[Niche characteristics of plant populations in Quercus aliena var. acuteserrata stands in Qinling Mountains].

Based on the data collected from 31 plots and using Levins, Hurlbert and Pianka formulas, this paper calculated and analyzed the niche breadths and overlaps of 24 tree and 29 shrub populations in Quercus aliena var. acuteserrata stands in Mt. Qinling, Shaanxi. The results showed that the Levins and Hurlbert's niche breadths of Quercus aliena var. acuteserrata , Pinus armandi, Toxicodendron vernicifluum, Populus davidiana and Pinus tabulaeformis in arbor layer were 3.695, 1.695, 1.325, 0.840, 0.702 and 0.036, 0.299, 0.568, 1.721, 2.701 respectively, and those of Corrylus heterophylla, Lespedeza formosa and Smilax vaginata in shrub layer were 1.833, 1.466, 0.984 and 0.111, 0.300, 0.594, respectively. In general, the niche overlaps between the species with bigger niche breadth and other species were higher, and those of the species having similar environmental requirements were also higher.