NEET BIOLOGY

Detailed explanation-1: -With the exception of irrigation-induced land degradation, desertification usually starts with the removal of vegetation cover by humans or livestock. Overgrazing and excessive fuelwood collection destroy the protective layer of plants, exposing the top layer soil to wind and water erosion.

Detailed explanation-2: -’Climatic variations’ and ‘Human activities’ can be regarded as the two main causes of desertification. removal of the natural vegetation coverby taking too much fuel wood, agricultural activities in the vulnerable ecosystems of arid and semi-arid areas, which are thus strained beyond their capacity.

Detailed explanation-3: -Human activities that contribute to desertification include the expansion and intensive use of agricultural lands, poor irrigation practices, deforestation, and overgrazing. These unsustainable land uses place enormous pressure on the land by altering its soil chemistry and hydrology.

Detailed explanation-4: -The definition of overgrazing is “excessive and continuous grazing, which causes damage to grass or rangelands.” The key word of that statement being “continuous, ” as overgrazing is determined by the amount of time that livestock are allowed to graze, not by the actual amount of forage that they utilize.

Detailed explanation-5: -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.