| Bashang plateau in Hebei province belongs to a typical climate transition zone and an agro-pastoral ecotone,and its ecological environment is extremely fragile.Lake is the main geographical unit,served as an important water source for the region.It plays an important role in regional ecological stability,promotes the development of regional industrial and agricultural and tourism economy.In the past30 years,due to the combined effects of climate change and human activities,regional lakes have shown a trend from expansion to shrinking,which directly affects the ecological security of the plateau and surrounding areas.Therefore,it is an important task to research and analyze the law of lake changes in Bashang plateau,will play an important role in regional reasonably water resources protection and ecological balance maintaining.Selecting the Landsat images from 1984 to 2015,this research uses the method of visual interpretation,ERDAS and ArcGIS technology to extract the lake areas of the Bashang plateau(>0.1 km~2),obtained the temporal and spatial evolution law of the research area,Combining meteorological data and human activity data,this study qualitatively analyzes the role of climate change and human activities in the lake evolution.Then using relativity analysis,quantitatively analyzes the main driving forces affecting the change of lakes in the Bashang plateau.The main findings of this research are as follows:(1)The number of lakes with an area over 0.1 km~2 is 69,155 and 28 in 1984,1996 and 2015,and Corresponding to respectively area of the lake area is 84.38 km~2,199.41 km~2 and 25.22 km~2.The change of lake number is consistent with the change of lake area,and the overall trend is upward and then downward.And the mainly area of the lakes in Bashang plateau is from 0.1 km~2 to 1 km~2.(2)From a spatial point of view,the distribution of lakes on the Bashang plateau is obviously regional,which is concentrated in the central and western regions,especially in the western regions.(3)From 1984 to 2015,the lakes on the Bashang Plateau shows a shrinking trend,but the evolution trend of lakes in different periods is obviously different in different stages.And the change trend of lakes is also different in different regions.In terms of time,1996 is an inflection point in time.The lake area and the number of lakes on the Bashang Plateau increases significantly from 1984 to 1996,with an additional Lake area of 115.03 km~2 and the number of lakes increased by 86.From 1996 to 2015,the area of lakes and the number of lakes on the Bashang Plateau decreases significantly.The area of lakes decreases by 174.19 km~2,and the number of lakes decreases by 127.In space,the evolution trend of lakes in the central and western regions is consistent with the overall evolution trend,while the evolution trend of lakes in the eastern region is not consistent with the overall evolution trend.(4)The results of driving force analysis show that there are obvious differences in driving factors of lake changes between 1984-1996 and 1996-2015.During1984-1996,the area change of regional lakes is mainly influenced by climatic factors,but less affected by human activities.During 1996-2015,the area change of regional lakes is affected by human activities,and the impact of human activities is significant.Among them,the large-scale planting of water-consuming crops such as vegetables may be the main human activity mode that causes the lake to shrink. |
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