内蒙古草原带土壤动物生态学研究

The Study on Soil Animal Ecology in Inner Mongolia Grassland.

传统通用的土壤动物的分离方法困惑着草原、荒漠、沙地土壤动物的研究，土壤动物分离盒的使用解决了漏沙、漏土的难题。大针茅草原、羊草草原的土壤动物群落结构、密度、生物量与分布特征在草原带具有代表性；不同类型的草原土壤动物的群落结构、密度、优势类群、生物量有各自的特异性。各优势类群，尤其鞘翅目昆虫、线蚓的动态变化可作为草场退化的生物指标；对１７种拟步甲科昆虫在荒漠化草原、退化草原、典型草原中的分布进行了比较，认为也可作为草原退化的生物指标。天然与实验放牧条件下，随牧压加强土壤动物各综合多样性指数与牧压呈负关联，出现优势类群单调与多样性、均匀性、种的丰富度降低的趋势，但密度、生物量降低不明显。定量放牧（４～８只羊／ｈｍ２）与自然放牧（轻中牧压）对土壤动物的影响相似。火生态因子对表聚性及地表自由生活的土壤动物直接致死作用明显，间接影响线蚓及鞘翅类等土壤动物密度；火烧后膜翅类、鞘翅类恢复较快、螨类则较慢；小面积火烧后经竞争新空间约３年可形成新的动态平衡。

In Inner Mongolia grassland, 6 phyla, 10 classes, 18 orders of soil animals were found. The soil animal community, density, biomass in Stipa grandis steppe and Aneurolepidium chinense steppe are the typical types in Inner Mongolia grassland. In this area, the dominant groups of soil animal community are Nematoda, Acarina, Coleoptera and Hymenoptera. The typical group of soil animal is Coleoptera. As for different grassland types, they have different features of soil animal community structure, dominant groups, and different soil animal densities, and biomass. Through comparison on the distribution of 17 species of Tenebrionidae, it can be concluded that the distribution of Tenebrionidae may be the biological index for grassland degeneration. The dynamics of soil animal dominant groups, especially Cleoptera and Enchytradae can also be the biological index for grassland degeneration. Under the condition of natural and experimental grazing pressures, the relation between biodiversi ty of soil animal community and the incereasing of grazing pressures are negative. As the increase of grazing pressures, the composition of soil animal dominant groups are simplified. Biodiversity and evenness, richness of soil animal community are declined. The decrease of soil animal density and biomass are not obvious. The effects of the experimental grazing pressures of 48 sheep per hectare are similar to the effects of lightly and middle natural grazing pressures. The fire ecological factor can directly kill the soil animal groups which live in the upper soil layer. The indirect effects of burning is the disturbance of the soil animal density dynamic. After burning, the recoverings of Hymenoptera and Coleoptera are fast, and the recovering of Acarina is slow. After three years of burning, the soil animal community can form new dynamic balance. The routine method of soil animal collection is not suitable in the grassland, desert and sandy lands. In this paper, we described the using of separete box and watering method in our studies. Both these methods can overcome the problems of leap soil and sand.\