马尾松林节肢动物群落的组成及多样性

在不采取任何营林和治虫措施的皖南九连山林场马尾松纯林中设林分相似的2块样地,面积均为22m×22m。1997年1月～1998年12月，每月1次垂直分层对两样地节肢动物群落的调查表明每样地植食性、捕食性、寄生性昆虫和蜘蛛类群的物种数占该样地总物种数的百分比分别约52%、14%、8%和20%；每样地的益害物种数之比都约为11.2；益害个体数之比是15.7和16.6；相同林间层次的优势目昆虫或优势种蜘蛛相同；每样地的物种数量都是以灌木草本层最多，依次为乔木层、枯枝落叶层和土壤层。两样地乔木层、灌木草本层、土壤层和枯枝落叶层的节肢动物平均个体数百分率分别为39.6%、33.1%、22.8%和4.6%。3～8月物种数和多样性指数较大，5、8月为物种数高峰期。主成分分析显示群落的稳定性较差。

Composition and diversity of Arthopod community in Masson Pine stands

Arthopod communities in various layers of pine stands were investigated from January 1997 to December 1998 in two sample plots with similar stands and equivalent area (22 m×22 m) and without any sylvicultural and pest-suppressing measures in the Jiulianshan Forest Farm in Southern Anhui Province. In every sample plot the percentages of species number of phytophagous, predatory, and parasitic insects and spiders that accounted for the total species number were about 52%, 14%, 8% and 20%, respectively. The ratio of beneficial to harmful species numbers was around 11.2 in each sample plot; the ratio of beneficial to harmful organism individual numbers was 15.7 and 16.6, respectively . Dominant groups existed in the same layers of the two sampling plots . Species number ranked in the following order: brush and herb layer > tree layer > litter layer > soil layer. Averages of the individual percentage of tree layer, brush and herb layer, litter layer and soil layer in two sample plots were 39.6%, 33.1%, 22.8% and 4.6%, respectively. The species number and index of diversity from March to August were largest, and there were two peaks emerging in May and August, respectively. Principal component analysis indicated that recovery-stability of this kinds of community was not strong, and the natural control potential was weak.