天山北坡植被净初级生产力及对气候和土地利用/覆被变化响应的模拟与实证研究

There is lack of understanding in the spatial-temporal dynamics features and impact factors of vegetation net primary productivity, especially the responses of vegetation net primary productivity to climate change and human activities in the arid and semi-arid areas, due to the significant differences in the natural environment, type, land use management, and research methods. The project, therefore, plans to investigate the effect of climate variations and land use/cover change on vegetation net primary productivity with a comprehensive process-based ecosystem model（Agro-IBIS）which is integrated with agricultural management module in the northern slope of Tianshan Mountains, where there are distinct differences in the climate and landform, vegetation types, and land use. Firstly, the model performance of simulating the vegetation net primary productivity will be validated by the ecological parameters data (e.g. biomass, leaf area index, evapotranspiration) from field observation, and improvement of the model and optimization of the vegetation phenology parameters aiming at the special geographical and ecological characteristics of the arid area. Secondly, the process model will be used to analyze the relationship between the vegetation net primary productivity and different land use/cover types as well as main climate factors based on the scenario simulations. Finally, the suggestions and countermeasures of sustainable development of the arid ecosystems will be put forward on the basis above. The study will promote the development in the field of biogeography and vegetation ecology.

由于自然环境条件、生态系统类型、土地利用管理和研究手段等方面的显著差异，对于植被净初级生产力的时空变化特征及其影响因素还缺乏明确认识，尤其是干旱半干旱地区植被净初级生产力对气候变化和人类活动的响应机制研究存在不足。因此，本项目拟选择具有显著气候和地形差异、植被类型和土地利用多样的天山北坡为研究区，基于野外观测试验，借助包括农业管理模块的综合生态系统模型（Agro-IBIS），研究气候波动和土地利用/覆被变化对植被净初级生产力的影响。首先通过生物量、叶面积指数和蒸散等生理生态指标的野外观测数据，校验模型对植被净初级生产力模拟的有效性和精度，针对干旱区特殊的地理与生态特点，发展及完善模型以及调整和优化植物物候参数；再基于模型的多情景模拟，分析植被净初级生产力与不同土地利用/覆被类型和主要环境因子之间的关系，并提出干旱区生态系统可持续发展的对策和建议。本项研究将促进植被生态学和生物地理学的发展。

本课题以新疆天山北坡为研究区，通过野外观测、遥感以及基于过程的生态系统模型（Agro-IBIS）等方法，对该研究区气候变化和土地利用/覆被变化及其对植被净初级生产力的影响过程进行了分析。首先，建立了新疆区域近40年来的不同分辨率的气候数据集，并借助天山北坡农业气象站多年气象观测和生态指标参数等时间序列数据对基于过程的新型生态系统模型（Agro-IBIS）的有效性和精度进行了验证。然后，在气候和人类活动影响的背景下，从站点到区域尺度对新疆绿洲干旱区农田生态系统净初级生产力（NPP）变化进行了时空模拟和估算。其次，通过数值模拟分析亚洲中部干旱区典型代表—新疆农田生态系统碳循环的动态及其时空格局特征，揭示了该区近 30 多年来农田生态系统碳动态过程及其对气候变化与农业集约管理的响应。通过多情景数值模拟实验，分析了1979-2009年新疆农田生态系统新疆农田生态系统碳动态对气候变化、CO2浓度升高以及农田管理的响应，提出了合理的干旱区绿洲农田利用及管理制度建议，以便促进农田生态系统的可持续f发展管理与应对气候变化提供科学依据。