| Liangzihu District,Ezhou City is located in the southeast of Hubei Province.It is one of the five city centers of Wuhan,Ezhou,Huangshi,Huanggang,and Xianning.Liangzi Lake in its territory is the freshwater lake with the largest storage capacity and the second largest area in Hubei Province.It is the "mother lake" of Wuchang fish.It is a key backup water source and ecological barrier for strategic development,and it is one of the suburban freshwater lakes with the most complete ecosystem and the best water quality in China.Because of its unique conditions,it has long been included in the list of famous wetlands in Asia and is a well-deserved world-class resource.However,in recent years,the social economy in Liangzihu District of Ezhou City has developed rapidly,the population has been increasing,and the contradiction between man and land has become increasingly prominent,which has caused a series of environmental problems.For example,the non-standard discharge of industrial sewage,waste gas,and waste residues,as well as agricultural production methods such as the extensive use of chemical fertilizers and pesticides,have brought great pressure to the ecological environment of the region.In addition,the massive development of tourism resources has also led to the destruction of the surrounding environment of Liangzi Lake,the reduction of vegetation coverage,and the exacerbation of soil erosion.At present,there are few studies on the spatio-temporal dynamic monitoring of ecological environment quality in areas with suburban freshwater lakes,resulting in very few relevant research results,and the ecological environment governance also faces many obstacles.In view of this,by efficiently and accurately controlling the evolution status and impact mechanism of the ecological environment quality in the region,it can provide greater protection for the stability and improvement of the ecosystem,thereby promoting the long-term and steady development of the social economy in the region,which is of great practical significance.This paper takes Liangzihu District of Ezhou City as the research object,focusing on the analysis of Landsat remote sensing images in three years: 2000,2010 and 2020.The main technical route is to create a Remote Sensing Ecological Index(RSEI)based on Principal Component Analysis(PCA),use data such as DEM,meteorology,and social economy to construct the temporal and spatial evolution of ecological environment quality from a visualization perspective,and explore the influencing factors related to its temporal and spatial changes.So as to evaluate the quality of ecological environment in Liangzihu District of Ezhou City.The main research conclusions of this paper are as follows:(1)The ecological environment indicators were constructed based on the indicators of greenness,humidity,dryness,and heat,and the evolution trend of each index factor affecting the quality of the ecological environment in Liangzihu District,Ezhou City from 2000 to 2020 was explored.The average value of the greenness index in 2000,2010,and 2020 was 0.61,0.38,and 0.35 in sequence,and its overall evolution showed a decreasing trend year by year;the average value of the humidity index in 2000,2010,and 2020 was 0.68,0.73,and 0.80 in sequence,its overall evolution presents a rising trend;the average value of the dryness index in 2000,2010,and 2020 is 0.58,0.51,and0.41 in turn,and its overall evolution presents a downward trend;the average value of the heat index in 2000 and 2010 In 2020,it will be 15.94,21.12,and 18.32,and the overall evolution will show a trend of rising first and then falling.(2)Based on the above ecological environment indicators,the overall evolution law of the ecological environment quality in Liangzihu District,Ezhou City from 2000 to2020 was explored.The mean values of RSEI in the study area in 2000,2010,and 2020 were 0.386,0.562,and 0.573 in turn,reflecting that the overall quality of the ecological environment is improving,and the quality grades are mainly good and excellent;in terms of spatial distribution,2000-2020 The areas of poor,poor,and medium grades in the study area are constantly decreasing,decreasing by 21.94 km2,134.42 km2,and 97.23km2,respectively,while the areas of good and excellent grades are expanding,increasing by 25.76 km2 and 193.70 km2,respectively.It shows that the overall quality of the ecological environment has a tendency to improve.(3)Based on the remote sensing ecological index,the temporal and spatial variation of ecological environment quality in Liangzihu District,Ezhou City from 2000 to 2020 was explored.From 2000 to 2010,the areas with good ecological environment quality in the study area were widely distributed,and the area of the category with the same ecological environment quality was 105.66 km~2,accounting for 19.64% of the total area,and the area of the category with good quality was about 2.66 times that of the category with poor quality;2010-2010 In 2020,the areas with poor ecological environment quality are mainly concentrated in the surrounding area of Liangzi Lake and the urban areas distributed along the river valley.From 2010 to 2020,the area of ecological environment quality in the study area is 182.24 km~2,accounting for 33.88% of the total area.The area of the category with better ecological environment quality is about 2.13 times that of the category with worse quality.(4)Based on human and natural factors,the factors affecting the quality of the ecological environment in Liangzihu District,Ezhou City from 2000 to 2020 were explored.From the perspective of factors affecting the ecological environment in the study area,among meteorological elements,annual precipitation and annual average relative humidity have the highest correlation with them,which are 0.847 and 0.638respectively;among topographic elements,if the elevation is within the range of18-111 m,the ecological The environmental quality is the best,and it will show a trend of improvement with the increase of the slope;among the socio-economic factors,the total population at the end of the year,the gross regional product,the primary industry GDP,the secondary industry GDP,the tertiary industry GDP,The added value of agriculture,forestry,animal husbandry and fishery,the total sown area of crops,and the total output of agricultural products all have a correlation with them of more than 0.7,and the total population at the end of the year has the highest correlation with them;in terms of land use types,when it is forest land,grassland,and water,the ecological environment quality preference,When it is cultivated land and construction land,the quality of ecological environment deviates;the quality of the ecological environment in the study area is significantly affected by policy promotion. |
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