Ecological Health Evaluation On Poyang Lake Wetland

Wetland has important ecological,economic and social functions,which benefits human beings a lot.With the acceleration of urbanization process,the impact of human activities on wetlands is gradually increasing,and the ecological health of Poyang Lake wetland is becoming increasingly damaged.The ecological health assessment of Poyang Lake wetland will help to provide scientific basis for strengthening the ecological protection,rational planning and management in Poyang Lake wetland.After extensive literature review on wetland ecological health assessment,this paper selected the most widely used "three-level evaluation methods" in the United States to evaluate the health status of Poyang Lake wetland.Based on the evaluation results,we examined the ecological health status and the existing problems of Poyang Lake wetland,and investigated the impacts of human-related stressors on the ecological health status of Poyang Lake wetland.Finally,we presented suggestions and recommendations on the management of Poyang Lake wetland.The main contents and conclusions of the article are as follows:(1)To build a three level evaluation system of wetland ecological health in Poyang Lake,landscape development intensity(LDI)method,wetland Rapid Assessment Procedure(WRAP)method and vegetation-based indexes of biological integrity(V-IBI)method were selected to evaluate the ecological health status of Poyang Lake wetland.The land use status of Poyang Lake wetland was evaluated by LDI method.The WRAP method of Poyang Lake wetland was evaluated by a set of indicators that were reviewed by experts.The V-IBI method of the Poyang Lake wetland was developed based on extensive field surveys on wetland plant assemblages and wetland environment.(2)The results of the "three-level evaluation method" showed that the ecological health status of the Poyang Lake wetland was generally good.The ecosystem health of the two major national nature reserves in the Poyang Lake wetland were relatively higher,while the ecological health of the southeastern and southern regions were lower.The ecological health of Poyang Lake wetland showed significant spatial differentiation,which is closely related with and the type and intensity of human activities.(3)In order to valid the applicability of the three methods for assessing the ecological health of the Poyang Lake wetland,we analyzed the correlation coefficients of the results derived from the three methods,and found that they were highly correlated.There is a significant negative correlation between V-IBI and LDI(r =-0.4,p <0.05),a significant positive correlation between V-IBI and WRAP(r = 0.63,p <0.01),and a significant negative correlation between WRAP and LDI(r =-0.4,p <0.01).This confirms that the three-level evaluation method has good suitability in Poyang Lake wetland ecological health evaluation.(4)This paper analyzed the relationship between the ecological health of Poyang Lake wetland and human-related stressors.The results showed that the contents of DTP,DTN,NO2-N and Chl a had significant correlations with wetland ecological health.In addition,the distances to the rural residential area,county road,farmlands and the mining and industry lands were negatively correlated with the ecological health status of Poyang Lake wetland.The impacts of human activities on wetland health decayed with the increase of spatial distances.(5)This study provides an indicator framework for comprehensively assessing the ecological health of Poyang Lake wetland.The identification of the key influencing factors on wetland health status should be important for the protection and management of Poyang Lake wetland.