Indoor evidence for the contribution of soil microbes and corresponding environments to the decomposition of Pinus massoniana and Castanopsis sclerophylla litter from Thousand Island Lake

Soil organisms are important in mediating nutrient availability to independent ecosystem for maintaining environment balance. Microbial communities on artificial islands are depauperate due to the influence of biogeographic processes and interference. Thus, there may be an advantage to island ecosystem that explor soil microbial function differentiation for better understand the potential ecological process. Here, we used simulation method in laboratory, created a series of microcosms to examine the decomposition mechanism of soil decomposer on litter decomposition rate of Pinus massoniana and Castanopsis sclerophylla collected from 28 islands in Thousand Island Lake forest.The average decomposition rate of low-quality P. massoniana litter was less than that of high-quality C. sclerophylla in most soils. Substrate-induced respiration (SIR) was various among island soils, and it correlated with litter quality and soil N content. N content of both decomposing litter was accumulation, while litter N content was negatively correlated with island area. The litter decomposition rate of P. massoniana was higher in most small island soils than in other island soils. Soil cellulase and cellobiohydrolase activities were significantly positively correlated with two litters decomposition rate. Nitrate reductase and urease were significantly positively correlated with island area. Phenol oxidase, peroxidase activities were positively correlated with decomposition rate of P. massoniana litter, implying that special soil enzymes dominated and improved P. massoniana decomposition especially in its home field soils. Result showed that P. massoniana was sensitive to home-field advantage (HFA) in these potential island ecosystems. By contrast. the decomposition rate of C. sclerophylla litter did not significantly differ among the soils. In summary, the responses of litter decomposition to island ecosystems were dependent on soil nutrient balance and interaction between litter property and soil microbial communities.