As a case study, the responses of Leymus chinensis steppe of Songnen plain in northeast of China to human being activity (light grazing, middle grazing, heavy grazing and overgrazing) were discussed based on the field observed data.

• 结果表明，随著放牧强度的增加，羊草草原的植被盖度和生物量随之降低，优势羊草群落将逐渐被盐生植物所替代，群落结构趋于简化，物种向旱生化和盐生化演替。