4 Humans, Climate, and Plants: the Migration of Crested Wheatgrass and Smooth Bromegrass to the Great Plains of North America

The cultivation practices that were used in Europe and the eastern half of North America were utilized in the initial settlement of the Great Plains. Unfamiliarity with the climate of the Great Plains and Midwest and insufficient knowledge and technology to adapt crop production systems to the soils and climate lead to a major agriculture disaster which resulted in millions of hectares of land that needed to be re-seeded to grasses. Unrestricted grazing on public lands in the intermountain west resulted in severe rangeland degradation. Lack of knowledge and technology for using native plants and some specific characteristics of native plants that made them difficult to use resulted in the use of crested wheatgrasses and smooth bromegrass which had characteristics that met specific revegetation and production requirements. Crested wheatgrass and smooth bromegrass plant materials were from regions that were climatic analogs of the Great Plains and were adapted. These two grasses literally preserved the remaining top soil on millions of hectares of land. In the subsequent half-century, agronomist, geneticists, and rangeland scientists have learned how to establish and manage native grasses such as switchgrass (Panicum virgatum L.), big bluestem (Andropogon gerardii Vitman), indiangrass [Sorghastrum nutans (L.) Nash] and others so they are now available for use in revegetation. Although native grasses are available for use in the Great Plains and the Midwest of North America, crested wheatgrass and smooth bromegrass are now naturalized North American species and will continue to be vital to the economy of the USA and Canada. Their forage production patterns fits gaps in the forage production cycle for ruminant livestock that cannot be adequately met by native species in regions where bromegrass and crested wheatgrasses are well adapted