Songnen Steppe Pastoral Forest Complex Ecosystem Of Soil Animals

Soil animals, the constituents of terrestrial ecosystem, are important consumers and special decomposers, and they are unusually significative to ecosystem. Study on community ecology of soil animals, viz. study on ecogeography of soil animals, is the important component of the study onglobal terrestrial ecosystem. The study of soil animals will provide significant theory gist and basic information to the restoration of grassland ecosystem and the ecotone ecosystem of grassland and farmland in the grassland region of Songnen Plain.The research plot of this paper is the compound ecosystem of woodland, grassland and farmland in the grassland region of Songnen Plain. In the three subsystems of compound ecosystem, samplings are made twice in August and October of 2001. From the ecogeographical angle, using the theory and measure of soil zoology and ecology, this paper analyses the compound ecosystem. Particularity of compound ecosystem and the comparability and difference between ecosystems in the study region and those in other areas are found.In the compound ecosystem, 14793 soil animals that belong to 73 groups are obtained. The dominant groups of soil animals (including large-size and middle-small-size) are Hypogastruridae, Actinedida, Gamasida and Oribatida.The common groups are Formicidae, larvas of Scarabaeidae, Isotomidae, Araneida and imagoes of Coleoptera. The number of rare groups is 61.The number of groups of soil animals in grassland is larger than that in woodland, and that in woodland is larger than that in farmland. The individual number in grassland is largest and that in farmland is larger than that in woodland. The habitat of grassland is superior to the other two. And the horizontal distribution of soil animals is unequal. The verticaldistribution of soil animals is descending with the increasing of depth of soil layers. Thereinto the individual numbers put up obvious nature of surface gathering, and the numbers of groups are equable descending.The composition and structure of soil animals community in different seasons are different. The number of groups in summer is higher distinctly than that in autumn but the individual number are pretty nearly. The diversity of soil animals community in grassland is highest, and that in farmland is lowest.The correlation between the individual number and soil environmental elements is obvious, but the correlation between the number of groups and soil environmental elements is not. But pH affects both the individual number and the number of groups. In climatic factors, only the correlation between the number of groups and ground temperature and that between the number of groups and evaporation are better. The effect of climatic factors on large-size soil animals are more than on middle-small-size soil animals, and the influence of siol elements on middle-small-size soil animals are more than on large-size soil animals.In function classification of soil animals, the proportion of mixture-ate groups is largest, next is litter-ate, root-ate and prey-ate groups, and rottenness-ate groups is least. So the important groups of soil animals are more action on matter decomposition than on melioration of soil structure.As a result, the soil animals community in compound ecosystem is different from that in common ecosystems. And soil animals communities in different region are quite different.