Ventenata (Ventenata dubia) represents a significant threat throughout western Montana rangelands. Ventenata is found in sites infested with medusahead wildrye (Taeaniatherum caput-medusae) and cheatgrass (Bromus tectorum) forming a ventenata-medusahead-cheatgrass (VMC) annual invasive grass complex. Ventenata will eventually replace cheatgrass and medusahead, further reducing forage and degrading the site (Hironaka, 1994). The VMC complex follows invasional meltdown ecological theory, where one invasive species is replaced by another invasive species, transforming habitats, degrading ecosystems, and reducing biodiversity causing severe negative impacts that are exploited by another more damaging invasive (Simberloff, 1999).

For more information on ventenata dubia click the link to the Montana Weed Control Association web page.

Taeniatherum caput-medusae (Medusahead) is also an invasive winter annual with similar growth and life cycles to ventenata and bromus tectorum. Montana has similar moisture precipitation patterns as Medusahead’s native region of Eurasia. Medusahead has minimal forage value for wildlife and lifestock because of being high in silica. Ventenata is more widespread than medusahead and invading more land types including range, dry pasture, roadways, sub-irrigated and seasonally irrigated lands.

For more information on medusahead click the link to the Montana Weed Control Association web page.

Bromus tectorum (Cheatgrass) is another part of the VMC complex. Cheatgrass is widespread across the reservation. Cheatgrass provides seasonal grazing for livestock and wildlife, whereas ventenata and medusahead provide minimal to no forage value. Currently there are no strategies designed to contain VMC and restore productivity. We will test Esplanade (indazaflam) and Round-up (glysophate) herbicides and no-till seeding of native and introduced grasses suppressing VMC and restoring ecosystem functions.

For more information on cheatgrass click the link to the Montana Weed Control Association web page.