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分析了南亚热带常绿阔叶林不同大小和发育阶段林隙内树种多样性的变化规律 .结果表明 ,在南亚热带常绿阔叶林中 ,多样性指数在 <40 0m2 的林隙中变化不大 ,但在 40 0～ 5 0 0m2 的林隙中达到最大 ,而在 5 0 0～60 0m2 的林隙中最小 ,在 >60 0m2 的林隙中又有所增大 .树种多样性指数随林隙年龄的变化趋势是中间高两端低 ,即在 2 0～ 5 0年期间的多样性最大 ,其次是 2 0年以下的 ,5 0年以后的多样性相对最小 .林隙更新层中树种多样性指数在 5 0 0～ 60 0m2 的林隙中达到最大 ,在 >60 0m2 和 2 0 0～ 3 0 0m2 的林隙中最小 .林隙更新层树种多样性指数在林隙形成最初的 10年内达到最大值 ,但随着林隙年龄的增加 ,总体上表现出下降趋势 ,在 3 0～ 40年和 5 0～ 60年左右又分别形成两个相对的峰值 .物种丰富度的变化趋势总体上与树种多样性指数相一致 .不同大小和发育阶段的林隙通过其生态因子的改变 ,对不同树种的更新起到了不同的作用 ,从而使得不同大小和发育阶段的林隙中树种的多样性特征不同 .林隙是维持南亚热带常绿阔叶林树种多样性的一个重要机制
The variation of tree species diversity in the gaps of different size and development stage in the subtropical evergreen broad-leaved forest in South China was analyzed.The results showed that in the evergreen broad-leaved forest in the south subtropical zone, the diversity index changed little in <40 0 m 2 gaps, But reached the maximum in the gap of 40 0 ~ 500 m 2, but the smallest was in the gap of 500 ~ 60 0 m 2 and increased in the gap of> 60 0 m 2. The diversity index of tree species increased with the gap The trend of age is that the middle and high ends are low, that is, the diversity is the highest between 20 and 50 years, the next is below 20 years, and the diversity is relatively minimum after 50 years. The sex index reached the maximum in the gap between 500 and 600 m 2, and the smallest among the gaps between> 60 0m 2 and 200 ~ 300 m 2. The index of species diversity in the gap regeneration layer was within the first 10 years Reaching the maximum value, but with the increase of the age of gap, the overall trend showed a downward trend, and two relative peaks were formed respectively from 30 to 40 years and from 50 to 60 years respectively.The trend of species richness generally The tree species diversity index is consistent with the different size and development stage of the gap The change of ecological factors played different roles in the regeneration of different tree species, which led to the differences in the species diversity of species in gaps of different sizes and developmental stages. The gap was to maintain the species diversity of the evergreen broad-leaved forest in the subtropical zone An important mechanism