Study on the characteristics of land use change in Chishui River Basin from 1990 to 2018
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Graphical Abstract
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Abstract
Changes of land use can directly reflect the extent of human activities. The Chishui River is an important tributary of the upper reaches of Yangtze River Basin. In the context of the great protection of the Yangtze River, mastering the dynamic changes of land use is conducive to land optimization management and regional sustainable development. Based on the land use data of seven periods from 1990 to 2018, and according to the regional characteristics, seven land use types, i.e. paddy field, dry land, forest land, grassland, water area, urban and rural construction land, and unused land were integrated to analyze the spatial distribution and temporal and spatial changes of land use types in Chishui River Basin in terms of distribution pattern, single dynamic degree of land use, and land use transfer matrix. The results showed that the area proportions of land use types in Chishui River Basin was in the order of forest land> dry land> paddy field> grassland> urban and rural construction land> water area> unused land. The forest land was widely distributed, mainly concentrated in the lower reaches of Chishui River Basin. Dry lands were mostly distributed in the upper reaches of the basin, and paddy fields were mostly distributed in the lower reaches of the basin. Grassland and urban and rural construction land were mostly distributed along the river valley. The dynamic degree of each land use type gradually increased over time. The dynamic changes of grassland, urban and rural construction land increased significantly from 2015 to 2018. Affected by the policy of returning farmland to forest, there has been more conversion between forest land and dry land, and the degree of conversion in 2006-2015 was higher than that in 1990-2000. The conversion of grassland, urban and rural construction land and other land use types increased significantly in 2006-2015 and 2015-2018. The total GDP growth rate of Chishui River Basin had been increasing year by year and, compared with the growth rate of urban and rural construction land, it had slowed down from 2015 to 2018. The economic output per unit of construction land area had been decreasing year by year, so the land use efficiency needed to be improved.
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