Research On Spatio-temporal Evolution And Optimization Of Territorial Space In Lushui Based On "Three Types Of Space"

As a typical alpine valley area,Lushui has very limited land resources.Under the current situation of shortage of reserve cultivated land resources,some cultivated land is facing the situation of returning to farmland due to unreasonable distribution.Urban expansion is limited by natural conditions.At the same time,Nujiang Prefecture is striving to build the Nujiang River into a pioneering demonstration base for ecological civilization construction and a core demonstration area for international biodiversity conservation.The present situation of land use shows that the contradiction between ecological space,agricultural space and urban space in Lushui is increasingly intensified,and the optimal utilization of territorial space is particularly important.In this context,this study takes Lushui as the research area to study the spatio-temporal evolution characteristics of "three types of space" and optimization methods of its territorial space.Firstly,the spatial and temporal evolution characteristics of "three types of space" in Lushui city are analyzed from the perspective of time change,spatial pattern change and landscape pattern change by selecting the territorial spatial data of 2000,2010 and2020.Secondly,based on the importance of ecological protection,the suitability of agricultural production and urban construction,an evaluation index system is established to evaluate the suitability of territorial space development in Lushui.Thirdly,based on the spatio-temporal evolution characteristics of "three types of space" and the suitability evaluation of territorial space development,the problems existing in the current territorial space of Lushui city are analyzed.Finally,aiming at the existing problems,optimize the territory space of Lushui city and put forward the optimization plan..The main conclusions of this study are as follows:(1)From 2000 to 2020,the urban space and ecological space of Lushui shows a trend of expansion,while the agricultural space shows a trend of decline.Among the three spatial types,the single dynamic attitude of urban space has always been the largest.The comprehensive dynamic attitude of territorial space has an increasing trend from 2000-2010 to 2010-2020.The transfer of "three types of space" is mainly between agricultural space and ecological space.The agricultural space and urban space of Lushui are mainly distributed along the two banks of Nujiang River,while the ecological space is mainly distributed in the high altitude area in the east and west of Lushui.In terms of each township,the change trend of the three types of space is slightly different from that of the three types of space in Lushui City.With the increase of altitude,urban space area decreases.Agricultural space decreases with the increase of altitude and increase with the increase of slope.From 2000 to 2020,at the landscape level,the dispersion degree of land space in Lushui decreases and the aggregation degree increases.(2)Based on the evaluation results of territorial space development suitability,Lushui is dominated by ecological space,and the height suitable and relatively suitable areas for agricultural production and urban construction are relatively small.Especially for urban construction,highly suitable and relatively suitable areas account for less than 2% of the total area of the study area,and urban development is seriously affected.The suitable areas of agricultural space are mainly distributed on the banks of the Nujiang River and its tributaries.(3)The main problems of land space utilization in Lushui city are as follows:Deforestation for land reclamation still exists;Urban spatial slope is relatively large,and urban expansion occupies a lot of arable land;The awareness of ecological protection is weak,and the development and utilization of territorial space is distributed in highly and relatively important areas for ecological protection;The spatial distribution of agriculture is unreasonable and the way of utilization needs to be improved.In view of the specific problems,five types of territorial space optimization regions are divided: potential abandoned farmland area,urgent adjustment of agricultural production mode,key prevention area of urban space ecological problems,key prevention area of agricultural space ecological problems,and potential expansion area of urban space.Among the five optimization regions,the adjustment of agricultural production mode is the main one,accounting for about 75% of the optimized area,which can not only ensure food security but also reduce the damage to the ecological environment,mainly distributed in Liuku Town,Shangjiang town,Chenggang township and Gudeng township;The key prevention area of agricultural space ecological problems is the second,which mainly targets at the agricultural space of the more important ecological protection areas,mainly distributed in Shangjiang Town,Pingma Town and Luzhang Town;The project of returning farmland to forest is also one of the important ways of territorial space optimization,which mainly targets at areas with high importance of ecological protection and areas with poor or less suitable agricultural production,mainly in Chenggang and Gudeng Townships;The potential expansion area of urban space is mainly in Liuku Town,while the key prevention area of urban space ecological problems is only a little distributed in Pingma Town.