Soil macro- and mesofauna-mediated litter decomposition in a subtropical karst forest

This study aims to quantify the effect of different soil fauna on forest litter decomposition processes under natural conditions in the Maolan karst area of southwest China. Leaf litters of two typical evergreen species (CG, Cyclobalanopsis glauca and KS, Kmeria septentrionalis) were selected to conduct a field decomposition experiment using the mesh bags with three different apertures (5, 2, and 0.03 mm). Mass remaining and nutrient variation in the litterbags were determined for one year at 3-month intervals. The results showed that litter decomposition rate in different mesh sizes litterbags were in the order of 5 mm >2 mm >0.03 mm. Soil macrofauna had a significant effect on litter decomposition in the two types of litter and the mixture of the two. The most considerable mesofauna effect was found in the KS litter, which is 36.5% ascribed by the lowest C/N ratio (high quality). Soil mesofauna had a more significant effect on N, which was time-dependent. Moreover, the fauna richness and abundance were affected by the decomposition time but not limited by the litter quality. This study illustrated that soil macrofauna has a significant influence on litter decomposition. The effect of mesofauna on litter mass loss and nitrogen release are determined by litter quality in the subtropical karst forest ecosystems.