| In the context of social and economic development and accelerated urbanization,the demand for construction land keeps rising,which leads to continuous human interference and occupation of the area of ecological land in land use,and increasingly obvious and serious problems such as the imbalance of land use space and the continuous deterioration of ecological environment.Dongchuan District is a typical resource-exhausted city.Due to human factors such as climate change,rapid urbanization and extensive exploitation of mineral resources,the ecological environment of Dongchuan District is extremely fragile,soil and water loss is serious,geological disasters are frequent,economic development and natural protection are unbalanced,and biodiversity is seriously damaged.The degradation of ecological function in Dongchuan District has seriously affected the region and economy in the middle and lower reaches of the Yangtze River.In this context,the construction of ecological network in Dongchuan district not only contributes to regional ecological restoration but also serves as a reference condition for land use zoning planning.Therefore,the suitability zoning based on ecological network helps to improve the ecological effect of land use in Dongchuan district from the overall direction of "point-line-plane".In response to the proposition of promoting ecological priority,economizing and intensive,green and low-carbon development of the The 20 th National Congress of the Communist Party of China,this paper takes Dongchuan District of Kunming City as the research area,analyzes the land use cover change and MSPA landscape type change in 2000,2010 and 2020,and puts forward the existing problems in the land use of Dongchuan District.Based on the MSPA landscape type distribution in Dongchuan District in 2020,the important ecological source was extracted by landscape index method,the ecological corridor of Dongchuan district was constructed by MCR model,the importance level of corridor was quantitatively analyzed by gravity model,and the important corridor was screened by combining with the actual situation of Dongchuan district.According to the distribution of important corridors and related resistance factors,the minimum cumulative resistance difference method was used to identify the suitable zoning of land use in Dongchuan District.The results show that:(1)The main area of Dongchuan District is grassland,accounting for 52.04% of the study area,28.76% of the total area of forest land,and 12.98% of the total area of cultivated land,forest land and grassland interwoven in the region;Unused land accounted for 2.93% of the total area,water area 2.17%,and construction land 1.11%.According to the land use change and landscape type distribution changes in 2000,2010 and 2020,the changes among woodland,cultivated land and grassland in Dongchuan district were the largest,and the woodland showed an overall growth trend.However,according to the landscape type distribution changes,the fragmented woodland patches in Dongchuan district were reduced,the quality of the core area was improved,but the overall connectivity needed to be strengthened.(2)Through Confer software,ten plaques with d PC > 5 and d IIC > 2 were identified as the major ecological source.Among the ten plaques,the d PC value of plaque 1 was the highest,reaching 31.01795 with an area of 3991.95 h m2,and the d PC value of plaque 4 was 26.74395.The area of patch 1 and patch 4 is 5832.09hm2.Patch 1 and patch 4 are adjacent to the Jiaozishan National Forest Ecological Nature Reserve in Dongchuan district,and even cover part of the nature reserve area.Besides,patch 1 and patch 4 are the first-level forest protection area in Dongchuan District.(3)45 potential ecological corridors in Dongchuan were generated based on the MCR model,and 18 important corridors were identified according to the matrix of interaction intensity between ecological sources identified by the gravity model,and the remaining 27 were general corridors.Network closure α,line point rate β and network connectivity γ index were used.For the whole ecological network,the network closure α,line point rate β and network connectivity γ index were obtained by the formula,which were 0.43,1.7 and 0.63,respectively.For the extraction of important corridors,the network closure α was calculated by the formula.Line point rate β=2;The network connectivity is γ=0.86,and the material circulation and fluency of important corridors are significantly improved compared with the overall corridor.(4)Based on the constructed ecological network,Dongchuan was divided into five land use zones by using the difference of the minimum cumulative resistance surface between ecological expansion and urban expansion,including three ecological security zones at high,medium and low levels,and two construction zones were divided into buffer zone and agglomeration zone.The ecological security zone accounted for 73.53% of the total area of Dongchuan District.The area of high-level ecological security zone in Dongchuan District is 11805.3hm2,accounting for 8.71% of the whole ecological security zone area and6.4% of the total land area of Dongchuan District;the area of medium-level ecological security zone is 30788.55hm2,accounting for 22.71% of the whole ecological security zone area and 16.7% of the total land area of Dongchuan District.The area of low level ecological safety zone was 92,975.67 hm2,accounting for 68.58% of the whole ecological safety zone area and 50.43% of the total land area of Dongchuan District.(5)According to the constructed ecological network and ecological suitability zoning,two suggestions on ecological security land use were put forward.It includes protecting ecological sources,strengthening the protection of corridors and stepping stones,and planning ecological safety zones at different levels.According to the location area and ecological protection concept,measures and suggestions for ecological security of land use in different zones are proposed,including coordinated management of various government departments,construction of towns with local characteristics,regional land use planning according to local conditions,building ecological target land use model,strengthening the construction of ecological barrier,and promoting ecological restoration. |
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