The Characteristics And Ecosystem Services' Comprehensive Performance Evaluation Of Urban Mountain Natural Remnants In Karst Area

Guiyang is a mountainous city dominated by karst landforms,the surrounding natural mountains are gradually surrounded into the city by urban construction in the process of urbanization,forming a typical urban landscape pattern of mountain inlay.These Urban Mountain Natural Remnants,partially or completely isolated by the urban artificial environment,have become the core of the urban natural system,play a variety of irreplaceable ecological service functions,and are the unique latecomer resource advantages of mountain cities.However,due to the lack of relevant basic research,in the process of rapid urbanization construction in recent years,the natural remains of urban mountain bodies have not been scientifically recognized and paid enough attention to,blind exploitation and utilization,encroachment and destruction,even cutting mountains and building cities,and other negative phenomena are common,leading to the decline of urban Karst mountain vegetation and the intensification of ecological damage.Based on this,This study selected Guiyang built-up area in 2018 as the main research area,combined with landscape architecture,urban landscape ecology,urban and rural planning and management,environmental resources science,social economics and other related theories,,using 3S technology as the platform,comprehensive use of Spatial Analysis,Field Aurvey,Meta Analysis,Analytic Hierarchy Process and Atatistical Analysis method,literature collection and induction method,fieldinvestigation method,analytic hierarchy process and unified.By means of qualitative and quantitative analysis,the Characteristics and Ecosystem Services' Comprehensive Performance Evaluation of Urban Mountain Natural Remnants in Karst area are analyzed and studied.The main findings are as follows:(1)The landscape pattern of Urban Mountain Natural Remnants is characterized by a total of527 patches,with a total area of 4493.09 hm2,type area accounting for 12.20%,landscape shape index is 30.39,mean nearest distance is 162.80 m,connectivity index is 0.62,aggregation index is95.61,separation index is 5592.76;The scale morphological characteristics showed that the average patch area is 8.53 hm2,the range difference is 354.01 hm2,the number of mountains with vertical projection area of 1-3 hm2 is 31.12%,the average patch shape index is 1.47,the range difference is 1.65,the number of mountains with patch shape index of 1.20-1.40 is 40.23%.the average relative height is 31.21 m,the relative height of the mountain body with of 258 m,22.39%is 16-20 m;the average slope is 12.92%,the range is 36.07%,and the number of mountains with an average slope of 8.00%-11.00% is 28.08%;The vegetation cover is characterized by three types of cover: coniferous and broad-leaved mixed forest,shrub and bare land.the landscape advantage of woodland is obvious.the average canopy cover accounting for 0.74,the range difference is 0.78,and the number of mountains with canopy cover ratio 0.70-0.90 is 52.75%;The spatial distribution is characterized by obvious aggregation distribution,mainly zonal distribution in Baihua Mountains,Qianling Mountains and Nanyue Mountains;the distance from the road is small,the space accessibility is better in traffic distance,the regional road density is low,and the space accessibility is poor in traffic volume;the population density in buffer zone is uneven,and the number of mountains with population density of 5000-8000 in the buffer zone is 18.22%;The highest positive correlation between patch area and relative height(0.692),the highest negative correlation with road density(-0.199),the highest positive correlation between relative height and mean slope(0.732),the highest positive correlation between patch shape and mean slope(0.475),the highest positive correlation between regional road density and population density in buffer zone(0.184),the highest negative correlation with mean slope(-0.215),and the highest positive correlation between population density in buffer zone and canopy ratio(0.345)and negative correlation with mean slope(-0.101).(2)The evaluation of Ecosystem Services of Urban Mountain Natural Remnants is mainly composed of 3 kinds and 8 indexes,and the weight distribution of evaluation indexes is counted from different perspectives.The ranking of index weight from theoretical perspective is as follows:Carbon Fixation and Oxygen Release > Depollution of Environment >Habitat > Soil Conservation > Climate Regulation > Hydrological Regulation > Aesthetic Value > Maintain Nutrient Cycling;The ranking of weights from expert perspective is: Habitat > Carbon Fixation and Oxygen Release > Aesthetic Value > Climate Regulation > Depollution of Environment >Hydrological Regulation > Soil Conservation > Maintain Nutrient Cycling;The ranking of index weight from public perspective is: Carbon Fixation and Oxygen Release > Habitat > Soil Conservation > Climate Regulation > Aesthetic Value > Depollution of Environment >Hydrological Regulation > Maintain Nutrient Cycling.The important evaluation indexes of Carbon Fixation and Oxygen Release and Habitat weight are higher than the top three.Hydrological Regulation and Maintain Nutrient Cycling weight are ranked in the last three,while the important evaluation is lower.Lastly,a comprehensive evaluation index system of theory,experts and the public is constructed,and the ranking of index weight from comprehensive angle isas follows: Habitat > Carbon Fixation and Oxygen Release > Climate Regulation > Aesthetic Value > Depollution of Environment > Hydrological Regulation > Soil Conservation > Maintain Nutrient Cycling,and the identification of Urban Mountain Natural Remnants Habitat(0.1605),Carbon Fixation and Oxygen Release(0.1472),Climate Regulation(0.1304),Aesthetic Value(0.1241)are more important.(3)The comprehensive performance of Ecosystem Services of Urban Mountain Natural Remnants in Guiyang reached 1.1291487 billion/a,and the value and proportion of 8 Ecosystem Services are as follows: Habitat 111.8424 million/a,9.91%;Soil Conservation 123.0451 million/a,10.9%;Maintain Nutrient Cycling 9.4203 million/a,0.21%;Carbon Fixation and Oxygen Release 101.0854 million/a,8.95%;Climate Regulation 295.8437 million/a,26.20%;Depollution of Environment 86.1259 million/a,7.63%;Hydrological Regulation 159.3701 million/a,14.11%;Aesthetic Value 242.4158 million/a,21.47%.The highest value of ecological services is Climate Regulation,the second is Aesthetic Value,the lowest is to Maintain Nutrient Cycling;there is a certain deviation between the importance of evaluation indicators and their actual service benefits,the deviation of Habitat ? Carbon Fixation and Oxygen Release index weight is higher,service value is lower and Aesthetic Value?Hydrological Regulation index weight is lower,service value is higher performance are the most obvious;Urban Mountain Natural Remnants Ecosystem Services value and various special characteristics the total value of Ecosystem Services showed the highest positive correlation with patch area(0.989),the highest negative correlation with regional road density(-0.177),the highest positive correlation with population density in buffer zone(0.687)and the highest negative correlation with mountain average slope(-0.370).This study can further improve the public's cognition and attention to the Urban Mountain Natural Remnants,provide theoretical support and scientific guidance for promoting their rational planning and effective management,and also help to enrich the research contents of Ecosystem Services of urban green space system,and provide important basis and foundation for urban ecological civilization construction,urban land and space planning,ecological space function zoning,ecological environment protection and ecological compensation decision.