GRAZING AND PLANT PERFORMANCE

Grazing is more than just defoliation of plants. The impact of herbivory affects ecosystem structure and function, both above and below ground. Ultimately, effects of herbivory are expressed to varying degrees at many levels of the ecosystem. Herbivory has been shown to affect plant physiology, morphology, and genetics. Plants have evolved many ways to avoid or tolerate herbivory. Whether plants overcompensate, equally compensate, or undercompensate to herbivory depends on pre- and post-harvest conditions of the plants and their environment. To be important 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 like compensation is to have practical application for the manager, then meaningful effects must occur on time and spatial scales that the manager can respond to with available resources.