Influences Of Secondary Succession Of The Damaged Evergreen Broad-leaved Forest On Soil Animal Community In Tiantong, Zhejiang Province

As an important integrant of forest ecological system, soil animals are indispensable to its nutrient cycling and energy flowing. There exists dynamic interplay between soil animal communities and plant communities. Seen from the angel of ecological system, the succession of plant communities above the ground will inevitably influence soil animal communities below. By decomposing litter, feeding on plant roots and moving in the soil, soil animals change physico-chemical properties of soil and thus directly or indirectly affect the structure, function and succession of plant communities. Researches on the interaction between soil animal communities and plant commnities have become one of the hot research topics in soil animal studies outside China, but few similar reports have been seen in China.The sampling sites chosen for this study included six plant communities at diffferent secondary succession stages of the damaged Evergreen Broad-leaved Forests (EBLF) in Tiantong, Zhejiang Province, namely bare land, Loropetalum chinensis-Lithocarpus glabre community, Pinus massoniana community, Pinus massoniana-Schima superba community, Schima superba community and Castanopsis fargesii community. An all-round four-season investigation was conducted into the soil animal communities, including macrofauna, mesofuana and wet types of soil animals in the litter and soil in the above plant communities from the autumn of 2003 to the summer of 2004. Samples were taken in the litter in accordance with fresh litter layer (L), fermentation layer (F) and humus layer (H), while in the soil below the litter, the soil depth of 0-5cm, 5-10cm and 10-15cm. In the meantime, the temperature, humidity and nutrients contents in the litter and soil at different succession stages were also tested and analyzed. By using the litter bag method, a comparative experiment was carried out in the decomposition of soil animals in Pinus massoniana community at the intermediate succession stage and Castanopsis fargesii community at the climax succession stage.Based on a comprehensive knowledge of the features of soil animal community in the damaged EBLF and by employing the subustitution method of space for time, the paper probed into the influences of secondary succession of plant communities on the structure of soil animal communities, and analyzed the relevance of main environmental factors to soil animal coummnities in the succession process of plant communities, as well as those influences of change of soil animal communities on litter decomposition and nutrients release. This will contribute to an understanding of the role of soil animals in thesuccession of plant communities and is theoretically of great significance to further exploration of the internal mechanism of vegetation degradation. The major findings are as follows:1. Soil fauna in the forest ecological system in Tiantong were very abundant. The macrofauna, mesofuana and wet types of soil animals, captured in the four seasons of a year, amounted to 73, 764 in number, falling into 10 classes and 29 groups respectively. The dominant groups were Nematoda and Acarina, both accounting for 84.52% of the total, the density of Nematoda being 1.31 times that of Acarina; the common groups were Collembola, Enchytraeidae, Diptera and Hymenoptera, altogether making up 14.02%, with Collembola the most abundant, accounting for 8.47%. There were 25 groups of mesofauna, with Acarina and Collembola the dominant ones, A/C value was 4.32. There were 20 groups of macrofauna by hand sorting, mainly including Coleoptera and their larvae, Hymenoptera, Isoptera and Diplopoda.2. The numbers of groups and individuals in the litter were much greater than in the soil, and 73.91% of individual soil animals were found in the former, with a noticeable vertical distribution. There were a relatively small number of groups and individuals in the fresh litter layer, with 70.55% of the individuals seen in the fermentation layer and humus layer and the number in the former accounting for 38.84%. Acarina predominated in th...