草原沙化和人工固沙草地生态演替中昆虫群落多样性变化的数值分析

对宁夏沙坡头自然保护区不同沙化和人工固沙草地地段昆虫和植物群落特征参数、环境因子进行了调查．按不同营养层类群、栖息型类群和重要目分别进行了昆虫多样性变化规律的研究，应用主分量分析法和相关分析法，分析了草原沙化和人工固沙草地生态演替中昆虫不同类群多样性间以及多样性变化与植物、环境因子的关系．结果表明，昆虫多样性随草地沙化的加重而降低，以直翅目、膜翅目和食叶类群的下降率最大；随草地的恢复昆虫多样性趋于增加，以鳞翅目、同翅目、半翅目、脉翅目及捕食类群增长率为大．寄生类群和捕食类群多样性取决于植食类群多样性；杂食类群与地栖性类群成显著性相关．影响昆虫多样性变化的主要环境因子为植物种类、层次结构、盖度和表土层厚度、坚硬度等．

NUMERICAL ANALYSIS FOR DYNAMICS OF INSECT COMMUNITY DIVERSITY IN THE ECOLOGICAL SUCCESSION OF DESERTIFIED AND ARTIFICIAL SAND-FIXED GRASSLANDS

The insects, plants and environmental factors in different desertified and artificial sand-fixed grasslands in Shapotou, Ningxia were investigated systematically. According to the different trophic groups, habitat groups and main orders,the dynamics of insect community diversity was analyzed.Both principle component analysis and correlation analysis were used for studying the relationship between the diversities of different groups and the dynamics of diversity and environmental factors in the ecological succession of the grasslands. The results showed that the insect diversity decreased with the worsening of grassland desertification and increased with the recovering of vegetation in artificial sand-fixed regions. The environmental factors of causing changes in insect diversity in the two changing grasslands were mainly plant species, vegetation structure, coverage, and thickness and hardness of topsoil.