| Wetlands are the intersection and link of terrestrial and aquatic ecosystems,providing the best growing environment for plants and habitats for wildlife.As one of the important wetlands in north China,Dalinor wetland has the functions of microclimate regulation,water purification,flood storage and drainage.In recent years,the change of natural factors and the increase of human activities have led to the decrease of wetlands and the shrinkage of lakes,which indirectly caused the change of the surrounding environment and thus posed a threat to the ecological security of the whole region.Therefore,it is necessary to study the driving factors of wetland change in Dalinor Nature Reserve.In this paper,we preprocessed and interpreted five remote sensing images in 1986,1996,2006,2016 and 2019 in Dalinor Nature Reserve.Land use change rate,land use transfer matrix and quadrant orientation analysis were used to explore the spatiotemporal change characteristics of wetlands,and the driving factors of spatiotemporal change of wetlands were analyzed from the natural and socio-economic dimensions by using principal component analysis and grey correlation analysis The main conclusions are as follows:(1)From 1986 to 2019,the total wetland area showed a decreasing trend,from 333.75 km~2to 304.57 km~2,with a total decrease of 29.18 km~2.Among them,the area of lake wetland and river wetland decreased from245.57km~2and 11.87 km~2to 210.41 km~2and 3.95 km~2respectively,and the reduced area was 35.16 km~2and 7.92 km~2,respectively.The area of swamp wetland increased from 76.31 km~2to 90.21 km~2,with a total increase of 13.90 km~2.The total area of other land types increased from610.25 km~2to 639.98 km~2,with a total increase of 29.73 km~2.Among them,the area of grassland,residential land,transportation,special land and other land showed an increasing trend,while the area of woodland showed a decreasing trend.(2)In terms of wetland spatial change,Dalinor Lake shrank inward,the area of Dalinor Lake did not change significantly in the west direction;In the eastern direction,the area changed obviously,the reduced area was within 0.53～6.63 km~2.Most of the reduced area was transferred to marsh wetland,and a small part was transferred to other land(saline-alkali land).Ganggang Lake expanded slightly outwards,the area of the lake did not change significantly in the west direction;In the eastern direction,the increase area was within 0.10～0.76 km~2,and the increase area was transferred from marsh wetland.The river wetland was distributed linearly,and its width and length decrease to a certain extent.Many rivers were cut off in the middle of the river,and the small closed rivers around them became less and less,and were transferred to marsh wetland,grassland and other land.Marsh wetlands were in a trend of expansion,Dalinor Lake and Gonger River marsh were both expanding,and Ganggang Lake marsh were shrinking slightly.(3)In this paper,the driving factors of Dalinor wetland were analyzed from the natural and social economic aspects by using principal component analysis and grey correlation analysis.The results showed that the area changes of lake wetland,river wetland and marsh wetland had a high correlation with evaporation,air temperature,population and livestock,and the values were all higher than 0.640;and the total output value of agriculture,animal husbandry,forestry and fishery were all lower than 0.500.The results showed that evaporation,air temperature,population and livestock were the main driving factors affecting the wetland area change,while tourism,total output value of agriculture,animal husbandry,forestry and fishery had a weak influence on the wetland area change. |
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