冬季刈割对黄河三角洲芦苇湿地碳固持效应的影响及其调控机制

Coastal wetlands play a significant role in maintaining global carbon balance and mitigating climate change，which is sensitive to anthropogenic activities. Mowing in winter is common anthropogenic activities in coastal wetlands. However, the studies on the effects of mowing on the carbon sink function of coastal wetlands are still lacking. Based on field observation and laboratory experiments, this project will try to illustrate the mechanism of mowing on carbon sequestration of reed wetlands in Yellow River Delta. We will explore the effect of mowing on plant community structure and reed growth traits of reed wetlands. We will illustrate the variation pattern and response mechanism of net ecosystem carbon exchange, ecosystem respiration and gross primary productivity under mowing in reed wetlands. In order to elucidate the internal mechanism of soil respiration in reed wetlands, the relationship between soil respiration and environment factors, soil carbon fraction, soil enzyme activity and microbial structural diversity under mowing will clarified. We will analyze the effects of mowing on ecosystem carbon storage of reed wetlands. Ultimately, the response characteristics and mechanism of carbon sink function to mowing in reed wetlands will be revealed. Based on this research, we can further know mechanism of carbon sink function changes under the interference of human activities in coastal wetlands of Yellow River Delta, and provide the proofs for the ecological conservation and carbon management of coastal wetlands.

滨海湿地在维持全球碳平衡和减缓气候变化方面起着非常重要的作用，对人类活动变化响应敏感。冬季刈割是滨海湿地常见的人为活动，但有关刈割对滨海湿地碳汇功能的影响研究还很匮乏。本项目拟选取黄河三角洲滨海湿地芦苇群落为研究对象，针对芦苇湿地碳固持效应对刈割的响应这一关键科学问题为主线，基于野外定位观测和室内实验分析，探讨刈割对芦苇湿地群落结构和芦苇生态特征的影响，阐释刈割影响下芦苇湿地的净生态系统碳交换、生态系统呼吸、总初级生产力的变化规律及响应机制；明确刈割作用下芦苇湿地土壤呼吸与环境因子、土壤碳组分、土壤酶活性和微生物多样性的响应关系，识别刈割影响芦苇湿地土壤呼吸的内在机理；辨析刈割对芦苇湿地生态系统碳储量的作用效应，综合剖析芦苇湿地碳汇功能对刈割的响应特征及机理。研究结果有助于深入了解人类活动干扰下黄河三角洲滨海湿地碳汇功能变化的机理，旨在为滨海湿地的生态保育和碳库管理提供理论依据。

滨海湿地在维持全球碳平衡和减缓气候变化方面起着非常重要的作用，对人类活动变化响应敏感。刈割芦苇是滨海湿地常见的人为活动，但有关刈割对滨海湿地碳汇功能的影响研究还很匮乏。项目采用野外实验观测、样品分析、数据整合等手段，揭示芦苇湿地的植物生长特性、群落多样性、生态系统碳交换过程、土壤性质及碳组分对刈割的响应及机制。结果表明:（1）刈割增加了芦苇的茎生物量、叶生物量、根生物量和总生物量，降低了植物根冠比。（2）刈割对芦苇的总碳影响不大，但是提高了芦苇的总氮和总磷含量，促进芦苇对氮和磷的吸收。（3）刈割改变了芦苇湿地的物种数量和组成，增加了芦苇的盖度和密度，降低了物种多样性。（4）净生态系统CO2交换量、生态系统呼吸和土壤呼吸表现出较明显的季节排放规律和年际差异性，刈割增加了净生态系统CO2交换量，提高了芦苇湿地总生态系统初级生产力。（5）刈割增加了总有机碳含量，且通过提高土壤碳组分含量以及酶活性来增加芦苇湿地土壤碳储量。项目研究获得的结果和积累的长期观测数据可为人类活动干扰下黄河三角洲滨海湿地碳汇功能变化的预测和评估提供科学支撑。