鄱阳湖南矶湿地生态系统野外监测进展

Progresses of Wetland Ecosystem Field Monitoring in Nanji Wetland National Nature Reserve,South of Poyang Lake

长期以来,自然环境变化和人类活动共同影响着鄱阳湖南矶湿地生态系统,开展该生态系统的野外监测和提升监测水平十分必要。2013~2017年,江西师范大学鄱阳湖湿地与流域研究教育部重点实验室联合南矶湿地国家级自然保护区,在鄱阳湖南矶湿地野外综合试验站建设了野外监测平台,该平台主要包括一个大气通量观测系统、三个常规水质和气候监测浮体以及相应的动态监测网络系统。围绕该区典型湿地的气、土、水、生四方面的多项指标,开展了有序监测。每年共采集、分析和整理各类数据超过1 GB,大量的监测数据和信息为鄱阳湖南部湿地生态系统的长期研究和区域水生态系统健康管理提供了支撑服务。监测和研究结果表明,(1)南矶湿地作为碳汇,其CO2通量月变化受季节性淹水和气温变化双重影响,年内吸收与排放具有周期性变化特征;(2)在垂直分布方向上,在0~50 cm深度土层中,随着土壤深度增加,土壤有机碳含量所占比例急剧减小,0~15 cm深度土层的土壤有机碳含量占0~50 cm深度土层的土壤有机碳含量的50%以上,且其主要受土壤水分和植物生物量的影响,南矶湿地土壤有机碳含量也高于鄱阳湖周边区域土壤;(3)鄱阳湖湿地水体中的溶解性有机碳含量高于开阔水面,而且南矶湿地可能是鄱阳湖水体中有机碳的重要来源;(4)水位变化引起的湖泊底质变化是大型底栖动物的种群结构和多样性差异的主要驱动因素,因此,人类活动对于碟形湖水位的控制会对底栖动物结构组成产生影响。野外综合试验平台的建设和发展应该在制度建设、数据挖掘和开放合作三方面持续提升,以期为湿地管理和保护提供科技支撑。

Nanji Wetland National Nature Reserve located in the south of Poyang Lake, was suffered a series of pressure caused by natural environment changes mixed with human activities. These pressures would directly and indirectly influence the wetland ecosystem health, and then the normal supply of ecosystem service was threatened. Therefore, it is very necessary to conduct the systematic monitoring to improve the level of ecosystem field monitoring. This study concludes and summarizes the field monitoring platform of Nanji Wetland Comprehensive Experimental Station（NWCES）, which was established by the Key Laboratory of Wetland and Watershed Research, Ministry of Education, Jiangxi Normal University and the Nanji Wetland National Nature Reserve from 2013 to 2017. The NWCES now included an atmospheric flux observation platform, three Mega-Floats with the function of water quality monitoring and related dynamic monitoring grid system. The indicators related to atmosphere, soil, water and organism in the typical wetland system were monitored orderly according to national or industrial standards. More than 1 GB of various types of data were collected and analysed each year, which could provide the supporting service for the long-term research and virtuous management of regional water ecosystem health management in the south of Poyang Lake. Our results showed that：（1） the Nanji wetland ecosystem was considered carbon sinks, moreover, the monthly variation of CO2 flux in Nanji wetland was affected by seasonal flooding and temperature change, and the absorption and emission of CO2 were periodically changed in one year.（2） The ratio of soil organic carbon（SOC） distribution decreased sharply in the vertical direction, and the SOC in 0-15 cm accounted for over50% SOC in 0-50 cm soil layer, which was mainly affected by the soil moisture and plant biomass. The ratio of soil organic carbon was higher than the perimeter zone of Poyang Lake.（3） It is quite clear that water quality of dish lake in Poyang Lake was mainly affected by water level change of open water in flood period,and the dissolved organic carbon（DOC） concentration of wetland water was higher than that of open water in the Poyang lake. The Nanji wetland may be the essential source of DOC of Poyang Lake.（4） The structure and diversity of benthic macroinvertebrate fauna may be affected by sediment change which caused by water level change, therefore human activities like water level control of dish lake could directly change the structure and diversity of benthic macroinvertebrate fauna. The development of field comprehensive monitoring should be based on the continuous improvement of mechanism development, data research and opening cooperation, which is expected to offer technological support to wetland management and protection.