Original sentence: A major impact of desertification is biodiversity loss, and loss of productive capacity, such as the transition from grassland dominated by perennial grasses to one dominated by perennial shrubs.Desertification  is the degradation of land in arid, semi arid and dry sub-humid areas resulting from various factors including climatic variations, but primarily human activities.In the Madagascar central highland plateau, virtually ten percent of the entire country has been lost to desertification due to slash and burn agriculture by indigenous peoples.Modern desertification usually arises from the demands of increased populations that settle on the land in order to grow crops and graze animals
Edited sentence: Attempts to define or map areas have been sharply criticized.Desertification  is the degradation of land in arid, semi arid and dry sub-humid areas resulting from various factors including climatic variations and human activities.However, there has been major controversy over the definition of the term, as well as its causes.Modern desertification often arises from the demands of increased populations that settle on the land in order to grow crops and graze animals.What is usually less controversial is the fact of biodiversity loss, and loss of productive capacity, such as the transition from grassland dominated by perennial grasses to one dominated by perennial shrubs