Monitoring And Evaluation Of The Ecological Environment In Chuan-dian Ecological Barrier Region

The ecological environment is composed of many elements such as water,soil,rocks,forests,and the atmosphere.Among them,water,soil,and vegetation are closely related to human life.It is a prerequisite for human survival and development,and changes in the ecological environment are constantly changing.This change influences life every moment.Facing the ever-increasing economic growth and protection of the ecological environment,the ecological environment is facing severe challenges.The national ecological security strategy of“Two Screens and Three Belts”divided by the main functional areas is attracting more and more attention.,This article takes the Chuan-Dian ecological barrier region(hereinafter referred to as“barrier region”)as the research object,Which has a filter barrier region,buffer,shelter,and water and soil conservation effect,people can shelter some areas,sand-fixing,provide an ecological security barrier for human survival and development.Therefore,in order to maintain the ecological security of the barrier area,it is necessary to monitor the vegetation coverage and soil erosion of the ecological environment and evaluate it.It is of great significance to maintaining the virtuous circle of the barrier area and promoting the stable development of the region.Based on the ArcGIS and ENVI software,this paper estimates the fractional vegetation coverage and soil erosion of the barrier area in2010 and 2015 respectively,analyzes the changes over the past five years,and makes a comprehensive evaluation of the ecological environment status of the barrier area in 2015.The final expression is in the form of a map,which facilitates intuitive analysis.Comprehensive evaluation results can be used by relevant departments to formulate corresponding decision-making sources.The main research contents and results are as follows:1.Estimation of fractional vegetation coverage(FVC):using the Landsat series of satellite image data,the fractional vegetation coverage was estimated using the normalized difference vegetation index(NDVI)and the pixel binary model.This method can reflect the growth of vegetation well.The results of the study showed that the overall fractional vegetation coverage in the barrier area was better,with a slight decrease compared to the two periods;according to statistics,the high vegetation coverage in 2010 mainly covered an area of 167,827 km~2 and the high coverage rate reached 86%;however,The high vegetation coverage in 2015 has declined,with a decline area of 45,723 km~2.The coverage of the barrier area is mainly medium and high coverage,with coverage rates of 31%and 62%,respectively;regional low coverage,poor coverage,and water bodies are all less than 5%.Due to unreasonable development and utilization of people,the fractional vegetation coverage of the region has shown a downward trend.2.Water and soil loss monitoring:based on the ground cover data and related thematic data as the basic data,the paper uses the Chinese soil loss equation(CSLE)model to quantitatively analyze the soil erosion under the conditions of water erosion.First,the soil erosion factors,rainfall factors,terrain factors and soil and water conservation measures required by the model were extracted.Secondly,the soil erosion modulus and erosion area were calculated.Finally,the soil erosion intensity was classified according to the classification criteria for soil erosion classification.The results show that the water and soil erosion in the barrier area is mainly in a mild and microscopic state.In 2010,the average soil erosion modulus reached 645.72 t/(km~2·a),the area reached 34305.07 km~2,and the total annual soil erosion amounted to 126 million tons.The micro and mild intensity levels in the region accounted for 82.37%and 13.72%of the total area respectively;in 2015,the average erosion modulus was 481.22 t/(km~2·a),the soil erosion area was 37,800 km~2,and the proportion of soil erosion reached rate of 19.41%,mild erosion and moderate erosion together accounted for 93.21%of the total area of soil erosion.The area of soil erosion still expanded 3,463.07 km~2 in 5 years,with an increase rate of 1.78%.However,the erosion modulus and the intense,extremely intense,and severely eroded areas all show a decreasing trend.3.Comprehensive analysis of the ecological index(EI):based on the surface cover data,select the vegetation cover index,water network density index,land stress index,and habitat quality index to construct an eco-environment evaluation index system,and determine the right and calculate the normalized index and then evaluate the eco-environmental status of the ecological barrier region in Chuan-Dian in 2015.The evaluation results showed that the overall eco-environmental status of the barrier area was relatively good in 2015.The index was mainly changed from 56 to 93,and the average value was 69.99.All of them belonged to excellent grades,among which 9 counties were evaluated as excellent,the remaining 22counties all belong to good.In terms of spatial distribution,the eco-environment in the southwest region is superior to that in the northwest region,showing an increasing trend from northwest to southeast,and the eco-environmental status of Yunnan Province is superior to that of Sichuan Province.In general,the ecological barrier zone in Chuan-Dian is rich in biological diversity,high in vegetation coverage,and maintains a virtuous circle of ecological environment,which is more suitable for human life.