| The Bashang Plateau is located in the northwestern part of Hebei Province and the southern edge of the Inner Mongolia Plateau.It refers to the area formed by the sudden rise of grasslands and the meadow-like grasslands formed due to climate and vegetation.This area is an important ecological barrier in the north of China to prevent the invasion of wind and sand,and its geographical location and ecological function are extremely important.Beginning in 2000,the area of wetlands in the region has shrunk significantly,and many lakes and lakes scattered in the original have shrunk and dried up.Due to its special geographical location 200km from the capital Beijing,the changes in the ecological geological environment caused by the shrinking of wetlands cannot be underestimated.This study is based on long-term serial remote sensing image data,and uses human-machine interactive interpretation methods to extract wetland information and its change data through a GIS platform,extracted the wetland resource data of Bashang Plateau Wetland in 2000(ETM+),2010(TM),and 2018(Landsat 8 OLI)respectively,analysis of the spatiotemporal distribution characteristics and changes of wetland resources in Bashang grassland from 2000 to 2018 through comprehensive comparison;at the same time,the long-term serial remote sensing images of the Anguli lake,the largest plateau inland lake in the northwestern inland region in the past 40 years from 1975 to 2018,were used to quickly and effectively extract the water surface area of Anguli lake,and comprehensively analyze its area changes.On this basis,combined with the climatic and hydrogeological conditions of the study area,the reasons for the change of the wetland resources in the study area are analyzed in depth,and the current situation of wetland protection in the study area is provided to provide suggestions for the ecological restoration of the wetland in the study area.The main results are as follows:1)Based on the Ramsar wetland classification system and the natural environment characteristics of the study area,a remote sensing classification system for the Bashang Plateau wetland was established.2)Human-machine interactive interpretation through the Arcgis software platform,extraction of wetland information in the study area,comprehensive analysis of long-term sequence image characteristics of the study area,combined with the established remote sensing classification system for the Bashang Plateau wetland to form the interpretation mark of the study area,including River wetlands,lake wetlands,marsh wetlands and constructed wetlands.Before detailed interpretation,verify the accuracy of the interpretation marks through the field and correct the incorrect parts to make the extracted information more accurate.3)From 2000 to 2018,the area of wetland resources in the study area decreased from796.90 km~2 in 2000 to 666.24 km~2 in 2018,and the number of wetland resource patches decreased from 731 in 2000 to 316 in 2018.In 18 years,the area of wetland resources decreased by 130.66 km~2,the number of patches decreased by 415,and the reduction rate was 7.26 km~2/year.From the perspective of wetland types and spatial changes,the lake wetland area has decreased significantly,and the shrinking trend in the western part of Bashang area is higher than that in the eastern part.The area of reduced lake wetland area is mainly the northwestern inflow area of the Bashang Plateau.From 2000 to 2018,the lake area was 146.93 km~2 and the patch data decreased by 366.4)Through a comprehensive analysis of meteorological data from multiple meteorological stations in the study area from 1975 to 2018,the precipitation in the study area gradually decreased,the annual average temperature gradually increased,and the rising trend was obvious.At the same time,the interception of a reservoir built upstream of the study area prevented surface water from flowing to the wetland area,resulting in reduced wetland water recharge;the groundwater resources drawn from agricultural production in the zone continue to increase,causing the groundwater level in the zone to continue to decline.The artesian wells are almost completely cut off,and the lake water springs are gradually drying up,resulting in the continuous reduction of the area of wetlands.So,the change in the wetland area of the Bashang Plateau is mainly driven by climate,hydrogeological conditions,and human activities.5)Based on this,this study proposes the need to increase vegetation restoration and carry out water conservation projects;Promote water-saving irrigation technology in accordance with local conditions in the river basin,and promote advanced experience of increasing production and income by water-saving irrigation;returning farmland to wetland,returning construction land to wetland,reducing the use of off-season vegetable cultivation with large water consumption,and removing unnecessary river closure projects upstream;Vigorously promote suggestions for the control of saline-alkali desertification in lakes and lakes. |
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