THE EFFECT OF HILL-BUILDING ACTIVITIES OF ANTS ON THE SPECIES DIVERSITY OF PLANT COMMUNITIES IN SONGNEN GRASSLAND
蚂蚁筑丘活动对松嫩草地植物群落多样性的影响

The activities of ants are a major biotic disturbance factor in a grassland ecosystem. In present study, the plant species composition, quantitative characters of dominant plant species and diversity variation of community on the ant-hills of two dominant species-Lasius alienus (Foerster) and L. flavus (Fabricius) were analyzed and compared to discuss the roles of hill-building activities of ants in the grassland ecosystem. The results were as follows: 1) the plants on ant-hills could be classified into Aneurolepidium chinense group, Kalimeris group and Setaris group, suggesting that the species composition of vegetation on ant-hills was significantly different from that of controls; 2) the biodiversity of vegetation on L. alienus ant-hills in all plant communities but the A. chinense communities was less than that of controls, and the total above ground biomass of plants was more than that of controls in those four communities; 3) the biodiversity of plants on L. flavus ant-hills was less than that of controls in A. chinense-Kalimeris integrifolia communities and A. chinense-Phragmites communis communities, but the biodiversity in A. chinense-Chloris virgata communities was more than that of controls;and in A. chinense-K. integrifolia communities and A. chinense communities, the total aboveground biomass on L. flavus was more than that of controls, but in A. chinense-C. virgata communities and A. chinense-P. communis communities. The cause might be the improvement of the soil physical-chemical properties on ant-hills and the limited seed flows from the communities around the ant-hills.