Evaluation And Monitoring Of Zoige Plateau Wetland Ecosystem Based On Remote Sensing Technology

The Zoige Plateau wetland is the largest plateau wetland in China,and the largest peat marsh in the world.There are many endemic and endangered species inhabiting the Zoige Plateau wetland,which is of great economic and ecological significance.However,the Zoige Plateau wetland is undergoing degradation.Its ecological functions are losing,and the species habitats are threatened.It is therefore imperative to study Zoige Plateau wetland,especially to study its overall evaluation and monitoring management.The objectives of this study are to analyze current changes in ecosystem of the Zoige Plateau wetland and their causes,and to establish a wetland monitoring and management method.In this study,the dynamics of land use and ecosystem services value are analyzed and causes and recovery mechanisms of ecosystem services value changes are discussed based on field survey and remote sensing data of the vegetation community and soil carbon content of Zoige Plateau wetland in 2013,2014and 2016.Meanwhile,the average biomass of wetland vegetation and soil carbon content were fitted with remote sensing factors.The results of this study were the following:(1)The total ecosystem service values in 2013,2014 and 2016 were 64.6,635 and62.4 billion yuan,respectively.Sensitivity analysis showed that the results were reliable.Wetland accounted for about 50%of the total value and was the major part of the ecosystem services value.The primary cause of the decline in ecosystem service value in this region is the reduction of wetland area.Meanwhile,the rising trend of the biodiversity index during the study period is due to the more uniform species distribution.(2)The area of grassland,wetland and lake have all declined.The decline of lakes was the largest.The area of forests increased after a slight decline,and the area of bare land has been rising all the time,indicating the degradation of ecosystems.The trend was that:lake degenerate into wetland,wetlands degenerate into grassland or bare land,and forest and grassland degenerate directly or indirectly into bare land.(3)Wetland vegetation biomass has a highly significant correlation with seven remote sensing factors that included Normalized Vegetation Index(NDVI),Principal Component Analysis 2(PC2),Band 1(B1),B3,B4,Brightness and latitude(P<0.01),and a significant correlation with five remote sensing factors that included B7,Greenness,Ratio Vegetation Index(RVI),Enhanced Vegetation Index(EVI)and PC3.Other factors had no significant correlation with wetland vegetation biomass.(4)The regression fitting effect of wetland vegetation biomass and remote sensing factors was well.The regression coefficient R~2 of the regression equation is 0.907.The calculated value of average wetland vegetation biomass in 2013,2014 and 2016 were1562.96,1635.51 and 1565.77 g/m~2,respectively.The order of community biomass of different vegetation types is:emerged plant>submerged plants≈floating leaf plants>floating plants(5)Soil carbon content has a highly significant correlation with longitude and latitude(P<0.01),and a significant correation with Greenness and PC1(P<0.05).In addition,the regression coefficient of PC1’s eighth-order Gauss function was the biggest,which was 0.716.(6)The surface carbon content of soil in Zoige Plateau wetland was about 58.29g/kg,which was higher than that in other areas,indicating that the Zoige Plateau wetland has strong carbon sink capacity.