Assessment Of Ecosystem Services In Huangqian Watershed Based On InVEST Model

The Huangqian River Basin is located in the soil conservation area of the low hills of southern Luzhong and the national key soil erosion control area of Yimengshan in Taishan Mountain,and is an important water source in Tai’an City.Currently,it has issues with ecology and the environment,including low soil fine grain and clay content,a basic forest structure,and inadequate stability.Therefore,it is of great significance to evaluate the ecosystem service functions such as water conservation,soil conservation,carbon storage and habitat quality for the natural protection and sustainable development of the ecosystem in Huangqian watershed.This study employed the remote sensing interpretation,field sampling,InVEST model,GIS spatial analysis and other methods to quantitatively evaluate the water conservation function,soil conservation function,carbon storage function,and habitat quality function in the Huangqian River Basin in 2020 based on fundamental data such as remote sensing,meteorological,terrain,and soil.Analyze the distribution of ecosystem services across various land use types,altitudes,slopes,and features,and study the trade-offs and synergies between the various ecosystem service activities.Screen small watersheds that require priority governance by factoring in the pattern of importance of ecological services.The main conclusions are as follows:(1)In 2020,the area proportion of different land use types in Huangqian watershed was Arbor woodland,Garden plot,Constructed,Water,Other forest land.Cultivated land,Shrubbery,Road,With 400～550 meters,>25°,and the largest distribution of sunny slope,the altitude exhibits a pattern of high north and low south,high west and low east.The 27 small watersheds range in size from 1.97 to 25.92 km~2,and the predominant land uses were Garden plot,Forest land,and Constructed,with an average altitude of 250 to 810 m and an average slope of 9 to 27°.(2)The water conservation per unit area of Huangqian watershed in 2020 was 75219.92m~3/(km~2·a),and the total water conservation was 21.9849 million m~3.The soil conservation per unit area was 121397.84 t/(km~2·a),and the total soil conservation was 3547.97 million t.The carbon storage per unit area was 10603.01 t/(km~2·a),and the total carbon storage was309.88 million t.The average habitat quality index was 0.81,which was generally better.From the perspective of land use types,the highest water conservation was cultivated land,and the highest soil conservation,carbon storage and habitat quality were arbor woodland.From the perspective of altitude,the amount of water conservation changed in a’N’shape with the increase of altitude,the amount of soil conservation increased first and then decreased with the increase of altitude,and the carbon storage and habitat quality increased with the increase of altitude.From the perspective of slope,water conservation,soil conservation and carbon storage increased with the increase of slope.The habitat quality changed in a’√’shape with the increase of slope gradient.From the aspect of slope,the water conservation was the highest in the semi-shady slope,and the soil conservation,carbon storage and habitat quality were the highest in the shady slope.(3)The trade-off and synergy relationship of four ecosystem service functions in Huangqian watershed was as follows:water conservation and soil conservation are strongly positively correlated;soil conservation was positively correlated with habitat quality services.Combining different ecosystem service functions,the normalized mean value in 2020 is 0.57.From the perspective of the spatial pattern of the importance of integrated ecosystem services,the area of heavily important areas was the largest,concentrated in the arbor forests in the western and northern parts of the basin.The extremely important areas were scattered at an altitude of more than 550 m and a slope of more than 25°.The medium important area was mainly located in the orchard,with an altitude of 250～550 m and a slope of 6°～15°.The general important areas were distributed near agricultural planting areas and urban villages with frequent human activities,with an altitude of less than 250 m and a slope of less than 6°.(4)The spatial aggregation and difference of ecosystem service functions were significant.The’HH’aggregation and hot spot areas were mainly distributed in the western and northern mountainous areas of the basin;the’LL’aggregation and cold spot areas were mainly distributed in the southern part of the basin and residential areas.(5)From the perspective of different small watersheds,7 of the 27 small watersheds were generally important,and they are selected as the priority management areas in the Huangqian watershed.Among them,No.7 and No.16 small watersheds should comprehensively improve the four types of ecosystem service functions.13 medium important small watersheds were secondary management areas.It is suggested that small-scale production and construction activities should be carried out reasonably on the basis of protecting ecological space.The seven small watersheds with heavy important grades have relatively lush vegetation and good ecosystem service functions.They should be protected in strict accordance with relevant protection systems,limit human disturbance,and maintain the status quo.