GRAZING AND PLANT PERFORMANCE

Grazing is more than just defoliation of plants. The impact of herbivo ry affects ecosystem structure and function, both above and below grou nd. Ultimately, effects of herbivory are expressed to varying degrees at many levels of the ecosystem. Herbivory has been shown to affect pl ant physiology, morphology, and genetics. Plants have evolved many way s to avoid or tolerate herbivory. Whether plants overcompensate, equal ly compensate, or undercompensate to herbivory depends on pre- and pos t-harvest conditions of the plants and their environment. To be import ant to the manager, the magnitude of compensation must be greater than the inherent ''noise'' in the system. Natural resources managers use scientific information about herbivory to reduce ambiguity in decision -making in an environment of uncertainty. If an ecological response li ke compensation is to have practical application for the manager, then meaningful effects must occur on time and spatial scales that the man ager can respond to with available resources.