Species-Specific Effects of Litter Management on Soil Respiration Dynamics in Urban Green Spaces: Implications for Carbon Cycling and Climate Regulation

The disposal of urban tree litter as waste has significant implications for material cycles, energy flows, and global climate change within urban ecosystems. However, the species-specific contributions of urban trees to atmospheric CO2 emissions through soil respiration (RS) remain poorly understood. This study investigates the effects of litter management on RS dynamics in urban green spaces, focusing on six common species (Mangifera indica, Ficus microcarpa, Cinnamomum camphora, Bauhinia purpurea, Triadica sebifera, and Celtis sinensis) in Fuzhou, China. Three litter treatments—litter retention (CK), litter removal (RL), and litter doubling (DL)—were established to monitor monthly RS fluctuations. Results indicate that DL significantly increased RS rates, while RL reduced them. The increase in RS due to litter addition was more pronounced than the decrease caused by litter removal for most species. RS rates exhibited a unimodal seasonal pattern, peaking in summer. Furthermore, litter treatments influenced the temperature sensitivity coefficient (Q10), with F. microcarpa showing the highest average Q10 (4.16) and M. indica the lowest (1.88). This study underscores the critical role of litter input in modulating RS in urban green spaces and highlights the joint but asymmetric effects of soil temperature and moisture on RS dynamics.