Mechanisms used to restore biodiversity

Land degradation has many causes ranging from population size and growth to weather changes and natural causes. According to a recent study, population pressure is one of the main causes of soil erosion, desertification, deterioration, and degradation of land, along with factors such as poverty, political instability, and education.

The increase in population numbers in especially developing countries increases the pressure on already limited resources such as by reducing food security and increasing the need for cultivation land to the point where the use of non-suitable and ecologically fragile areas is used.

Grazing is one of the heaviest land use practices. Its impact on land degradation is most visible in eastern and central South Africa along with the Bushveld region in Limpopo, where overgrazing is the main cause of desertification.

Desertification is when a semiarid or arid area is subjected to severe biological loss and the ability to be biologically productive due to stresses such as overgrazing.

Overgrazing does not just cause biological loss but can physically change the vegetation composition and structures, such as the ecological functions which include the soil absorption capacity, rate of decomposition of litter, and nutrient cycles.

Grazing pressures are not just from cattle but can be due to the overpopulated herbivores wildlife in the area as well, this can be due to a lack of natural predators or from the blockade of migration routes.

Woody encroachment is often observed in the Savanna biomes globally. Intense grazing enhances the ability of trees to grow better due to the lack of competition for water and space, however where grazing lawns are used and the establishment of tree seedlings is prevented in a way. Browsers, elephants, or gouts, can reduce the increase of the woody biomass seedling or population size.

In order to restore or rehabilitate the area to a standard that can support life, both for humans and animals, an investigation of the mechanisms used by farmers and landowners to restore degraded land is conducted.

The mechanisms investigated were: cattle hoof impact, chemical herbicides, bulldozing trees, tree cutting, fire, and grass planting.

Using a variety of mechanisms to aid in the rehabilitation or restoration of degraded land was the best and most effective course of action, to ensure fast and successful recovery of the degradable areas, however, the costs of each of these mechanisms were expensive.

• (This extract forms part of an honors research study conducted by Corlize van den Berg under the supervision of Ms. N Mmbadi at the University of South Africa.)