Herbivore overgrazing results in benefits and consequences. Consequences include soil degradation, a decrease in plant density, and loss of biodiversity. Benefits include increased fitness, offset loss of biodiversity, and increased growth rates and seed production. The effects, either beneficial or detrimental, can also be determined by the herbivore. The paper Woodland loss and restoration in a savanna park: a 20-year experiment by Western and Maitumo looks at overgrazing of livestock, pathogens, climate, and elephant over browsing. In this paper we can see both the benefits and consequences of herbivore overgrazing.
In this study seedlings protected from elephants, but exposed to other large herbivores grew vigorously. Seedlings exposed to elephants in control plots showed no significant growth. It was determined that elephants were preventing regeneration. Therefore overgrazing by large herbivores (except elephants) increased fitness, growth rates, and seed production. However overgrazing by elephants decreased plant density and resulted in a loss of biodiversity.
For more information please consult the paper listed below and team 7 handouts and tackk board.
Western, D. & Maitumo, D. (2004). Woodland loss and restoration in a savanna park: a 20-year experiment. African Journal of Ecology, 42: 111-121