南亚热带常绿阔叶林不同大小和发育阶段林隙的树种多样性研究

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〈４０００ｍ＾２的林隙中变化不大，但在４００－５００ｍ＾２的林隙中达到最大，而在５００－６００ｍ＾的林隙中最小，在〉６００ｍ＾２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２０－５０年期间的多样性最大，其次是２０年以下的，５０年以后的多样性相对最小，林隙更

Tree species diversity in gaps of different sizes and developmental stages in lower subtropical evergreen broadleaved forest,South China

The change pattern of tree species diversity in gaps of different sizes and developmental stages in the lower subtropical evergreen broadleaved forest was analyzed in this paper. The species diversity index(Shannon-Wienner) did not change in the gaps with a size of < 400 m2, reached the highest in those with a size of 400-500 m2 and the lowest in the gaps of 500-600 m2 size, and increased in those with a size of > 600 m2. The index was the highest in the middle period of 20-50 years, secondly high within 20 years, and lowest after 50 years of gap formation. The species diversity in regeneration layer(H < 1.5 m) reached a peak in the gaps with a size of 500-600 m2, and the lowest values occurred at the gaps with a size of > 600 m2 and 200-300 m2. Species diversity index in the regeneration layer reached the highest in the first 10 years after gap formation, then revealed a general trend of decreasing, but two relative peaks were formed in the gap ages of about 30-40 years and 50-60 years, respectively. The general trends of species richness were correspondent with those of species diversity index. Gaps of different sizes and ages had a strong influence on the tree species regeneration through changes of ecological factors in gaps, thus, tree species diversity was different in gaps of different sizes and ages. Gap is one of the most important mechanisms for the maintenance of tree species diversity in the lower subtropical evergreen broadleaved forest.