Merits of native and introduced Triticeae grasses on semiarid rangelands

Experiments were conducted on four semiarid range sites to compare stand establishment, productivity, and persistence of several introduced perennial Triticeae grasses with that of their native counterparts. On Intermountain sites with severe water limitations (< 300 mm), native grasses were more difficult to establish, less productive, and less persistent than the introduced grasses. Stands of native grasses declined most rapidly under defoliation. At locations where moisture conditions were more favorable, particularly where more summer precipitation occurred, native Triticeae grasses established and persisted relatively well compared with the introduced entries. Although difficult to establish, stands of the rhizomatous native, western wheatgrass [Pascopyrum smithii (Rydb.) A. Löve] in creased during the seasons after establishment. Choice of plant materials to be used in range seeding programs should be based on objective criteria. To do otherwise will perpetuate degradation of soil resources, especially on sites that are dominated by weedy annual species such as cheatgrass (Bromus tectorum) and medusahead rye (Taeniatherum asperum). It is proposed that adapted introduced grasses be equally considered along with native grasses as a component of seed mixtures on environmentally harsh sites that have been burned, infested with competitive weedy species, or otherwise degraded. Key words: Grass breeding, revegetation, introduced grasses, Triticeae, cheatgrass, seedling vigor, plant persistence