Study On Boundary Optimization And Ecological Function Zoning Of Ecological Barrier Regions

Ecological barrier is an important factor to construct national ecological security strategic pattern in promoting ecological civilization construction.In the face of serious soil erosion,desertification and a series of problems affecting the national ecological environment,in order to improve the ecological environment as the goal,China has constructed different types of ecological barriers in different historical periods,and achieved obvious results.However,due to the lack of sufficient demonstration and planning and effective scientific guidance in the early stage of ecological barrier construction,there are still many problems such as blindness and uncertainty.On the one hand,the theoretical system of ecological barrier has not been formed,and the concept and connotation of ecological barrier need to be further explored.On the other hand,as the boundary of national ecological barrier area is fuzzy,the boundary and location of ecological barrier need to be further determined with the change of national ecological protection and restoration key areas.Therefore,it is of great significance to explore the theory of ecological barrier and to optimize and partition its boundary.Based on the view of ecosystem services,the concept and connotation of ecological barrier were put forward.Under the guidance of this theory,the boundary of national barrier area was identified and optimized according to the distribution characteristics of mountain range,forest,grassland and wetland ecosystem.Taking the Qinghai-Tibet Plateau ecological barrier region as an example,based on the key ecosystem services and ecological sensitivity of the region,an index system of ecological function zoning was constructed with the support of GIS technology.Sub-basins were taken as the minimum analysis unit,and self-organizing feature mapping network(SOFM)clustering method was used for zoning.Based on land use data from 2000 to 2018,the evolution characteristics of the ecosystem pattern in the barrier area were analyzed,and the comprehensive ecological quality index of vegetation was introduced to monitor the ecosystem in the barrier area from 2000 to 2018.The main conclusions are as follows:(1)This paper considers that ecological barriers are mostly located in the transition zone with certain geomorphic features(mainly refers to the topographic relief,such as the Qinghai-Tibet Plateau and Qinling Mountains;River and lake wetlands,such as the Yangtze River,the Yellow River and the Hinggan Mountains forest swamps,etc.)or vegetation cover has the ability of self-maintenance and self-regulation,can provide ecological functions for the sustainable development of human society,and has a clear object of protection and defense of the composite ecosystem.In space,it forms a multi-level,orderly and stable pattern of mountain-vegetation-wetland water area.In scale,it plays a role in ensuring the safety of the adjacent environment and even the ecological environment in a larger scale area.(2)The optimized and adjusted national barrier area reaches 4.19×106km~2,accounting for 44.08%of the land area,involving 25 provincial administrative regions and 792 county-level administrative regions.The main adjustment areas are as follows:extending the ecological barrier boundary of the Qinghai-Tibet Plateau to the southeastern part of the Plateau;The Loess Plateau-Sichuan-Yunnan ecological barrier is divided into the Loess Plateau ecological barrier and Sichuan-Yunnan ecological barrier.Establishing the ecological barrier between Qinling and Dabie Mountains;The Tianshan Mountains should be taken as an important part of the Tarim Sand Prevention Belt,and part of the desert area in the south of the Tarim Sand Prevention Belt should be removed.The barrier boundary should be adjusted according to the boundary trend of the Qilian Mountains,and the whole area of Qinghai Lake should be put under the Hexi Corridor sand control belt.The Yinshan Mountains and Helan Mountains should be included in the sand control belt of Inner Mongolia.The northeast forest belt extends to the south of Changbai Mountain;The southern hills and mountains extend to the Wuyi Mountains.(3)Based on the optimized adjustment of the qinghai-tibet plateau ecological barrier area as an example,the alpine grassland desertification sensitive area can be divided into west,middle meadow grassland agriculture and animal husbandry products supply area,northern tarim desert ecological fragile area,east of alpine grassland water production and biodiversity conservation,the eastern subtropical mountainous coniferous forest soil conservation area,southeastern tropical monsoon forest soil conservation area,southeastern tropical monsoon forest biodiversity protection and produces water seven ecological function areas.(4)Grassland was the main type of ecological barrier ecosystem in the Qinghai-Tibet Plateau from 2000to 2018.The area of forest and wetland ecosystem increased significantly in the ecological land,while the grassland ecosystem decreased by 136,474.42 km~2 due to the impact of climate change and human activities.In the non-ecological land,the urban area increased gradually,while the farmland and desert ecosystem increased first and then decreased.On the whole,the vegetation quality in the barrier area was at a low level.The mean values of the comprehensive vegetation ecological quality indexes in 2000,2005,2010,2015 and2018 were 23.98,24.64,24.98,24.36 and 25.76,respectively,indicating an overall upward trend,and the ecological quality of vegetation was continuously improving.