where groups of animals feed excessively from one area of land or pasture without letting the vegetation in that area fully recover. It is a phenomena that can be seen both in the natural world, but it is also seen within farming and livestock. It is commonly seen when the farmer or owner of the livestock has too many individuals feeding in one area¹. There are many negative effects to overgrazing for native species including soil erosion, land degradation and loss of valuable species.
The first and the most troublesome effect of overgrazing is soil erosion. If an area is allowed to be overgrazed, the vegetation is repeatedly being trampled, the native plants will be unable to grow and start to die. Additionally, after the ground has been walked on repeatedly by large livestock, the ground becomes more firm, making it harder for the native vegetation to grow in the compact soil. After the soil is bare, it is very easy for natural erosive processes such as wind or water to remove the top layer of soil¹.
Land degradation is a process that happens when no protective measures to address soil erosion are taken. The top layer of soil contains the most amount of nutrients and when this layer and the nutrients within are removed, it is very difficult to recover soil quality and amount of nutrients. This also makes it very difficult for native plants start to grow again. If land degradation process continues, it eventually leads to desertification¹.
The dust bowl of the 1930s in the United States was an example of the widespread negative effects overgrazing, soil erosion and land degradation can have to a landscape.
Loss of Valuable Species
Overgrazing also affects how native species are distributed in the environment and how they are able to regenerate. For example, after a pasture is overgrazed, the root system of the native plant is damaged which makes regrowth difficult and slow. It often leads to the spread of nonnative or invasive species¹. Then, it is even more difficult for the native species to recover. The loss of valuable species is true of native plants but can also cause a loss of native animal species, if an area that is overgrazed is part of an important food source or habitat for a native animal.
An example of the damaging effects of overgrazing of wild species can be seen in the Caledonian Forest in Scotland. This area has seen a limited regrowth of young trees in the forest over the past 150-200 years due to overgrazing of native herbivores like red deer and sheep. When the seedlings start to grow, they are eaten by these herbivores before they have a chance to grow. This problem has intensified due to the increasing deer population and lack of natural predators in the area to control the deer population³.
Overall, there are many negative effects of overgrazing for native species. While some of the ways to prevent overgrazing including proper animal management, better land management, and sustainable pasture practices¹, they are often not performed, even though these are important steps to take to preserve the quality of the land for future generations.