The Study Onsensitivity Evaluation Of Rocky Desertification And Its Response To Human Intervention In Karst Areas

The karst area is one of the four fragile zones of the world's ecological environment.Under the influence of long-term uninterrupted human activities,the problem of rocky desertification is extremely prominent.The sensitivity of rocky desertification is to evaluate the degree of sensitivity of rocky desertification,which is the indicator and the prerequisite for the comprehensive management of rocky desertification and the restoration of ecological environment.At present,the research on the sensitivity of rocky desertification in China is relatively simple.The data volume is small,mostly one-stage data,the change law is not obvious,and the effect of human intervention on rocky desertification is less considered,which limits the guidance of the ecological environment management and protection of karst rocky desertification area under human intervention.This paper takes the demonstration area of Guanling-Zhenfeng Huajiang demonstration area as an example.According to the present situation of karst area natural environment and the characteristics of rocky desertification development,this paper used remote sensing and spatial analysis techniques,combined with remote sensing image data,geographic basic data and socioeconomic data,constructed the evaluation model of rocky desertification sensitivity and the evaluation model of human intervention intensity.The characteristics of the rocky desertification sensitivity evolution trajectory and its indication to the rocky desertification evolution were analyzed in detail.The sensitivity of the sensitivity to human intervention,and the risk of rocky desertification were evaluated,which can provide scientific basis for rocky desertification restoration and ecological management in karst rocky desertification area.It is the theoretical basis and prerequisite for comprehensive management of rocky desertification and ecological environment restoration and construction.The main research results of this paper are as the following:(1)According to the characteristics of rocky desertification sensitivity and the results of previous studies,five evaluation indexes such as carbonate rock,bedrock bareness,slope,vegetation coverage and land use were selected to understand the sensitivity of rocky desertification Evaluation.In 2016,the area of rocky desertification sensitive area was 3442.83 hm~2,accounting for 76.04% of the total area.Through the GIS spatial analysis method,the sensitivity of rocky desertification in the study area from 2000 to 2016 was improved to 16.14 percentage points.The evolution of the track to maintain the main type,the transfer area of 2437.78 hm~2,accounting for 47.34% of the total area.The change pattern of the insensitive region is dominated by the invariant type,the mild and moderate sensitivity is mainly composed of the complex variant,and the highly sensitive and the sensitive area are dominated by the holding type.(2)Based on the evaluation of human disturbance intensity,the intensity of human intervention in the demonstration area is moderate,accounting for 33.01% of the total area.In the spatiotemporal change of human disturbance,the area of microinvolution in 2000-2016 was steadily increased,and the area of mild intervention continued to decrease.Although moderate intervention and intensity intervention were complicated,the overall trend was reduced.There is a high correlation between the sensitivity evolution of rocky desertification and the intensity of human intervention,and it has a strong pertinence.The effect of mild,mild and moderate intervention is not sensitive to rocky desertification,mild sensitivity and moderate sensitive area,Intensity and extreme intensity intervention area are highly sensitive to rocky desertification and extremely sensitive areas.The paper also analyzes that different types of comprehensive management projects play a different role in the evolution of rocky desertification sensitivity,mainly for closing hillsides and fertilizers> fruit trees> slope change ladder> soil and water conservation forest> shelter forest> artificial grass.It can be seen that the sensitivity of rocky desertification can be effectively controlled as long as the corresponding measures are taken under different intervention intensities.(3)The risk of rocky desertification was evaluated to determine the risk of rocky desertification and the extremely dangerous areas.The area of rocky desertification and the area of extremely dangerous areas in the study area continued to decline in 2000-2016,the total reduction of 1152.39 hm~2,and the average annual reduction of 72.02 hm~2.However in 2016 the very dangerous areas rebounded.The distribution of the main area in the north of the North Panjiang erosion platform,was striped distribution.