the people of the region were traditionally Nomadic. They moved following the rain and pasture- land. Wealth was defined by animal ownership by the tribes of the Sahel. As the number of cattle and goats increased so did the competition for grazing land. They allowed the animals to graze the land more than it could sustain. Young trees were also grazed. Herders also moved animals onto marginal grazing land until there was little or no vegetation remaining.
Wells were sunk to provide water for all the animals. This made herders remain longer in the one area applying more pressure on the land. The wells used up all the ground water causing the water tables to fall. Eventually the wells dried up along with the land around it.
As the human population increased farming methods changed, Nomadic herding was replaced with a more settled style of herding. Farmers began to fence in land and work it more intensely. Leading to soils being overused an d exhausted. Soils began to lose structure an minerals. Vegetation was lost due to the large numbers of animals grazing and trampling the land. It was also unable to grow back because the soil was now drained of all its nutrients. This in turn has a knock on effect, when the vegetative cover is lost it leaves the soil exposed to erosion by wind and heat. It leaves an easy job for heavy rain to wash away the topsoil.
The population of the region grew rapidly and this led to an increased demand in food. Grazing became...