| Distribution of ant mounds are common in the alpine meadow of the Qinghai-Tibet Plateau.Ant mounds lead to the heterogeneity of the ant mounds and their adjacent areas by affecting the plant community structure and soil seed bank species composition,then cause the evolution of grassland vegetation.In this study,the plant community characteristics(height,coverage,biomass,diversity and feeding value),species composition(density,species,etc.)and species similarity relationship of soil seed bank were quantitatively analyzed in the alpine meadow of three sample sites(Menyuan and Maqin in Qinghai province and Tianzhu in Gansu Province)on the Qinghai-Tibet Plateau.Clarify whether it is common for ants to build mounds to reduce plant species diversity in alpine meadow?Does it have a Matthew effect on the dominant species?The main results are as follows:Ant mound-building reduced the frequency of Legumes,Compositae,Gentiaceae and Ranunculaceae at the edge of the ant-mound,and promoted the succession to grass and sedge community,increased the height and biomass,decreased the number of species and Shannon-Wiener diversity index,and increased the Pielou index.In Menyuan and Maqin,the important values of Poa pratensis at the edge of the ant-mound were 1.65 and 4.43 times of those in the control,respectively.In Tianzhu,the important values of Kobresia capillifolia and Stipa krylovii were 1.30 times and1.44 times of the control,respectively.Ant mound-building significantly increased the aboveground biomass of grasses and sedges and the proportion of superior forage,and changed the plant growth form and life form.There was a significant linear negative correlation between the number of plant species and aboveground biomass.The density of 0-10cm seed bank above,below,the edge of the ant-mound and control was 5979.92 grains/m~2,4658.73 grains/m~2,3559.28 grains/m~2and 2766.20grains/m~2,respectively.The species diversity of seed bank was reduced by ant-mound.The soil seed bank density was 4143.51 grains/m~2and 4338.55grains/m~2at the yellowing stage and before greening,respectively.On the whole,the seed density of Gramineae,Cyperaceae and Compositae increased on and below the ant-mound,and decreased on Ranunculaceae,Gentiaceae and other forb.Ant-mound changed the proportion of functional group,increased the proportion of superior forage seeds,and reduced the content of inferior forage seeds.Ant-mound promoted the consistency of soil seed bank and above-ground vegetation to a certain extent.In summary,the species diversity of the alpine meadow vegetation community and soil seed bank was decreased by ant mound-building,and the biomass and seed ratio of grasses and sedges were increased,which had a distinct Matthew effect on the dominant species.In order to make full use of high quality forage in ant mound patch,it is suggested grazing can reduce the heterogeneity of ant mound vegetation. |
