南泥湾片段森林蝗虫群落多样性比较

应用多样性指数、排序和多元逐步回归分析方法比较了南泥湾片断化森林的蝗虫群落结构，并进行了环境因素的解释。结果显示：在南泥湾，树木破坏不严重的片断化森林，随森林面积的减小，林缘草层蝗虫种类、多样性指数和均匀度指数差异不大；林中草层蝗虫密度、多样性指数和均匀度指数减小。在面积小、树木破坏严重、植被结构发生明显改变的片断森林林中草层，相对于树木破坏不严重的片断化森林，蝗虫的密度、多样性指数和均匀度指数明显增大；而林缘草层蝗虫的密度和群落优势度指数上升，多样性指数和均匀度指数下降。以主分量分析方法可明显将林中草层蝗虫群落分为森林破坏严重和不严重两种类型。通过多元逐步回归分析发现，影响片断化森林蝗虫群落结构和多样性的主要因素有片断森林面积、森林植被结构的复杂性、食料植物的多少等几个方面。

Comparisons of diversity of grasshopper community in fragmentary forest of Nanniwan

Forest fragmentation is a key factor affecting the insect. The study had principally been carried out in tropical area in China. The paper studies the grasshopper community structures of north china's Nanniwan fragmentary forest using principal component analysis(PCA) and stepwise regression analysis. The results show that there are 12 species of grasshopper in both edge forest and inner forest of the region, which belong to 5 families,12 genuses. When forest vegetation structure doesn't change drastically, the species, diversity index ,dominant index and evenness index of grasshoppers change slightly in forest edge grasses, whereas the density, diversity index and evenness index of grasshoppers in grasses of inner forest decrease with area of forest reducing. In severely damaged forest, in comparison with slightly damaged forest, the vegetation undergoes obvious changes, the species, density, diversity index and evenness index of grasshoppers in grasses of inner forest show signs of obvious increase, the density, dominant index of grasshoppers in grasses of edge forests increase, the diversity index and evenness index decrease. Using principal component analysis(PCA),the grasshopper community structures of fragmentary forest can be divided into two types: the slightly damaged forest and the severely damaged forest. It shows, by stepwise regression analysis,that the area of fragmentary forest and the structure of vegetation and food are important factors, which affect the structure and diversity of grasshopper community.