Abstract: By using “space instead of time” approach, this paper studied the niche dynamics of plant populations and the changes of plant functional types along a successional series on zokor mounds. Twenty main plant species were chosen to analyze their niche breadth and overlap by using the Shannon and Pianka indices. The results showed that larger niche breadth was often accompanied with larger niche overlap, but some plant species with smaller niche breadth also had larger niche overlap. The niche overlap among plant species was generally large. With the succession, the annual or biennial forbs first decreased rapidly and then slowly increased but overall decreased, the perennial forbs decreased after an initial increase, while the perennial grasses increased linearly, reflecting that perennial grasses finally dominated the climax communities. The grassland quality index was used to analyze the vegetation cover on the mounds, and the results indicated that with the succession, the grassland quality index increased significantly.

Key words: Life history, Disturbance, Seed morphology, Vegetative reproduction, Soil seed bank