Structural And Functional Succession Of Decomposer Fauna During Debris Decomposition-a Study Of Microcosm

By establishing 72 soil microcosms, the numerical changes and community succession of decomposer fauna during the debris decomposition were studied, the numerical structure, biomass structure, communities biodiversity and functional succession of decomposer fauna were analyzed, the effects of decomposed resource quality and soil biota on the decomposition of organic material in soil was examined. The four treatments included litter +coarse mesh (LC), litter +fine mesh (LF), straw +coarse mesh (SC), straw +fine mesh (SF). The results show that:1. The decomposition included three phrases, which characterized as prompt startup of decomposition (0-20 days) , steady decomposition (20-90 days) and stasis of decomposition (90-160days).2. Five groups of animals, namely protozoa, nematode, acaria, rotifer and tardigrade, were observed during the experimental period, the numerical curves of animals during the experimental period showed as one apex or two apices. Protozoa was absolutely dominated in number, nematode and acaria were the main companion groups.3. The total numerical changes of whole decomposer fauna was mainly controlled by the number of protozoa. Although the quantities of nematode and acaria were small, the total biomass change of decomposer fauna was mainly influenced by them, since the body sizes of nematode and acaria were much bigger than that of protozoa.4. The succession of decomposer fauna distinctly showed as three phrases compared to the three phrases of decomposition. Protozoa and nematode were observed in every sampling, and only protozoa and nematode were observed from 0 to 20 days; acaria, rotifer and tardigrade were observed one by one and increased to their numerical apices from 20 to 90 days; 90-160 days was the third phrase, the quantities of almost all groups of decomposer animals showed the trend of decrease.5. The biodiversity of decomposer fauna was a little different among different treatments during the experimental period, but these differences showed no significance (P>0.05). The Shannon-wiener diversity index of decomposer fauna from 20 to 60 days was relatively higher than that of other period during the whole experimental period.6. The difference of decomposed resources leaded to some differences of decomposition process, such as the communities respiration and decomposition rate, however the eventual effect of decomposition showed no significance (P>0.05).