PLANT DIVERSITY CHANGE IN GRASSLAND COMMUNITIES ALONG A GRAZING DISTURBANCE GRADIENT IN THE NORTHEAST CHINA TRANSECT
中国东北样带草地群落放牧干扰植物多样性的变化

Grazing disturbance is one of nain factors affecting change in plant diversity of grassland communities. The results of this study of nine major grassland communities along the grazing disturbance gradient in the Northeast China Transect showed that the Shannon index was the highest in moderate grazing or heavy grazing stages, changing as follows: Moderate grazing-Heavy grazing>Heavy grazing-Moderate grazing)>Light grazing>Over grazing. While species richness had a higher contribution to species diversity, compared with evenness, changes in evenness contributed most towards the rate of change in diversity than did changes in species richness. Life form diversity also manifested some obvious changes along the grazing disturbance gradient. The pattern of plant diversity of the steppe region in the Northeast China Transect was Meadow steppe > Typical steppe > Desert steppe > Alkaline meadow.