Overgrazing

Overgrazing occurs when plants are exposed to intensive grazing for extended periods of time, or without sufficient recovery periods. It can be caused by either livestock in poorly managed agricultural applications, game reserves, or nature reserves. It can also be caused by immobile, travel restricted populations of native or non-native wild animals. Overgrazing reduces the usefulness, productivity and biodiversity of the land and is one cause of desertification and erosion. Overgrazing is also seen as a cause of the spread of invasive species of non-native plants and of weeds. Degrading land, emissions from animal agriculture and reducing the biomass in a ecosystem contribute directly to climate change. between grazing events. Successful planned grazing strategies have been support in the American bison of the Great Plains, or migratory Wildebeests of the African savannas, or by holistic planned grazing. Overgrazing typically increases soil erosion. With continued overutilization of land for grazing, there is an increase in degradation. This leads to poor soil conditions that only xeric and early successional species can tolerate. Native plant grass species, both individual bunch grasses and in grasslands, are especially vulnerable. For example, excessive browsing by white-tailed deer can lead to the growth of less preferred species of grasses and ferns or non-native plant species that can potentially displace native, woody plants, decreasing the biodiversity. Common land Overgrazing is used as an example in the economic concept now known as the Tragedy of the Commons devised in a 1968 paper by Garrett Hardin. This cited the work of a Victorian economist who used as an example the over-grazing of common land. Hardin's example could only apply to unregulated use of land regarded as a common resource. Normally, rights of use of Common land in England and Wales were, and still are, closely regulated, and available only to "commoners".