西双版纳热带雨林生态化学计量比与元素变化特征及其对环境响应研究

The drought degree of Xishuangbanna is caused by the global warming and frequent extreme meteorological events, and it changes the climate feature and gradient effect of tropical rainforest ecological system.Here we focus on the tropical rainforest of Xishuangbanna, and combine the field, the meteorological and hydrological data and control experiments in sampling plot. By measuring the ecological stoichiometry ratio and geochemical elements of vegetable-wither matter-soil system samples, we will discuss the variation characteristics of the ecological stoichiometry ratio and geochemical elements in spatial and temporal scales and water thermal gradient. On these bases, we analysize and discuss the response of the ecological stoichiometry ratio and geochemical elements of dominant species in the tropical rainforest ecosystem to environmental change through multivariate statistical analysis, and try to reveal the material cycle mechanism of Xishuangbanna tropical rainforest in our country. This project can be rich and perfect the theoretical study of ecological environment changes of tropical rainforest in our country. In addition, this research results can systematically identify the response process and acclimation mechanism of forest ecosystem to global change, and it will provide certain scientific basis for effective protection and control of tropical rainforest ecological system.

全球变暖和极端气候事件的频发造成了西双版纳地区干旱程度增加，改变了热带雨林生态系统的气候特征与梯度效应。本项目以西双版纳热带季雨林与山地雨林为研究对象，结合研究区气象、水文观测资料和并结合样地条件控制试验，通过测定"植物-凋谢物-土壤"系统样品的生态化学计量比值和化学元素及相关指标，探讨热带雨林中"植物-凋谢物-土壤"系统生态化学计量比及化学元素在时空尺度上和水热梯度上的变化特征。在此基础上，利用多变量统计分析和探讨优势种植物系统生态化学计量比及化学元素对环境变化的响应，并尝试揭示我国西双版纳热带雨林物质循环机制。项目的完成可丰富和完善我国热带雨林生态环境变化研究的理论，为系统识别森林生态系统对全球变化胁迫的响应过程与适应机制，有效地对热带雨林生态系统进行保护和治理，提供一定的科学依据。

人类活动加剧对全球森林系统的影响日益剧增，热带雨林的日趋减少。近年来全球变暖和极端气候事件的频发造成了西双版纳热带雨林板块化，并改变了其陆地生态系统的气候特征与梯度效应。本文以中国面积最大的西双版纳热带雨林生态系统为研究对象，运用野外观测和室内分析方法，以土壤-植物元素生态化学计量特征新思路研究了热带雨林土壤-植被系统的“土壤-叶片-凋落叶”系统养分元素碳（C）氮（N）磷（P）及其生态化学计量特征的生物地球化学循环以及对元素循环梯度和水热梯度下的海拔高梯度效应，探讨了热带雨林系统生物地球化学循环特征及其养分元素的限制状况，揭示我国西双版纳热带雨林物质循环机制。研究结果为气候变化和人类活动双重压力胁迫下，评价热带雨林生态系统结构与功能对环境变化的响应，以及为热带雨林的有效保护和治理，提供科学依据。