喀斯特森林林隙梯度物种多样性变化规律

Species diversity change pattern in gap gradient in karst forest in Maolan Nature Reserve, Guizhou Province

关键词:  喀斯特森林  物种多样性  林隙梯度  茂兰

Key words:  karst forest  species diversity  gap gradient  Maolan

摘要:

采用Margalef物种丰富度指数(R1)、Shannon-Wiener指数(H')及Pielou均匀度指数(J)来研究物种多样性的林隙梯度变化。结果表明:从林隙中心至非林隙林地的水平梯度上,林隙不同区域的种类组成存在较大差异,一些阳性树种如圆果化香等在林隙中心分布较多,青冈等耐荫性强的树种则在郁闭林下较为丰富,而中度耐荫种类如香叶树、大叶冬青等则集中分布在林隙近中心和林隙边缘处。从非林隙到林隙中心,物种丰富度逐渐升高,即非林隙<林隙边缘<林隙近中心<林隙中心; 物种多样性的变化则总体呈中间高两头低的现象,均匀度的变化与其一致; 物种多样性林隙梯度变化程度受林隙发育期和面积的影响较大,变化程度为早期林隙>中期林隙>晚期林隙,大林隙>中等林隙>小林隙,早期林隙和大林隙的边缘效应显著。

Abstract:

To research the species diversity change pattern in gap gradients. The Margalef index,Shannon-Wiener index and Pielou evenness index were computed with the data from gaps investigation in karst forest in Maolan Nature Reserve. The results showed that species composition was different greatly in different gap area from gap center to non-gap. Some light-demanding species such as Platycarya longipes was much in gap center area,shade-tolerant species such as Quercus glarca was much in non-gap area and moderate shade-tolerant species such as Lindera communis and Ilex latifolia was much in near gap center and gap border area. Species richness index gradually increased from non-gap to the gap center area,such that:Non-gap<Gap border<Near gap center<Gap center; Species diversity index change pattern was high in the center and low on edges. The change of evenness index coincided with species diversity index. The degree of species diversity change in gap gradients was affected heavily by gap phase and gap size,the degree of change was:Early phase gap>Middle phase gap>Late phase gap and Large size gap>Middle size gap>Small size gap. Early phase gap and large size gap had remarkable edge effect.