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

Abstract

The cultivation practices that were used in Europe and the eastern halfof North America were utilized in the initial settlement of the GreatPlains. Unfamiliarity with the climate of the Great Plains and Midwestand insufficient knowledge and technology to adapt crop productionsystems to the soils and climate lead to a major agriculture disasterwhich resulted in millions of hectares of land that needed to bere-seeded to grasses. Unrestricted grazing on public lands in theintermountain west resulted in severe rangeland degradation. Lack ofknowledge and technology for using native plants and some specificcharacteristics of native plants that made them difficult to useresulted in the use of crested wheatgrasses and smooth bromegrass whichhad characteristics that met specific revegetation and productionrequirements. Crested wheatgrass and smooth bromegrass plant materialswere from regions that were climatic analogs of the Great Plains andwere adapted. These two grasses literally preserved the remaining topsoil on millions of hectares of land. In the subsequent half-century,agronomist, geneticists, and rangeland scientists have learned how toestablish and manage native grasses such as switchgrass (Panicumvirgatum L.), big bluestem (Andropogon gerardii Vitman), indiangrass{[}Sorghastrum nutans (L.) Nash] and others so they are now availablefor use in revegetation. Although native grasses are available for usein the Great Plains and the Midwest of North America, crested wheatgrassand smooth bromegrass are now naturalized North American species andwill continue to be vital to the economy of the USA and Canada. Theirforage production patterns fits gaps in the forage production cycle forruminant livestock that cannot be adequately met by native species inregions where bromegrass and crested wheatgrasses are well adapted.