More Menace Than Cheatgrass?!
The following article is by Bebe Crouse, Communications Director for The Nature Conservancy in Montana and Wyoming, with contributions from the Intermountain West Joint Venture.
“It’s like a horror film!”
That’s the way The Nature Conservancy’s northeast Wyoming program director Carli Kierstead describes the rapid spread of two invasive annual grasses. What started as a few isolated patches of ventenata and medusahead is becoming a serious problem, with real economic consequences for Wyoming agriculture.
Ventenata, the bigger bad guy of the two, has been detected in multiple counties, expanding its reach in the Northern Great Plains of northeast Wyoming. The less widespread medusahead has also expanded its extent, but it’s still more localized to Sheridan County. These two species are actively germinating into new areas every year, but the number of acres detected is also a testament to increased awareness and better recognition and identification by landowners. The grasses are especially problematic for ranchers who find them not just in pasture, but in their hayfields as well. Their low, wiry growth and metallic taste cause livestock to avoid eating them. Even if they ate it, the high silica content and sparse leaves mean that the plants have little nutritional value.
Ventenata (left) and medusahead (right) grasses. Photo by Gary Stone.
“Ventenata and medusahead have proven to be even worse than cheatgrass,” Kierstead said. “These are the types of invasives that can change a landscape in irreparable ways. Ventenata is uniquely adept at outcompeting native grasses by stealing soil moisture in the early spring and creating thick ground cover in the fall. Both species present increased fire risk as well.”
Sheridan Weed and Pest specialist Luke Sander leads a group in Sheridan, WY as they observe the impacts of invasive grasses on private lands. Ventenata, bulbous bluegrass and and sulfur ciquefoil are seen in this photo. Photo by Jennifer Strickland, U.S. Fish and Wildlife Service.
The well-equipped invaders emerge earlier in the spring than natives, which helps their rapid spread. Ventenata also hosts a fungus that can infect and harm native species. They can thrive in wet or dry conditions, and their seeds are viable for three to five years. So even if standing plants are killed, the patch will have to be treated for years to control regrowth.
A few years ago, the negative economic impact of Ventenata was estimated at $22 million in northern Idaho and eastern Washington alone. And the grasses are making headway in Wyoming, with the potential to cause even more economic damage than cheatgrass.
With relatively new invasives like these, it can be a tough balancing act between timely action and gathering information. There is still time to make an impact, but the infestations are already serious at the landscape level. TNC Wyoming and partners of the Northeast Wyoming Invasive Grasses Working Group (NEWIGWG) are committed to ongoing research and knowledge gathering that parallels active management.
Pictured here is a boot-brush station. Photo by Slade Franklin, Weed and Pest Coordinator, Wyoming Department of Agriculture.
Kierstead said TNC has teamed up with the University of Wyoming Research and Extension Center to study two important management questions:
1) Which mode of data collection (horseback, drone, flight, or remote sensing surveying) is most efficient and effective for detection and monitoring of these specific species?
“Ultimately, we hope to evaluate the overall ability of remote sensing platforms to detect species of interest like medusahead and ventenata, and expand the ability to manage them at landscape scales,” she said.
2) How effective are the boot-brush stations as outreach and education platforms in northeast Wyoming? The social side to invasives management cannot be diminished. Any sustained success with the containment of these two species will be highly dependent on continuing to educate land managers, landowners, and the public.
“We don’t have time to hesitate,” Kierstead said.