ABSTRACT
More than 40 percent of the world’s agricultural land is covered by grassland communities used for grazing livestock (Zimdahl, 1999). These complex plant communities are typically denoted as either rangelands or pastures, depending on the level of management input that is employed to obtain some productive output from them. Rangelands have been defined as seminatural ecosystems that are grazed with relatively little other management input, while at the other end of the management spectrum, intensively managed pastures may be planted down to improved species, irrigated, and fertilized. Grazing may also be highly regulated in pastures. For the purposes of this discussion, all grazed plant communities will be referred to as pastures, and an ability to manage these pastures in some way and the animals that graze them will be assumed.
