关键词: 松嫩沙地, 天然草地, 人工草地, 土壤动物

Abstract: Ecological study on soil animals has a history of only twenty years in our country, but mainly lays particular emphasis on the forest aspect. Study on the grassland aspect is less and only limited in natural grassland. This article makes a contrastive study on the soil animals in natural grassland and artificial grassland of Songnen sandy land. The dominant groups of large sized soil animals in natural grassland have 3 groups which are Formicidae, Staphylinidae and Aranida. Those of middle and small sized soil animals have 1 group which is Nematoda. The dominant groups of large sized soil animals in artificial grassland have 3 groups which are Formicidae, Scarabaeidae and Lygaeidae. Those of middle and small sized soil animals have 2 groups which are Nematoda and Actinedida. The dominant groups in natural grassland and artificial grassland are similar in number, but the group composition has some difference. The common groups of large sized soil animals in natural grassland have 9 groups and those of middle and small sized soil animals have 5 groups. The common groups of large sized soil animals in artificial grassland have 4 groups and those of middle and small sized soil animals have 4 groups. Natural grassland is the main type in Sonnen sandy land and has a large distribution area. Because of its large plant community cover, high biomass and high soil nutrient content, the common groups in natural grassland are more than those in artificial grassland. The rare groups of large sized soil animals in natural grassland have 5 groups and those of middle and small sized soil animals have 12 groups. The rare groups of large sized soil animals in artificial grassland have 7 groups and those of middle and small sized soil animals have 15 groups. Because artificial grassland is less influenced, the rare groups of soil animals in it are more than those in natural grassland. In horizontal distribution of soil animals, the large sized groups in natural grassland are more than those in artificial land, but the middle and small sized groups demonstrate the opposite pattern and soil animals in two grassland types have obvious difference in group composition. It shows that these groups have stronger choice over habitat and soil animals have certain instruction over different soil types. The vertical distribution of the soil animals in two grassland types is different, but basically its amount is decreased with soil depth increasing. The groups of soil animals in surface layer of natural grassland are more than those of artificial grassland and its amount is mainly restricted by the soil nutrient conditions and soil physical and chemical properties.

Key words: Songnen sandy land, Natural grassland, Artificial grassland, Soil animals