多样化松林中昆虫群落多样性特征

马尾松和湿地松是我国南方的2种主要松树。通过对6种不同林分结构下的马尾松林和湿地松林内昆虫群落调查与多样性指数分析,表明2种松树内的昆虫种类和数量无显著差异,混交林中的昆虫群落的种类和数量比纯林多,尤其以捕食天敌类群的种类和数量更为明显。整个昆虫群落和植食类群多样性指数以湿地松林内较大,而天敌(捕食类群和寄生类群)多样性指数则以马尾松林较高。从不同林分结构下昆虫多样性的比较来看,混交林内昆虫群落多样性指数波动较小,明显地高于纯林。但不同林分结构下昆虫多样性随水平分布和垂直分层格局而变化,松树北面和东面各样地之间的昆虫群落多样性指数差异显著,而南、西面之间差异较小;树冠层各样地之间的差异达极显著水平,而枯枝落叶层和树干层之间差异不显著。由此,还进一步讨论了混交林中昆虫群落稳定性问题。

Insect community diversity and abundance in diversified pine forests

Massion pine,Pinus massoniana Lamb,and slash pine,Pinus elliottii Engelm,are the main pines in southern China.The insect species composition and community diversity index were examined in six types of pines forests at 15 d interval.The pine forests include: pure pine forest;mixed pine forest with cogon grass,Imperata cylindrical(L.);mixed pine forest with Chinese fir,Cunninghamia lanceolata(Lamb.) Hook;mixed pine forest with tea-oil camellia,Camellia oleifera Abel;mixed pine forest with camphor tree,Cinnamomum camphora(L.) Presl and Formosan sweetgum,Liquidambar formosana Hance;and mixed pine forest with C.oleifera and L.formosana from mason pine forest and slash pine forest.Our results show that there were no significant difference in insect species and abundance between the massion pine forest and the slash pine forest.However,significantly higher community diversity index of total insects and phytophagous group and lower community diversity index of predatory and parasitic natural enemies were observed in slash pine forest.Insect species and abundance,especially the predatory natural enemies,from the mixed forests are significant higher than those from the pure forests.The community diversity indices of total insects,predatory and parasitic natural enemies in the mixed forests were relatively stable during the year,and were significantly higher than those in the pure forests.However,the insect community diversity indices varied among locations and vertical layers of the trees.Significant differences in diversity index of insect community were observed in the direction of the northern and eastern parts of the canopy of the pine trees,but no such differences in the southern and western parts of the tree canopy.Similarly,significant difference in diversity index of insect community occurred on trunk but not on canopy and litter layer of trees.The stability of insect community in the mixed pine forest was discussed.