| The change of landscape pattern has an important influence on the material and energy flows and the change of ecological environment.Therefore,it is very important to discuss the distribution of landscape pattern in rocky desertification area for the development of rocky desertification.In this study,diversity and complexity of remote sensing image data were used to extract the bare rock information in rocky desertification area,and by different methods including supervised classification and objectoriented classification,and the distribution characteristics of bare rock under different image resolutions were obtained.The bare rock rate distribution map of Puding County was obtained.The UAV images were used to compare two different remote sensing image data to verify the accuracy of the calculation results.The results show that sentinel-2A directly calculates the normalized rock index in the extraction of bare rock rate.Rocky desertification is also a dynamic land degradation process,which is a comprehensive reflection of difference factors,bare rock rate plays an important role in these factors.Exposed bedrock is key indicator of karst rocky desertification.Spatial distribution of rock under bare rock ratio(11%,20%,29%and 48%)is studied by analyzing the rock distribution characteristics of rocky desertification areas in Guizhou Province.The existing supervised and unsupervised classification methods based on pixels cannot meet the requirements of extraction accuracy of rocky desertification information in karst rocky desertification area under complex geological environment.So the optimal classification method is selected to classify the UAV image of rocky desertification.The result shows that the object-oriented classification has higher accuracy,it can reduce the "salt and pepper phenomenon" caused by complicated topography.Using Object-oriented Classification in remote sensing images,the UAV image is interpreted,and then the distribution characteristics of rock patches under different bare rock rates are obtained by combining the method of landscape ecology.The bare rock rate is 11%,20%,29% and48%,respectively,the average patch area of rock is negatively correlated with the bare rock rate.By studying the influence of landscape patch index,landscape shape index and landscape fragmentation index on the landscape distribution of different bare rock rates,it shows that with the increase of bare rock rates in different rocky desertification areas.The number of patches gradually increase rock shape index and rock fragmentation index gradually increase,and then the degree of rocky desertification becomes more serious.The exposed bare rock in karst area shows different distribution patterns and patch characteristics under different rocky desertification conditions.The higher the rate of bare rock is,the higher the degree of rock fragmentation is,and the distribution of patches is relatively scattered.Therefore,through the analysis of rock morphology in rocky desertification area,it can provide services for the evaluation and management of rocky desertification area.The small-scale patch landscape pattern changes in rocky desertification areas also affect the ecological process of the region.Therefore,small scale study has important enlightenment to the future process of rocky desertification and the development of rocky desertification in the regional scale. |
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