Significant Impact of UV Exposure on Litter Decomposition Across Diverse Climate Zones

作者：Sen Yang, Zhou Jia, Pengfei Chang, Yuntao Wu, Junsheng Huang, Jing Wang, Meifeng Deng, Jiao Su, Songbai Hong, Yue He, Juntao Zhu, Pujin Zhang, Yang Wang, Xiaowei Guo, Zhenhua Zhang, Yangjian Zhang, Shuijin Hu, Jin He, Shilong Piao, Lingli Liu · 发表于：Global Change Biology · 年份：2025 · DOI：10.1111/gcb.70456 · 被引用次数：10 · 研究领域：Atmospheric chemistry and aerosols

Litter decomposition is a critical biogeochemical process for carbon and nutrient cycling in terrestrial ecosystems. Ultraviolet (UV) radiation has been recognized to accelerate litter-derived C release in arid and semi-arid ecosystems; yet its spatial controls on determining the regional pattern of litter decomposition are poorly explored. Moreover, the limited understanding of how UV radiation interacts with traditional decomposition drivers, such as climate and litter quality, significantly restricts our ability to accurately quantify the contribution of UV-driven photodegradation to large-scale carbon turnover. In this study, we established a coordinated, distributed UV-manipulation network, spanning 3500-km and covering four grassland ecosystem types, to assess the impact of UV radiation on litter decomposition across gradients of aridity, UV dose, and litter lignin/N ratio. With a modified modeling approach, we further quantified the contribution of UV radiation to litter layer decomposition across temperate grasslands in China. After more than three years in the field, we found that UV attenuation reduced litter mass loss across climatic gradients. The UV-induced facilitation effect primarily occurs in the latter stages of decomposition. The strength of photochemical degradation increased with higher cumulative UV dose, amplified by environmental aridity and litter lignin/N ratio. Across Chinese temperate grasslands, UV exposure shortens mean residence time (MRT) of li...