How Does Overgrazing Affect Grassland Areas?

The term grazing refers to the way many herbivores eat. They feast on grasses and other vegetation in their habitat. Grazing is most commonly associated with raising livestock for food production, but free roaming herbivores also graze. While grazing is a normal, natural process, overgrazing can occur when too many livestock are kept in a pasture, when pastures are not rotated or even in the wild when overpopulation of native or invasive species leads to a food shortage.

Soil Erosion

• The biggest effect overgrazing has on grassland areas is soil erosion, which is the gradual wearing away of the soil. Soil erosion is actually a natural process that is very beneficial to the environment. However, when overgrazing and other environmentally destructive processes are involved, the erosion happens too quickly, which becomes a detriment to the environment. Erosion occurs when the grasses and plants are not there to hold the soil in place with their roots. Erosion also leads to poor soil quality, so that the grasses have more difficulty growing back.

Water Quality

• Water quality is also affected by overgrazing and the consequent soil erosion. Soil and other sediment "runs off" into nearby bodies of water due to the lack of vegetation to hold soil in place. This runoff causes changes to the water composition. While small changes can typically be buffered, the water is bombarded after overgrazing, which leads to an increase in nitrogen and phosphorus. High concentrations of nitrogen-containing compounds in water can lead to serious medical conditions, including cancer. The added phosphorus leads to eutrophication, which is often referred to as an algae bloom.

Loss of Biodiversity

• While healthy grazing encourages habitats for ground-nesting birds and smaller animals, overgrazing destroys the habitat, leading to decreased biodiversity in the area. The biodiversity of the plant species in the grassland area is also affected by overgrazing. If the animals are eating all of certain species of plants within the area, it opens up the door for other species of grasses to colonize the area. These grasses may or may not be desirable.

Animal Health

• Overgrazing of grassland areas leads to poorer animal health, regardless of whether the animals are livestock or wild. Animals attempting to forage on overgrazed land are forced to eat less nutritious grasses, which results in animals that are not as healthy. These animals may not have enough fat reserves to make it through the winter. Poor nutrition is also a factor in reproduction, which can result in reduced populations. While reduced populations of wild animals may help avoid overgrazing in the future, it would have a detrimental financial impact on livestock.