the fall, overwinter as a seedling, and are the first things to commence growth in the spring, depleting soil nutrients and moisture. They are far more invasive than Cheatgrass and rapidly change native landscapes. They have the ability to reduce grazing capacity by 70%. This not only affects livestock but a wide range of wildlife, with particularly strong impacts on sagebrush grassland communities. Wyoming, having the most sagebrush of any state at 43 million acres, is a stronghold for Greater Sage-grouse that we must not lose.


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Immediately following their discovery, the Wyoming Cheatgrass Task Force met to discuss an Early-Detection-Rapid-Response (EDRR) program specifically for Medusahead and Ventenata. Based on recommendations from the Task Force, local partners formed the North East Wyoming Invasive Grasses Working Group (NEWIGWG) with a goal of reducing, containing, or eradicating Medusahead and Ventenata from northeast Wyoming. Primary objectives for the group are to: 1) clearly understand distribution and potential for spread of the target species, 2) develop and implement landscape-scale management strategies, 3) facilitate data sharing to enhance management, and 4) increase awareness around Medusahead and Ventenata with land managers and communities.

Over the last two years we have:

  • Developed and distributed written fact sheets and identification guides to more than 3000 contacts

  • Held local landowner ‘town hall’ meetings to share information about medusahead and ventenata

  • Gave over 100 educational presentations ranging from Weed and Pest Fall Conference to Wyoming Mining Natural Resources Foundation to neighboring states weed meetings to Western Weed Coordinating Committee - to name a few.

  • Hosted 2 annual field tours for over 100 participants from around the nation; media coverage included.

  • Provided boot brush stations and signs to over 20 locations and developed and distributed the Wyoming Invasive Grass Quick Reference Guide.

  • Surveyed 42,600 Acres

  • Chemically treated 9,695 Acres

  • And invested $445,694.24 in the fight against these invasives                        


Next Steps

NEWIGWG partners are currently implementing innovative methods to predict areas with high likelihood of invasion by coupling vector-pathway analysis with estimated habitat suitability to improve efficiency and effectiveness of survey efforts on the ground and potentially with unmanned aerial systems (drones). The current treatment strategy is to use herbicides over multiple years (as indicated by vegetation monitoring) to deplete the seed bank in an attempt to eradicate Medusahead. Ventenata efforts will largely focus on defining its distribution boundaries, then prioritize areas for treatment once its distribution is better documented. Local priorities for treatment will be considered based on local needs, impacts to livestock forage, and risk of fire to migration corridors, infrastructure and wildlife habitat. 



As more knowledge was gained regarding species distribution, NEWIGWG members discussed possible approaches to their management. Total gross acres of Ventenata distribution (as determined by connecting all confirmed locations as an outer boundary) approached 2 million acres in December 2017, although net infested acreage is estimated to be dramatically less than this. Known Medusahead infested acreage is less than 6,000 acres, so NEWIGWG decided to target its eradication from the region. This approach may change is additional populations are reported that significantly increase infested acreage. Incoming questions, sightings reports, and requests for information steadily increases - providing a clear indication that outreach and awareness are increasing. 

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