复杂环境下西江流域社会-生态系统变化及其生态风险模拟研究

Complexity of the process mechanism and ecological risk of the river basin is one of key fundamental issues of man- land relationship. As the national strategy of Pearl River-Xijiang River economic zone come into effect, it is urgent to explore and understand the dilemma of economic development and ecological harmony on the watershed scale, especially the coupling relationship between social ecological system (SES) and ecological risk assessment (ERA) under the complex environment of mutual driving mechanism among climate change, human activities and hydrological process. However, there exists shortage of research about SES-ERA theory, technical methods and empirical study in this river basin. Hence, this project will take ERA in the Xijiang River drainage basin as the object of research based on the SES. Four scientific themes will be focused on in the project. Firstly, we will explore and investigate the theoretical framework and complex coupling mechanism between SES and ERA based on the multidisciplinary approach, and establish drainage basin ecological risk assessment and sustainability evaluation system. Secondly, reveal the change process of the key elements of SES based on water- earth- air- born change model. Thirdly, this study will assess the integrated ecological risk with a DPSIR indicator system under following the line of multiple pressures- receptor- effect coupling. At last, we simulate and predicte ERA based on CESM model in the Xijiang River. These researches will not only improve the scientific understanding but also support policy making for planning and managing ecological protection, countermeasure of risk prevention.

随着珠江-西江经济带纳入到国家发展战略中，破解流域经济发展与生态环境和谐问题研究成为更加紧迫的重要任务，流域过程机制复杂性及其生态风险研究已成为地学热点命题。然而，西江流域社会-生态系统变化机制与生态风险研究几乎空白。因此，本文拟基于复杂性思维和人水和谐理念，综合运用监测分析、3S 技术、试验分析、模型分析和系统模拟等多学科交叉研究方法，对西江流域社会-生态系统动态监测-耦合机制-生态风险-情景模拟进行集成研究。主要包括四个方面的内容：流域社会-生态系统变化和生态风险评价等理论方法探讨；基于水-土-气-生-人耦合的西江流域社会-生态系统关键要素变化过程及机制揭示；基于D-P-S-I-R 模式的西江流域生态风险评价；基于CESM 模型的西江流域生态风险监测、模拟与防范对策等研究。本研究将探索流域社会-生态系统变化及其框架下的区域生态风险评估，可以为制定流域生态保护、规划与风险对策提供科技支撑

西江流域贯通珠江-西江经济带陆海丝绸之路的重要通道，也是广西粮食主产区和珠江流域重要的生态屏障。在经济高速发展，人口不断扩张的现实下，对自然环境进行盲目和过度地开发导致流域生态系统受到强烈的外界胁迫与压力。导致流域内水环境恶化，洪涝、干旱等自然灾害频发，植被覆盖度降低，水土流失加重，生物多样性降低，流域的人地矛盾不断凸显，生态风险系数加大。随着珠江-西江经济带建设成为国家重大发展战略，广西西江流域逐渐成为西南、中南地区开放发展新的战略支撑，成为“流域生态文明建设试验区”，西江流域健康可持续发展变得尤为重要。本项目研究从流域变化分析出发，充分考虑了流域社会-生态系统组成要素以及水-土-气-生-人等影响因素，以流域社会-生态系统及其演变机制—生态风险指标体系—生态风险评价—情景风险模拟为主线，构建和探讨了流域生态系统变化与生态风险评价的理论框架与研究方法。根据社会生态系统属性及其机制，基于水-土-气-生-人耦合模型开展西江流域社会-生态系统关键要素及影响因素监测与数据集成、指标遴选和模型构建，定量分析西江流域社会-生态系统变化过程。以驱动力-压力-状态-影响-响应（DPSIR 模型）分析和构建流域生态系统风险指标体系，并在遥感和 GIS 平台下，分析生态风险的要素关联与传导性、时空异质性，揭示了西江流域社会-生态系统风险评价及空间变化规律及主要影响因素。在识别西江流域关键带社会-生态系统结构和功能基础上，建立流域关键带监测站，开展西江流域生态环境综合监测，分析土壤流失、污染迁移和植物丧失等西江流域关键带物理、化学和生物过程与格局；并在此基础上，利用 CESM 模型模拟分析未来不同情境下西江流域生态风险变化状况，为构建西江流域生态风险防范对策与生态安全体系提供科学咨询和基础数据。