Spatial And Temporal Variations Of Ecosystem Service Value In Haze Absorption By Ecological Land

The rapid development of industrialization and urbanization has made haze increasingly serious in the urban agglomeration around HangzhouBay(UAHB).Based on the relationship between "Land Use-Air Pollution",the construction land of human activities is the "source"landscape of haze,and the ecological land with haze absorption and degradation function is the"sink" landscape of haze.Under the premise of economic development and environmental protection in parallel,in addition to limiting the discharge of pollutants and dredge the city air duct,haze control need to find a more appropriate land use and more scientific ecological landscape configuration.In recent years,due to the rapid industrialization and urbanization of UAHB,conflicts between construction land and ecological land are increasing seriously.Based on the relationship between "Land Use-Ecosystem Services",changes in the number,type and spatial pattern of ecological land in UAHB will affect the ability of haze absorption and degradation.Therefore,it is important to analyze the coupling relationship between ecological land use pattern,haze absorption and degradation ability at multi-scale,which is of great significance for the selection of ecological land use scale and the optimization of green GDP,haze control and ecological civilization construction.In this study,Landsat TM/ETM remote sensing images were used as data sources in 1990,2000,2008 and 2013.The cultivated land,forest land and grass land were extracted as ecological land,and the landscape pattern was analyzed;The difference of the absorption and degradation ability of the air pollutants in the ecological land at different stages of urbanization development is taken as the means and tools of ecological service value(ESV)and space-time pattern of the haze to absorb the haze;At the same time,the paper discusses the relationship between the ecological landscape pattern index and the value of the haze ecosystem,and puts forward the strategy of raising the scale of the ecological land use planning and the improvement of the haze control effect.The results showed that:?The landscape and type of ecological land were increased by human activities,the area decreased,the fragmentation increased,the shape was complicated,the diversity level decreased,the edge effect was significant,the ecosystem function was degraded;?The ESV of haze,SO2,NOx and dust retention decreased by 0.9%,3.1%,7.6%and 0.7%.From the view of changes in the number and spatial distribution of the ESV of haze absorption,space of the haze "source-sink" is dislocation,the grade mass distribution is much more than that of strip-like and scatter-like,and shows obviously gradient evolution characteristics in the different directions.The change in the number of grade exhibits a significant attenuation from high to low;?The total ESV of haze absorption,the ESV of individual pollutants have significant spatial autocorrelation.The space gathering of total ESV of haze absorption,the ESV of NOx absorption and dust retention distribute discretely or equally.The ESV of SO2 distribute intensified.The results of local spatial autocorrelation analysis show that the total ESV of haze and the ESV of individual pollutants show different internal effects and edge effects;?In general,the positive correlation coefficients between TLA,NP,LP,PSC and the total ESV of haze,the value of individual pollutants increase with the increase of scale,but they are negatively correlated with PD and have uncertainties on individual scales.The correlation between the total ESV of haze,the ESV of individual pollutants and other landscape pattern index is more complex and uncertain.The negative effect caused by human activities on haze absorption in the ecological land is the lowest at a large scale.The management of ecological land for the purpose of haze control should be carried out at 16 km scale;?In order to control haze,ecological landscape pattern optimization may be from the following aspects:First,to maintain the ecological land area,increasing ecological land type,full use of the spatial distribution sporadic ecological land,forming a plurality of types and sizes mosaic patches evenly distributed pattern.Second,strengthen the field shelter forest and ecological corridor construction,reduce the negative effect caused by the edge of urban construction land on the capacity of haze absorption.Third,pay attention to the role of cultivated land "N sink" and improve the biodiversity of cultivated land.