| Shibing Karst world natural heritage site has an extremely important outstanding universal value(OUV).Due to its fragile karst ecological environment and unreasonable land use by humans,the rate of soil loss is greater than the rate of soil formation(Soil Loss Tolerance),leading to soil erosion.At the same time,the comprehensive pressure from population,environment,social economy and other aspects has increased the difficulty of maintaining and sustainable development of the ecological security of the heritage site.Moreover,Shibing Karst is dolomite karst landform,and at this stage,the soil erosion research in the dolomite karst area is relatively lacking.The current soil loss tolerance for the entire karst area has brought many difficulties to the assessment and prevention of soil erosion and rocky desertification in the dolomite area.Therefore,it is of great practical and theoretical significance to apply soil erosion and ecological safety evaluation in Shibing Karst and buffer zone,and apply the research results to the ecological security regulation of heritage property and buffer zone.The paper takes Shibing Karst World Natural Heritage and its buffer zone as the study area,through literature analysis,field monitoring sampling and experimental analysis,to explore the impact of human activities on soil nutrients,calculate the rate of soil formation,and analyze the degree of soil erosion and its spatial distribution characteristics in the property and buffer zone.Using the Delphi and AHP method,the ecological-safety evaluation index system and evaluation model are constructed by means of the PSR model,and the ecological security status of the heritage site and the buffer zone socio-economic,population,environment,soil erosion and other factors are evaluated.Finally,countermeasures are proposed for the ecological security regulation of the heritage site and buffer zone.The main findings are as follows:Shibing Karst was chosen as the study area,methods including literature analysis,field monitoring sampling and laboratory analysis were used to explore the effects of human activities on soil nutrients,calculate the rate of soil formation in heritage sites,and analyze soil erosion characteristics.Delphi method,AHP method,PSR model is used to construct the indicator ecological security evaluation index system and evaluation model.And the ecological security status of the heritage site is evaluated by comprehensive socio-economic,population,environment,soil erosion and other factors.Finally,countermeasures for the ecological security regulation of the heritage site are proposed.The main findings are as follows:(1)The contents of organic carbon,total nitrogen,alkaline hydrolysable nitrogen,and available potassium as well as the pH of the soil in dolomite shrubland were higher than those in limestone shrubland.The total potassium,total phosphorus,and available phosphorus contents of soil in limestone shrubland were higher than those in dolomite shrubland.Among the four types of land use most strongly affected by human activities(paddy field,dryland,flue-cured tobacco field,and pear orchard),the nutrient contents(except potassium in the upper soil layer)were higher than those in the lower layer.The differences in nutrient contents between upper and lower layers were relatively small in the dryland and the pear orchard,whereas they were large for the paddy field and flue-cured tobacco field.Among the land-use types in the property,the dolomite shrubland had the best soil quality,while the flue-cured tobacco field had the worst.Of the four types of land use most strongly affected by human activities,pear orchard had the best soil quality.(2)The soil formation rate of the dolomite basin is calculated to be 32.94 t/km~2·a.Its value is less than the soil loss tolerance of soil in the current karst area of China(50t/km2·a).Therefore,it is necessary to control the rate of soil erosion below the rate of soil formation,and at the same time control the loss of soil nutrients,then,soil erosion will be prevented.(3)The area of soil erosion in the heritage site and buffer zone in 2017 was 176.53 km~2,of which the soil erosion area of the heritage site was 61.33 km~2,accounting for 34.7%of the total erosion area.Mild,moderate erosion is the main level of erosion in heritage sites and buffer zones.The proportion of strong and extremely strong erosion decreased in turn,and the proportion of severe erosion was small.It shows that the ecological condition of the heritage site and the buffer zone is relatively good,and the soil erosion is relatively light.Therefore,the treatment of light and moderate soil erosion is of great significance to the reduction of total soil erosion in heritage sites and buffer zones.From the perspective of spatial distribution,the soil erosion in the buffer zone of the heritage site is more serious than that in the core zone.The degree of soil erosion in the buffer zone and core zone is between mild to strong.The erosion of the Shiqiao,Longjing,Tangtou and Chayuan areas in the northern part of the heritage site is relatively strong.Therefore,the treatment of soil erosion in the upper reaches of the heritage site and the whole buffer zone has important practical significance for the ecological security maintenance of the heritage site.The slightest erosion of the garden and forested land is the most serious,the strong erosion of the dryland is the most serious,and the moderate erosion of the shrub forest and grassland is the most serious.It indicates that man-made farming activities have serious damage to the soil.Garden land and forest land play an important role in alleviating mild soil erosion.Shrubbery and grassland have a significant effect on reducing moderate soil erosion.(4)Based on the analysis of the social,economic and natural environment of Shibing Karst,AHP is used to construct the ecological security evaluation index system of the heritage site and its buffer zone.The comprehensive judgment matrix is constructed by the Duffel method,and the relative weights of the compared elements are calculated by the judgment matrix using the square root method.The evaluation indicators are standardized,and then the ecological security degree of the heritage site and buffer zone is calculated.The results showed that the ecological security degree between 2010 and 2012 were 0.477,0.430 and 0.551,respectively,indicating that the ecological security level was low and in a critical safe state.The ecological security degree between 2013 and 2016 were 0.684,0.686,0.743 and 0.602,respectively,improved and in a safer state.In 2010-2016,overall,the ecological safety degree of Shibing Karst showed a trend of continuous improvement.(5)According to the weight of index indicators of ecological security evaluation of heritage site and buffer zone,and the status of ecological security of heritage sites,ecological regulation measures has been proposed from six aspects:increasing vegetation coverage,pollutant treatment and control,social and economic development,heritage site protection,tourism personnel training,and scientific research.Specifically,it includes:adjusting land use types,controlling soil loss,restoring vegetation,improving pollutant treatment facilities,guiding and regulating local people’s production and living behaviors,monitoring pollutants,controlling pollutant discharge,adjusting agricultural industrial structure,tapping national cultural characteristics,Partitioning protect heritage site and buffer zone,establishing full-time institutions,speeding up legislation,training of tourism talents,and strengthening scientific research. |
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