鄱阳湖湿地生物完整性指数（IBI）生态健康评价研究

The assessment of ecosystem health is important for acquiring the status of wetland health, understanding the impact of human activities on wetlands, and implementing an ecological prewarning. As far as we know, the ecological health of Poyang Lake wetland has never been systematically evaluated, and an effective evaluating system is still needed. The Index of Biotic Integrity (IBI) is considered as the most powerful tool for detecting systematic impacts of environment on ecosystems based on characteristics of biological communities, and has been widely used for assessing wetland ecosystem health in many countries. In this study, we aim to develop a vegetation-based IBI (V-IBI) and beneath invertebrate-based IBI (B-IBI) for Poyang Lake wetland by utilizing field-collected data of plant community, water and soil properties, and land use. Based on the newly developed IBIs, we assess the ecological health of Poyang Lake wetland. This study will provide an important tool for implementing a long-term monitoring on the ecological health and environment quality of Poyang Lake wetland, and will contribute to the decision-making on the management and protection of the wetland by providing solid scientific basis. Our study will also represent a good example of ecosystem health assessment for other lake wetlands in China.

湿地生态健康评价对于掌握湿地的健康状况、理解人类活动干扰对其影响及实施生态预警等有重要意义。鄱阳湖湿地对于维持其流域甚至长江中下游的生态平衡十分重要，目前尚未建立其生态健康评价指标体系。生物完整性指数（Index of Biotic Integrity, IBI）是国际广泛采用的湿地健康评价方法，其评价结果较准确可靠。本项目采集生物、水体、土壤环境和土地利用等方面的数据，考虑湿地环境年际变化和水位季节性波动，构建鄱阳湖湿地的植被完整性指数（V-IBI）和底栖无脊椎动物完整性指数（B-IBI），前者综合反映湿地各方面环境变化，后者对局域生境质量更敏感；基于V-IBI和B-IBI指数，系统评价鄱阳湖湿地的生态健康状况。本研究为鄱阳湖湿地长期的生态监测提供重要方法和手段，在完善IBI指数构建方法方面有所贡献和突破，研究结果也为鄱阳湖湿地的保护管理决策提供科学依据。

本研究通过连续3年的野外调查采样，获取鄱阳湖湿地的生物群落数据及水、沉积物环境数据，构建了鄱阳湖湿地的植被完整性指数（vegetation-based index of biotic integrity, V-IBI）和底栖无脊椎动物完整性指数（benthic macroinvertebrate-based index of biotic integrity, B-IBI），系统评价了鄱阳湖湿地不同区域的生态健康状况，并采用云模型评价了鄱阳湖湿地水体富营养化状况，分析了水质与土地利用方式之间的关系。V-IBI评价结果显示，鄱阳湖湿地处于良好的生态健康状态，而B-IBI评价结果则认为鄱阳湖湿地健康状况一般，这可能是由于底栖动物生活在水底，与沉积物直接接触，且世代周期短，对水质变化及沉积物中的污染物更加敏感，能够较好地反映湿地所受干扰和胁迫的累积效应。自然保护区内的湿地生态健康状况最好，河口湿地的健康状况最差，表明河流带来的污染物对鄱阳湖湿地的生态健康有重要影响。云模型评价结果显示鄱阳湖周边湿地水体总体上处于轻度富营养化状态，主要的污染物为氮、磷。1km以内的土地利用方式对于湿地水质有重要影响，表明控制小尺度（≤1km）的土地利用格局、特别是居民用地和耕地的面积占比及河流污染物输入对于鄱阳湖湿地的保护十分重要。本研究为鄱阳湖湿地的生态健康评估和生物多样性监测提供重要的方法，也为在长江中下游其它季节性吞吐型湖泊开展生态健康评价研究提供方法上的借鉴。