Landscape Pattern Analysis And Ecological Benefit Evaluation Of Land Use In Chishui City

Chishui City,as an important ecological barrier in the upper reaches of the Yangtze River,is one of the ten largest bamboo townships in China.To grasp the spatial and temporal characteristics of land use landscape pattern and ecosystem service value can provide reference for sustainable land use and ecological environment protection.Based on the Landsat remote sensing images of Chishui City in Guizhou Province in 1999,2005,2011 and 2016,this study used 3S technology to extract and analyze the land use and landscape pattern information of Chishui City,and combined qualitative analysis with quantitative analysis to explore the driving factors of land use landscape pattern change in the study area.Based on the principles of eco-economics,this study applied the Landsat remote sensing images to Chishui City in1999,2005,2011 and 2016.Dynamic assessment of ecosystem service value.The results show that:(1)Land use change analysis.In 1999,2005,2010 and 2016,the overall accuracy and Kappa coefficient of remote sensing image classification reached 88% and 0.86 respectively,and the classification results were good.Based on the classification results of remote sensing images,the land use change in Chishui City was analyzed.During the period of 1992-2016,the area of woodland,water area,construction land and grassland increased year by year,with the largest proportion of woodland area reaching more than 70%.The total amount of change was190.11 km2,second only to cultivated land,and the area of construction land changed most significantly.The area was reduced by 216.35 km2 and 0.78 km2,respectively,and mainly transferred to forest land,construction land and water area.The comprehensive index of land use degree shows a downward trend,which indicates that the overall land use in Chishui City tends to be stable.(2)Analysis of landscape pattern change.At the patch level,forest land has been the dominant landscape type in the study area since 1999-2016.The total number of patches in the study area has increased year by year,totally 875.The overall fragmentation of landscape pattern has been aggravated.The reason is that the number of cultivated land patches has increased greatly with the implementation of the project of converting farmland to forestry.The fractal dimension of each landscape type has little change and the patch shape is relatively simple.Patch shape index showed a downward trend,indicating that patch characteristics of forest land and construction land evolved in a regular direction,and human intervention was more obvious;in addition to unused land,the dispersion index of other landscape types showed a downward trend,and space was more aggregated;the largest patch index of forest land showed an upward trend,and the largest patch index of cultivated land showed a downward trend,reflecting the dominant landscape types in the study area.The influence of type forest land on the whole landscape is more and more extensive.On the landscape level,the separationindex,diversity index and evenness index showed a downward trend,while the spread index showed an upward trend.The main reason was that the area of forest land was further expanded,the dominant landscape type forest land had more control over the overall landscape,and the spatial connectivity of each landscape type was enhanced.(3)Driving factors analysis.Qualitative analysis results show that population factors,economic development,industrial structure and policy factors have a certain degree of impact on land use landscape change in the study area.Through principal component analysis,it can be seen that there are two main driving factors affecting land use landscape pattern change in Chishui City: socio-economic development and agricultural production,namely,gross domestic product and food production.(4)Value analysis of ecosystem services.The total value of ecosystem services in the study area increased from 46.4175 million yuan to 50.4642 million yuan in 1999-2016.Among them,the service value of forest land and cultivated land contributes more than 90% to the total value,the ecosystem service value of forest land is the largest and increases year by year,and the ecosystem service value of cultivated land is decreasing,which decreases by 2.0894 million yuan.In terms of the value of ecosystem services,in the past 17 years,the total value of other ecosystem services increased except for the service value of waste gas treatment and food production.Soil formation and protection,water conservation and gas regulation ranked the top three.As far as ecosystem service types are concerned,the value components of ecosystem service types have remained stable in different periods,and the value components of regulating service and supporting service types are more than 80% in total.Sensitivity analysis showed that except in 1999,the value of ecosystem services of forest land was more sensitive to the value coefficient,the sensitivity coefficients of different types in other periods were less than 1,and the results of ecosystem services evaluation were more credible.