| With the development of cities,the sustainability of land use is becoming more and more important.The ecological environment of a region can reflect whether the land use and regional development are in a state of sustainable development.Therefore,the research on the direction of the ecological environment is one of the directions to analyze the sustainable development of land use.Urban agglomeration in the central Yunnan economic development better,most of the area in a plateau mountain range,rich resources,and relatively flat topography,the dam,but it is in recent years,the rapid development of the city for urban agglomerations faces a limited amount of resources and environment foundation,insufficient per capita,uneven distribution of resources,backward economic development,and fragile ecological environment and so on all kinds of pressure.This study based on remote sensing image data and puts forward all kinds of land use,combined with social and economic data from 1990 to 2018 in Yunnan urban agglomeration districts and counties of land-use change,land-use change and driving force,the landscape pattern change,land-use change(LUCC)and its ecological contribution,ecological quality evaluation(ESV)are studied,such as the future development of land for urban sustainable development,urban agglomeration planning have certain reference value.The conclusions are as follows:(1)The proportion of forest land in the central Yunnan urban agglomeration has been in absolute advantage for 28 years,with 49.1%,followed by grassland and arable land;among all types of land,the area of construction land has increased the most;the study area has changed,and the area of arable land,grassland and woodland has decreased.In most districts and counties,the area of forest land is relatively high,construction land and water are relatively small,followed by cultivated land and grassland.In terms of time changes,the construction land of various districts and counties has increased more,and the cultivated land and waters of some districts and counties have increased,and some Decrease;The water area of some districts and counties has increased,and water area and grassland of some districts and counties decreased.The grassland and woodland decreased.The total water area of urban agglomerations has increased.(2)The change rate of forest land decreased,the change rate of construction land and water area increased,and the change rate of cultivated land increased from decrease to increase in central Yunnan urban agglomeration.The land use degree of urban agglomeration is increasing continuously;The change of land uses/used transfer of urban agglomeration was as follows: the area of grassland transfer was the largest,and the area reduction was the largest;The transfer area of construction land is the largest and the area increment is the largest.Transfer and distribution of urban agglomeration land: after a transfer,more construction land was distributed in the central cities of several prefectures,and forest land was distributed in the east and southwest of the study area.Grasslands are distributed among the eastern and central areas of the study area.Urban agglomeration land expansion: From 2000 to 2010,urban agglomeration experienced a high-intensity and high-rate expansion mode;The development and expansion degree of each district and county is different,and the expansion of the previous period will have a certain influence on the development of the future.The compactness of some districts and counties increased and then decreased.From 1990 to 2018,the urban agglomeration expanded on/upon NW as a whole.(3)Landscape pattern of urban agglomeration: the landscape diversity of urban agglomeration increased,the fragmentation of other lands except for construction land gradually increased,the shape became complex,and the interference of human activities to the landscape of all kinds of land increased.With the development of the city,except for the increase of landscape type connectivity of construction land,the rest of the land decreased and the degree of fragmentation increased;in terms of dominant types,woodland was an obvious dominant type;in terms of connectivity,the connectivity of construction land decreased after increasing.In terms of the driving force of land use,from 1990 to 2000,the area of cultivated land had the greatest impact on the expansion of urban agglomeration.with the development of the city,the impact of cultivated land area on the city gradually decreased.According to the analysis of 24 driving factors by SPSS,the total population and urban population had a cumulative value of 84.92%.(4)Changes in the value of EV and ESV of urban agglomerations: The ecological quality index of each region in the urban agglomeration has gradually decreased.About 59% of the districts and counties have a decline in the quality of the ecological environment,32%of the areas where the ecological environment has increased,and 9% of the areas have no change.The higher the slope within the central Yunnan urban agglomeration,the better the quality of the ecological environment.Forest land is directly or indirectly converted to construction land.A large area of cultivated land around the built-up area of the central city is converted to construction land.A small part of the waters of Dianchi Lake near Xishan District is converted to construction land,which directly causes the reduction of EV value;various types of land are indirectly in each area.The conversion to construction land and the conversion of land with high EV value like forest land to medium EV value,such as cultivated land,also caused the deterioration of the regional ecological environment.The ESV value of food production is the lowest,and the ESV value of biodiversity protection is the highest;the ESV of woodland is the highest,and the ESV of construction land is the lowest.The average land-average ecosystem service value of the central Yunnan urban agglomeration is generally reduced;from the spatial distribution,it can be seen that the low land average ESV is mainly distributed in the eastern part of the urban agglomeration,including areas such as Luliang,Luoping,and Qilin;the areas with high land average ESV are mainly distributed in Eshan,Dayao,Yuanjiang,and other regions.When the slope is less than 3 degrees,the treatment value of hydrological regulation waste is larger,when the slope is more than 3 degrees,the values of biodiversity conservation and soil formation and protection are higher,while the values of food production and aesthetic landscape are lower.Using the grid to calculate the ecosystem service value,we can know that the distribution within the urban agglomeration is low in the east and high in the west,and there are great differences between districts and counties.In agglomeration,the regional agglomeration type of woodland and water area is a high-high cluster.The regional agglomeration type of construction land is a low-low cluster.Suggestions: change the key direction of urban construction,change the direction of urban construction land.The growth source of construction land in central Yunnan urban agglomeration should be more strictly controlled;for the main urban area of Kunming,through the development of surrounding satellite cities,the cultivation of medium-sized cities,or the refinement,upgrading,and utilization of existing land.We will increase the protection of cultivated land,lakes and woodlands,and reduce the conversion of highquality cultivated land resources into construction land.Promote the optimization and upgrading of industrial structure,improve the level of land development,and guide the integration of production and city for the future industrial development of various regions.Increase the intensity of environmental protection in central Yunnan and its surrounding areas.According to different levels of cities,pay attention to optimize the compensation mechanism of the ecological environment.Build a systematic landscape pattern on the scale of urban agglomeration to promote the sustainable development of the region. |
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