湖泊生态系统反馈机制与突变早期信号

Lake ecosystem is one of typical castraphic ecosystems, i.e it has abrupt changes and hystersis, so that the detections of early warning signals preceding critical transitions are important for lake managements. According to system dynamic theory, lake ecosystem's stability depends on interactions among lake's feedbacks. Therefore, it is critical for early warning signals detectors to know the long trend of system's feedbacks change so that false positive conclusions can be avoided. This project will aim to reconstruct trajectory of lake's ecosystem change based on palaeoecological proxies (diatoms, pigment and cladocera) and palaeoenvironmental proxies (such as grain size, TOC/TN, magnetic susceptibility and elements). Instrumental records and models will be also employed for study of lake's feedback changes in long term trend and early warning signals in different biological communities of a lake. The purpose of this research is to extend the theory of ecosystem's abrupt change and applications of early warning signals on lake's management.

湖泊生态系统是典型的多稳态灾变系统。突变一旦发生，生态系统就难以修复，而早期信号的提取可以预警突变的发生。深入理解湖泊生态系统反馈机制的变化，揭示不同生物种群变化响应环境压力的差异，有助于系统突变早期信号的研究。本项研究拟通过洱海浅钻沉积记录的高分辨率定年、多个古生态指标（硅藻、色素和枝角类）和环境替代指标（粒度、有机碳/氮、磁化率、元素地化等）的分析，重建近百年来生态环境演化的历史过程；结合湖泊监测数据和模型模拟数据，系统阐述湖泊生态系统突变过程中反馈机制的变化特征，以及早期信号在不同生物种群以及同一生物内部不同属种中的表征差异。该研究将拓展古生态学研究的范畴，可望进一步丰富生态系统突变理论，并为湖泊生态系统修复提供理论指导。