Ecological studies of Bromus tectorum and other annual bromegrasses

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Bromus tectorum is the most widespread and successful of the annual bromes introduced from Eurasia in many of the semi-arid parts of the western United States, particularly in the Columbia Basin and much of the Great Basin. Millions of acres where the native vegetation has been severely disturbed by grazing, fire, or cultivation are now dominated by this grass. It is so aggressive that in many places perennial grasses replace it very slowly through natural processes. Similarly, the success of efforts to reseed perennial grasses on range land dominated by Bromus tectorum is often in proportion to the degree of elimination of the Bromus. To enable such reseeding research to proceed efficiently, a knowledge of the root systems, germination requirements, and other ecological characteristics of B. tectorum was needed, but most research pertained to management of range land on which it occurred. Over 400 experimental plantings were made at the Lewiston (Idaho) Study Area and even more at the Pullman (Washington) Study Area—in addition to laboratory and greenhouse studies and many field observations of the annual bromegrasses occurring in Washington, Oregon, Idaho and Montana—to carry out ecological studies, primarily of B. tectorum and secondarily of 9 other species of introduced, Eurasian annual bromes. Summaries of findings from these Bromus plantings and studies are included here regarding genetic variation, habitats, phenology of species, winter injury, the roots, effects of nitrogen fertilizer, soil moisture, flower initiation, anthesis, effect of clipping, incidence of smut, shoot and seed production, dissemination of florets by wind, germination, longevity of seeds in the field, effect of burial depth on emergence, effect of burial times and depth on seeds, effect of dessication on seedlings, the beginning of viability, and length of viability in storage.

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ELECTRONIC FILE - Ecology