Assessment Of The Ecological Service Value Variation And Analysis Of The Driving Power In Small Sanjiang Plain

Wetland,as an alternate system of land and water,is one of the most important ecosystems on earth.Ecosystem services represent the benefits that humans get directly or indirectly from ecosystem functions.On the one hand,in recent decades,the ecosystem has been getting worse and worse to the point of serious damage.The recognition of the value of ecosystem services,which used to exist mainly in the intellectual circle,is now gradually recognized by the public and has begun to influence social decision-making to some extent.On the other hand,the natural environment increasingly affects social and economic activities and human life.Human’s demand and dependence on the resources,purification capacity,comfort and life support system provided by the ecosystem affect human activities.The ecological service value of wetland is far greater than its direct economic value.The study area in this paper was selected as the typical small Sanjiang Plain,where wetland was eroded by arable land during the study period.This paper collected multiperiod Landsat images and other remote sensing data from 1984 to 2020,applied geographical technologies such as RS and GIS,combined with basic geography,statistical data and other multi-source data sources,and referred to the Conceptual framework of the United Nations Millennium Ecosystem Assessment（MA）.The ecological service function can be divided into 7 subcategories,such as water conservation.With RS,GIS and other geological technology based on analysis results of wetland area,through the market value method,replacement cost method and so on the many kinds of evaluation method to evaluate its value,its space-time distribution rule,research through exploring areas of different ecological service function value,evaluated the ecological services value of currency in the sense of relative importance,It provides a new idea and method for wetland ecological service value evaluation.This paper draws the following conclusions:（1）In the past 36 years（1984-2020）,the land use type in the study area changed dramatically from marsh wetland（45.19%）to agricultural arable land（78.54%）,and most of the agricultural arable land changed from marsh wetland.The landscape pattern indexes CA,NP,PD and LSI of wetland decreased year by year.This indicates that the area of wetland not only shrank sharply,but also became increasingly fragmented.The wetland shrank the fastest during 1992-2005,with an average annual shrinking rate of5.45%,and agricultural activities were most intense during this period.（2）From 1984 to 2020,the value of wetland ecological services in small Sanjiang Plain showed a trend of continuous decline year by year.From 1992 to 2005,the value of wetland ecological services declined most rapidly,with a decrease rate of 46.6% and an average annual decrease of 3.6%.Among the ecological service values,the proportion of flood storage was the highest.The proportion of climate regulation is the lowest,and the proportion is flood storage > habitat > entertainment > carbon fixation and oxygen release > water conservation > scientific research > climate regulation.The proportion of climate regulation is the lowest,but it has irreplaceable effect.Combined with the analysis of social data and remote sensing interpretation data,the fundamental driving force for the change of ecological service value of small Sanjiang river is the development of agricultural economy,which leads to a series of human factors such as the overexpansion of agricultural areas,the disorderly development of towns,and the discharge of production and domestic sewage.（3）During 1984-1992,the average annual economic growth rate was the highest（14.7%）,and the average annual consumption of wetland ecological service value was only 0.15%,but the lowest,indicating that economic development is not directly proportional to the consumption of ecosystem,and there is no necessary connection between the two.Economic development does not necessarily need to sacrifice environmental resources.It demonstrates the significance and theoretical support of sustainable development.Small Sanjiang Plain used to be the largest marsh wetland in China.Due to the rapid expansion of agricultural activities in recent years,the wetland in small Sanjiang Plain has undergone drastic changes and is one of the most typical areas eroded by arable land in a short period of time.While obtaining the direct economic benefits of agricultural development,the potential loss of ecological service value of wetland is often ignored.The ecological service index which best reflects the ecological function of regional wetland is selected to scientifically quantify the ecological service value of small wetland in Sanjiang Plain,and reveal the profound influence mechanism of agricultural activities and economic development on wetland natural capital.This study fully introduces and evaluates the value of wetland ecological services,and also provides effective support for the coordinated and sustainable development of society,nature and economy and the formulation of scientific ecological policies.