Effect of Water Redistribution and Large Bare Patch on Desertification

An agent-based model is developed to investigate the effect of water redistribution and the large bare patch (LBP) rule on desertification. Water redistribution of the focal cell refers to infiltration process determined by its neighbor cell´s state. The LBP rule is used to describe the phenomenon that more water will evaporate when many bare cells aggregate into a lager bare patch. Our results of simulation show that desertification will appear in the system with water redistribution and LBP rule, while in the system without these rules, desertification will not present with the same settings. Several features of desertification are revealed. Desertification occurs in a catastrophic way and there is a threshold of grazed density. Furthermore, the formation of LBP accelerates the process of desertification remarkably.