Abstract: Changes in the seasonal distribution of precipitation induced by climate change affect water availability, microbial activity, and related enzyme activities, which may exert an influence on forest litter decomposition, deserving to be further studied. In this study, we examined decomposition dynamics of leaf litter of Phyllostachys violascens and Alangium chinense, two common shrub species in a subtropical evergreen broad-leaved forest in China in different stages of dry and wet seasons from 2020 to 2021 using field in-situ control experiment and litterbag methods. There were three precipitation treatments: control (CK), drier dry season, increased extreme precipitation in wet season (DD), and drier dry season, proportionally increased precipitation in wet season (EW). The results showed that species identity, precipitation treatment, and decomposition stage all affected litter decomposition rate. During the experimental period, the precipitation pattern of drier dry season and wetter wet season (DD and EW) significantly increased decomposition rates of the two types of litter (more than 2.01% for P. violascens and more than 4.69% for A. chinense), and the effect of the proportionally increased precipitation in wet season was the most significant. In addition, the precipitation pattern of drier dry season and wetter wet season increased the contribution rate of the two types of litter in the wet season to the total yearround decomposition, with the effect of proportionally increased precipitation in wet season being more obvious. This is contributed to the precipitation pattern of drier dry season and wetter wet season can indirectly improve litter decomposition by reducing the content of refractory substances and elements in litter through a positive effect on enzyme activity and microbial biomass. As a result of climate change, changes in precipitation distribution patterns will not only affect the decomposition of subtropical forest litter, but also change the contribution rate of dry season and wet season to the total annual decomposition.

Key words: litter decomposition, subtropical forest, global change, biogeochemical cycling, dry and wet seasons