Cheatgrass (Bromus Tectorum L.)‐‐An Ecologic Intruder in Southern Idaho

Seed Bank Depletion: The Key to Long-Term Downy Brome ( Bromus tectorum L.) Management

“…Its successful expansion in the western U.S. ultimately translated into downy brome providing much of the spring-utilized forage in the Pacific Northwest and the Intermountain regions by the late 1940s (Hull and Pechanec 1947). During this period in Idaho, for example, downy brome comprised up to 95% of the vegetation on about 3.9 million acres; was the principal vegetation on another 1.9 million acres; and provided 25% of the vegetation on an additional 9.9 to 14.8 million acres (Stewart and Hull 1949).…”

“…steppe up into the ponderosa pine (Pinus ponderosa) and Douglas fir (Pseudotsuga menziesii) zones (Hull and Pechanec 1947). In 1949 (Stewart and Hull 1949) and 1966 (Beatley 1966) downy brome was only a very minor member of the black greasewood-shadscale (Sarcobatus vermiculatus-Atriplex confertifolia) and salt desert shrub associations. Currently, downy brome is common in these plant communities (Brown 1971;Hunter 1991;West 1988;West and Ibrahim 1968;Young et al 1987;Young 2000).…”

“…Mountain big sagebrush communities are susceptible to downy brome invasion on warm exposures (south and southwest aspects). Downy brome is adapted to extreme drought and when growing under such conditions, it produces much smaller plants that still set seed to produce another generation and perpetuate its presence (Stewart and Hull 1949).…”

“…In eastern Idaho, downy brome is most abundant between 2,000 and 6,000 foot elevations but has been found up to 9,000 in that state (Stewart and Hull 1949). Downy brome has been found growing at or above 13,100 ft in the United States (Hunter 1991).…”

“…Downy brome has very fine leaves and shoots, accumulates fine litter, dries completely in early summer, and provides a highly flammable, fine and often continuous fuel (Billings 1952;Stewart and Hull 1949;Young 1989). Downy brome changed the historic fire frequency in the Great Basin from once every 70 to 100 years to once every 3 to 5 years (Knapp 1966;Whisenant 1990).…”