摘要
Background Photodegradation of plant litter plays a pivotal role in the global carbon(C) cycle. In temperate forest ecosystems, the exposure of plant litter to solar radiation can be significantly altered by changes in autumn phenol-ogy and snow cover due to climatic change. How this will affect litter decomposition and nutrient dynamic interact-ing with forest canopy structure(understorey vs. gaps) is uncertain. In the present study, we conducted a field experi-ment using leaf litter of early-fall deciduous Betula platyphylla(Asian white birch) and late-fall deciduous Quercus mongolica(Mongolian oak) to explore the effect of change in autumn solar radiation on dynamics of litter decompo-sition in a gap and understorey of a temperate mixed forest.Results Exposure to the full-spectrum of not only significantly increased the loss of mass, C, and lignin, but also mod-ified N loss through both immobilization and mineralization during the initial decomposition during autumn canopy opening, irrespective of canopy structure and litter species. These effects were mainly driven by the blue-green spectral region of sunlight. Short-term photodegradation by autumn solar radiation had a positive legacy effect on the later decomposition particularly in the forest gap, increasing mass loss by 16% and 19% for Asian white birch and Mongolia oak, respectively.Conclusions Our results suggest that earlier autumn leaf-fall phenology and/or later snow cover due to land-use or climate change would increase the exposure of plant organic matter to solar radiation, and accelerate ecosys-tem processes, C and nutrient cycling in temperate forest ecosystems. The study provides a reference for predictive research on carbon cycling under the background of global climate change.
基金
funded by the National Natural Science Foundation of China(32122059)
the National Key R&D Program of China(2021YFD2200402)
Chi‑nese Academy of Sciences Young Talents Program,and Liaoning Revitalization Talents Program(XLYC2007016)to QWW
by Chinese Academy of Sciences President’s International Fellowship Initiative(2022VCA0010)
the Japan Society for the Promotion of Science(KAKENHI,17F17403)to QWW and HK
Academy of Finland Project(324555)to TMR.
