Technical Abstract: Rangeland ecosystems account for about half of the earth's land surface. They play an important role in providing forage for livestock and wildlife, and they serve as critical watershed areas. Many of the world's rangelands have been degraded by overgrazing, marginal crop production, mineral and energy extraction, recreation, and other human-caused disturbances. This degradation has led to invasion by exotic weeds and subsequent increases in fire frequency. This, in combination with uncertainties associated with global climatic change, has resulted in a critical need for plant materials to restore and revegetate rangeland ecosystems. Common-garden studies and DNA genotyping were used to describe genetic diversity in three rangeland legume species indigenous to rangeland ecosystems of the Great Basin Region of the western USA. Results of these studies are presented as three case studies that describe the data collection procedures, analysis, and interpretation used to identify population structures in each species. These data formed the basis for the identification of geographically based metapopulations in these three legume species that can be used to develop plant materials for commercial seed production.