Spatio-temporal Change And Optimization Allocation Of Land Use Pattern In Qinling-Daba Mountains

In recent years,the rapid population growth,the rapid development of industrialization and urbanization,and the unreasonable land use patterns of human beings have led to extensive and inefficient construction land,urban spatial distribution and irrational scale structure and a series of land ecological problems,which seriously affects the healthy life,urbanization and sustainable socio-economic development of human beings,threatens national food security and ecological security,and increases the cost of social economy and ecological environment.Qinling-Daba Mountains,located in the intersection of north and south climate and biota in China,is an important geographical and ecological boundary line,the only large-scale ecological corridor connecting the east and the west,an important national biodiversity and water conservation ecological function area,a concentration of special hardship areas and national key poverty alleviation development zones.At the same time,the area is a prone to frequent occurrence of geological disasters in China,its ecological fragility,serious soil erosion,and frequent natural disasters such as landslides,mudslides,floods and droughts.With the rapid population growth and high-speed urbanization development,mankind has increased the use of land resources,and the contradiction between regional land resources and development construction and ecological environmental protection further increase,which has caused great ecological damage to the originally vulnerable Qinling-Daba Mountains area and seriously affected and hindered the sustainable development of regional land resources and economic construction.The scientific and rational land use optimization configuration is of great significance for adjusting the land use space structure,promoting the intensive production space,the moderate living space,and the ecological space.Although there are some researches and methods for the optimal allocation of land use,the research on the optimal allocation of land use based on ecological security is still lacking.Therefore,this paper takes Tongjiang County as the research prototype,which is national restricted development zone and an important ecological function area in Qinling-Daba Mountains.Based on remote sensing data,topography,meteorological data,geological hydrology,soil data and text statistics,the spatial-temporal changes of land use landscape pattern and the analysis of topographic gradient effects in Tongjiang County,land use landscape simulation,constructing landscape ecological security pattern and functional division,realizing optimal allocation of land use landscape based on ecological security pattern are carried out.Quantitative analysis of the spatial distribution of land use landscape optimization provides technical support and ideas for the optimization of land use planning and land use spatial pattern in Tongjiang County and Qinba Mountain Area.The main research results obtained in this thesis are as follows:(1)According to the optimization allocation of land use pattern based on ecological security pattern in Tongjiang County of Qinling-Daba Mountains,it can qualitatively and quantitatively analyze and simulate land use landscape,and link the ecological process of land use landscape change with the ecological security pattern of the study area.The land use landscape optimization area has been implemented,which plays an important role in alleviating the extensive and inefficient land use methods,land ecological safety hazards and the contradiction between development and construction and ecological environment protection,and proposes a new idea for optimizing the land use landscape pattern,which provides technical support and ideas for reference for regional land use planning and spatial adjustment of land use types.(2)Based on the random forest method,the land use data of 2015 remote sensing images was extracted.According to the 2015 land use data,the land use data of the study area in 2010 was obtained by visually interpreting the remote sensing images of 2010 and 2015,and the land use data of the study area in 2000 and 1990 were obtained in turn.From 1990 to 2015,the area of forest land,construction land,waters and other land uses continued to increase,the area of cultivated land continued to decrease,and grassland dynamics changed.Land use landscape transformation mainly occurs between cultivated land and forest land,construction land and other land use,between forest land and other land and grassland,between water and other land.The rolled-out method is cultivated land and forest land,and the rolled-in is forest land and construction land.(3)Cultivated land have the highest degree of fragmentation and the most complicated shape.The forest land is the dominant landscape and has absolute advantages and the highest degree of polymerization.From 1990 to 2015,the degree of fragmentation of both cultivated land and forest land decreased,the external disturbance decreased,the dominance decreased,the degree of forest land polymerization increased,and the degree of fragmentation,dominance and polymerization of water,construction land and other land increased.The degree of reunion,complexity,fragmentation and connectivity of the Tongjiang landscape increased from 1990 to 2015,and the dominantness of the landscape declined.From 1990 to 2015,region below 900 m is an increased area of landscape fragmentation degree and rich variety of landscape,region above 900 m is a reduced area of landscape fragmentation degree and an absolute dominant landscape.The land use landscape is affected by the topography and has obvious terrain gradient effect.In the optimization of land use landscape,the land use is adjusted according to its regular characteristics.(4)Taking the land use landscape in 2000 as a data source,the land use landscape in 2015 was simulated based on the CLUE-S model,and the simulation effect was good.Based on the CLUE-S model to simulate the land use landscape in 2030,the landscape pattern of land use has remained basically unchanged,and the area of forest land,construction land,water area,grassland and other land use has increased,and the cultivated land has been reduced.(5)Based on the MCR model,the minimum cumulative resistance surface of the expansion source and the ecological source is constructed according to the urban expansion and the ecological land expansion.The ecological safety pattern function is divided into the study area by the minimum cumulative resistance difference between the two landscape processes.It is divided into ecological protection area,ecological buffer area,ecological sensitive area and production and living area,which provides a reference for land use planning and distribution rationalization.According to the functional division of ecological security pattern,the production and living areas are mainly distributed in plain are with an area of 433.09km2;the ecological sensitive areas are mainly distributed in hilly areas with an area of 1076.07km2;the ecological buffer areas are mainly distributed in hilly areas and low mountainous areas with an area of 1708.81km2;ecological protection areas are mainly distributed in the middle mountain area and low mountainous area with an area of 906.79 km2.(6)Based on the ecological security pattern and carrying out the optimal allocation of land use landscape in Tongjiang County,the area of forest land and water area in increased,the cultivated land,grassland and other land use decreased,the construction land increased slowly,the degree of landscape fragmentation decreased,and the degree of aggregation increased.The connectivity between the various landscape patches increases,the complexity of the landscape decreases,the disturbance of human activities is reduced,and the land use landscape structure is more in line with the requirements of regional ecological and development considerations.The land use benefits are improved,and both development and utilization are ecological.From the perspective of the spatial distribution of the optimization area,the typical ecological optimization area is in the north,the typical ecological and development optimization area(transition optimization area)is in the central part,and the typical production and life optimization area is in the south.