Review on Evolution Mechanisms of Grassland Ecosystem

In this paper,the researches at home and abroad on the evolution mechanisms of grassland ecosystem were reviewed.The domestic researchers emphasized that natural factors and human factors were the two driving factors of grassland’s degradation and desertification,and population pressure and irrational human activities were the main driving factors.In contrast,foreign researches were more systemic and thorough.The grassland ecology paradigm developed from equilibrium theory which emphasized biological factors as the main factors of grassland degradation to nonequilibrium theory that emphasized environmental strong fluctuation controlled grassland ecosystem evolution.And the global driving factors’list of grassland ecosystem evolution included population,economic,social,political,science and technology,culture and religion,as well as physical,biological,chemical and other factors had been accordantly generated.