Bromus tectorum

It now is present in most of Europe, southern Russia, Japan, South Africa, Australia, New Zealand, Iceland, Greenland, North America and western Central Asia.

[3] It has become a dominant species in the Intermountain West and parts of Canada, and displays especially invasive behavior in the sagebrush steppe ecosystems where it has been listed as noxious weed.

[4] The reduction of native plants and the increased fire frequency caused by B. tectorum prompted the United States Fish and Wildlife Service (USFWS) to examine if the greater sage-grouse needed to be listed as a threatened or endangered species due to habitat destruction.

Research has shown that ecosystems with a healthy biological soil crust and native plant community will be resistant to B. tectorum invasion.

[2] Bromus tectorum is a winter annual grass native to Eurasia usually germinating in autumn, overwintering as a seedling, then flowering in the spring or early summer.

[10] The seeds maintain high viability (ability to germinate under optimal conditions) in dry storage, lasting over 11 years.

[16] Bromus tectorum has been introduced to southern Russia, west central Asia, North America, Japan, South Africa, Australia, New Zealand, Iceland, and Greenland.

[18] In Canada B. tectorum has been identified as an invasive weed in all provinces, and is extremely prevalent in Alberta and British Columbia .

Intensive sheep browsing of B. tectorum in early spring has been used as a fire fuels reduction strategy in the hills adjacent to Carson City, Nevada.

[20] Because of rangeland fires and the invasion of Bromus tectorum, in 2010 the United States Fish and Wildlife Service (USFWS) considered the possibility of extending the protections of the Endangered Species Act to the greater sage-grouse.

Since the review of the status of the greater sage-grouse by the USFWS in 2010 and the implementation Secretarial Order 3336 in 2015 the bulk of the research focusing on B. tectorum ecology and control has been completed.

Bromus tectorum has demonstrated a quantitative and qualitative response to recent and near-term changes in the concentration of atmospheric carbon dioxide.

[22] On the qualitative side, rising carbon dioxide decreased the digestibility and potential decomposition of B. tectorum.

[22] Ongoing increases in atmospheric carbon dioxide may contribute significantly to B. tectorum productivity and fuel load with subsequent effects on wildfire frequency and intensity.

[22][23] Bromus tectorum has been shown to benefit from endophytic colonization by morels (Morchella sextelata, M. snyderi) in western North America.

[26] A. cristatum is much easier to establish than the native perennials and has been shown to be a strong competitor of Bromus tectorum.

When using herbicides to suppress winter annual grasses the two most important factors that influence success are application timing and residual soil activity.

To be most effective post-emergence application needs to be done as late in the spring as possible to ensure that the herbicide treatment hits the majority of the B. tectorum population.

Imazapic is preferred because it can be applied both pre and post-emergence, is approved for rangeland use, and has residual soil activity that allows for one to two year control.

[31] The goal of a prescribed burn in a B. tectorum invaded area is to remove the highly flammable plant litter in a controlled manner.

[33] In some cases, the existence of adjacent morchella can trigger mutual relationships like increased fiber and, by extension, fuels that nurture the return of cheatgrass.

[33] Similarly, when densely packed conifers begin infilling sagebrush communities the understory perennial vegetation is reduced; when these areas are prescribed burned the succession is dominated by B. tectorum in favor of taller grasses, making burns situationally inferior.

In years of high precipitation, B. tectorum recruitment and biomass will increase and may render the treatment ineffective.

In arid regions BSCs colonize the spaces between plants, increase the biodiversity of the area, are often the dominant cover, and are vital in ecosystem function.

[36][5]  A decline in the health of the BSC community serves as an early warning indicator for Bromus tectorum invasion.

Bromus tectorum has a shallow, spreading root system, which makes it much more efficient at absorbing moisture from light precipitation episodes and disrupts nutrient cycling.

Studies have identified Poa secunda, Pseudoroegneria spicata, and Achnatherum thurberianum as key grasses for B. tectorum resistance.

A sagebrush ecosystem in southern Idaho after Bromus tectorum has established
Cheat grass in Elko, Nevada
Invasive Bromus tectorum on Spruce Mountain, Nevada