Prairies were one of the first ecosystems to receive restoration and rehabilitation attention in North America because of large-scale eradication in the eastern part of their range and widespread overgrazing and drought effects in the western part of their range. The legacy of this east-west difference is divergent approaches and goals of prairie restorations in different portions of the continent. Whereas eastern tallgrass prairie restorations have focused largely on reconstructing communities from bare dirt (restoration for biodiversity's sake), rehabilitations in the central and western mixed- and shortgrass prairies have focused largely on restoring function (soil retention and production for cattle grazing) in degraded but still existing systems. In the latter, diverse native communities were often replaced by low-diversity, non-native communities.  Recently, differences between the regions have decreased. In the east, ecosystem services (such as wildlife habitat, biofuels, and carbon sequestration) have received more emphasis. In the west, greater emphasis has been placed on restoring the diversity of native prairie communities, in part to combat the unintended consequences of past function-focused rehabilitations. The biodiversity-ecosystem functioning (BEF) perspective provides a useful framework for uniting these different approaches and emphases, and much of the empirical evidence supporting BEF theory comes from grasslands. The current balance of evidence supports the notion that, on average, greater plant diversity leads to greater plant biomass production and nutrient retention, but low-diversity communities with a few “high-performers” can achieve similar levels of functioning. On the other hand, a side-effect of rehabilitation practices aimed at providing function can be biodiversity protection.