降水季节性分配格局对亚热带森林典型演替树种凋落叶分解的影响

Seasonal distribution of precipitation has a significant impact on forest litter decomposition. However, few studies have focused on it. Based on the hypothesis that seasonal changes of precipitation can control decomposition environment, change litter quality, influence decomposer communities, and then affect the process of decomposition, and there are different driving effects during different periods, a field experiment will be conducted in the subtropical forest in the middle and lower reaches of the Yangtze River with different seasonal distribution patterns of precipitation. Methods such as field survey and continuous monitoring will be used to investigate the characteristics of foliar litter decomposition of typical successive tree species, litter quality changes, dynamics of microbial communities, and the different responses of foliar litter decomposition to seasonal distribution of precipitation under three seasonal precipitation patterns: “drier dry season, wetter wet season”, “extend dry season” and “extend wet season”. Meanwhile, combined with the dynamic monitoring of temperature, humidity and precipitation, we will reveal the mechanism of seasonal distribution of precipitation affecting litter decomposition, and explore the ecological relationship between litter decomposition in dry and wet seasons. The results of this project will be useful for better understanding the process of material cycling in ecosystem, and will provide some theoretical support to understand the regional response of forest ecosystems under global climate change.

降水季节性分配对森林凋落叶分解具有重大影响，但缺乏必要的关注。基于“降水季节性分配控制分解环境、改变凋落叶质量、影响分解者类群，进而影响凋落叶分解过程，且不同时期具有不同驱动作用”这一科学假设，以具有不同降水季节性分配格局的亚热带森林为研究平台，采用野外调查和实时监测等方法研究“干季更干，湿季更湿”、“干季延长、湿季缩短”和“干季缩短、湿季延长”3种季节性降水分布格局下，典型演替树种凋落叶分解特征、凋落叶质量变化、微生物生物量动态，以及凋落叶分解对降水季节性分配格局的物种响应差异。结合温湿度和降水情况同步动态监测，揭示降水季节性分配格局影响凋落叶分解的作用机制，探明干季和湿季凋落叶分解的生态联系。为更加深入认识森林生态系统物质循环过程，理解全球气候变化背景下森林生态系统的区域响应提供一定的理论支撑。

项目组严格按照计划任务书的要求，我国长江中下游地区的亚热带森林开展研究，以该地区先锋物种马尾松 (Pinus massoniana)、过渡种木荷 (Schima superba)、顶级种青冈 (Cyclobalanopsis glauca) 凋落叶为研究对象凋落叶为研究对象，采用凋落物分解袋的方法，研究了干季更干，湿季更湿，时长不变 (DD)、干季更干，湿季更湿，干季延长 (ED) 和干季更干，湿季更湿，湿季延长 (EW) 等不同降水季节性分配格局下典型物种凋落物分解特征、凋落物质量变化及其对下一阶段凋落物分解的影响。. 研究结果表明，亚热带森林降水季节性分配格局显著影响了凋落物干季分解及养分释放过程，并通过与物种间的交互作用改变凋落物质量进而作用于湿季的分解特征，调控整个凋落物分解过程。与对照相比，干季更干、湿季更湿的降水季节性分配格局都促进了凋落物分解；其中以湿季延长影响最强，以干季延长影响最弱。不同处理间凋落物分解速率按照湿季延长-时长不变-干季延长-对照的顺序依次下降。同时碳、氮、磷的释放和木质素、纤维素的降解动态也表现出类似规律。这在一定程度上表明，与降水量相比，干湿季持续时长的差异可能是影响凋落物分解的重要原因，同时也表明全球气候变化情景下亚热带森林降水季节性分配格局的改变可能显著作用于物质循环等关键生态过程。. 基于以上及相关研究，已发表科技论文2篇，其中SCI收录2篇，授权专利1项。出站博士后1名，培养博士生1名，硕士生2名。