| Based on the grassland vegetation in the Xilin River Basin, the species importance values, and α, β diversity index were used to study the distribution of plant community diversity along the altitudinal gradient. At each altitude gradient, Leymus chinensis was dominated. With the increase of the altitude gradient, α diversity index trended to decrease first and then increase. To the affected extent of Simpson diversity index, the richness index was higher than the evenness index. With the increase of the elevation gradient, β diversity index trended to decrease first and then increase, then decrease again. The species had high similarity between 1 200 m and 1 300 m, and between 1 300 m and 1 400 m altitudinal gradient. The species replacement rate was slow. At the altitude gradient of 1 100 m～1 200 m and 1 200 m～1 300 m, the species composition had distinct difference, and the species replacement rate was rapid. |
