Abstract:

In order to supply a scientific basis for natural forests regeneration affected by artificial disturbance，this paper studied effects of forest gap on plant diversity of natural Quercus liaotungensis community in the Ziwuling Mountain of the Loess Plateau. On the basis of investigation of 26 gaps and the non-gap stand, using species richness index, Simpson diversity index, Shannon-Wiener diversity index and Pielou evenness index, plant diversity in gaps and under closed canopy were compared. The results indicated that: (1) The average area of gaps which were regimed by the natural disturbance was 86.3 m2 in the natural Quercus liaotungensis community, primarily (accounted for 76.9%) formed by small gaps with the area below 100 m2. And the main formation of them were breakage at trunk base. (2) There was a significant difference between plant diversity in gaps and under canopy, diversity index and richness index were slightly higher in gaps(P＜0.05). (3) Diversity index, richness index and evenness index of arbor and shrub layers were the highest in the size of 75~100 m2 in gap. But diversity index and evenness index of herb layer reached the highest in the size of 0~50 m2, and richness index reached the highest in the size of 75~100 m2 in gap.