ABSTRACT
Temperate grasslands are generally dominated by graminoid vegetation and have less than 10 per cent cover of trees and shrubs. This chapter distinguishes primary and secondary temperate grasslands on the basis of the factors that conditioned their existence and maintain them. Primary grasslands occur where the establishment of woody plants is restricted by natural processes. Extensive primary grasslands whose existence is conditioned by the macroclimate represent zonal biomes. Some of the temperate grasslands in the Midwestern and eastern United States were created by anthropogenic clearing and grazing. In North America, the relative importance of natural factors and the cultural practices of Native Americans before European settlement are difficult to ascertain, though there is evidence that some grasslands were strongly shaped by cultural practices. Grasslands provide many ecosystem services, so their restoration can be profitable for humans. However, grassland restoration is also a moral challenge or obligation.
