放牧强度对短花针茅荒漠草原甲虫群落分布格局的影响

放牧对脆弱的荒漠草原生态系统有着重要影响,且随放牧强度及持续时间不同而变化。鞘翅目昆虫是环境监测与生物多样性变化的指示生物。利用巴氏罐诱法对短花针茅荒漠草原不同放牧强度草地的甲虫群落组成和多样性进行调查,探究放牧对荒漠草原甲虫群落的影响。结果表明:(1)步甲科、金龟科为短花针茅荒漠草原甲虫群落优势类群,埋葬甲科、芫菁科、拟步甲科和花金龟科为常见类群。(2)放牧强度增加不利于维持更多的捕食性甲虫;对照和轻度放牧样地可维持更多的腐食性甲虫。(3)甲虫数量随放牧强度增加而递减;群落多样性以重度放牧草地最大,轻度放牧草地最小;群落优势度为对照、中度、重度显著高于轻度放牧草地。各甲虫类群在不同放牧强度草地出现时间、高峰期均不同。(4)对照、轻度、重度放牧样地的甲虫优势类群群落结构不同于其他生境,但均与中度放牧样地存在相似性。轻度、中度、重度放牧样地的甲虫稀有类群群落结构不同于其他生境,但均与对照样地存在相似性。(5)甲虫群落个体数与植物群落物种丰富度、盖度、植物平均高度、生物量呈显著正相关。Shannon-Wiener多样性指数、Margalef丰富度指数均与植物群落物种丰富度、生物量显著负相关。研究结果为荒漠草原甲虫多样性保护提供参考依据。

Effects of different grazing intensities on the community structure of beetle community in Stipa breviflora desert steppe

Grazing has an important effect on grassland ecosystem, and the effect varies with the grazing intensity and duration. The desert steppe ecosystem is fragile and sensitive to natural and human disturbance. Coleoptera is an indicator of environmental monitoring and biodiversity change. This study investigated the composition and diversity of beetle community in steppe at different grazing intensities using baited pitfall traps. The results showed that (1) the dominant groups were pegasidae, dionychidae and scarabaeidae. The common groups were silphidae, meloidae, enebrionidae and cetoniidae. (2) The increased grazing intensity was not conducive to maintaining more predatory insects. Control and lightly grazed plots maintained more carrion beetles. (3) The number of beetles decreased with the increase of grazing intensity. However, the community diversity was the largest in heavily grazed grassland and the smallest in lightly grazed grassland. Community dominance was significantly higher than that of lightly grazed grassland. The occurrence time and the peak quantity of each beetle group were different in different grazing intensity grasslands, and the dominance degree of the same habitat also changed with time. (4) The dominant groups of beetles in control, light and heavy grazing plots were different from other habitats, but all of them were similar to moderate grazing plots. The community structure of rare beetle groups in the lightly, moderately and heavily grazed areas was different from that of other habitats, but all of them were similar to that of the other habitats. (5) The number of individuals in beetle community was significantly positive correlation with species richness, coverage, average plant height, biomass. Shannon-wiener diversity index and Margalef richness index were significantly negative correlated with plant community species richness and biomass. The results can provide a reference for the protection of coleoptera diversity in the desert steppe.