Remote Sensing Study On Typical Lake Wetland Changes Under Hydrology And Reclamation

Wetlands are one of the most productive ecosystems in the Earth's surface layer and play an important role in maintaining a balance between the Earth's ecosystems.Wetlands not only have important functions such as regulating runoff,flood storage and drought prevention,and degrading pollution in ecological aspects,but also play an important role in providing breeding and wintering sites for many rare wild animals,as well as providing various resources for human production and living.However,under the background of natural environment changes and human activities,the vulnerability and sensitivity of wetland ecosystems are exposed.The wetlands gradually have problems such as shrinking area and degrading ecological functions.The protection and rational use of wetland resources has become a hot issue in global research.In recent years,domestic and foreign scholars' research on wetlands has focused on wetland ecosystem evaluation and wetland resource survey,and has improved the accuracy of wetland information acquisition and revealed wetlands.The drivers of dynamic change are particularly important.This paper uses Landsat remote sensing images as data sources,Hulun Lake(1984,1996,2006 and 2015),Alahu Group(1989,1996,2006 and 2015)and Dongting Lake(1986,In 1995,2005 and 2015,according to the established wetland classification system,the wetland information was extracted from the three research areas by using the support vector machine classification method,and the confusion matrix was used to verify the accuracy of the classification results.The change of wetland in the study area in time and space,and the driving factors affecting the wetland change in the study area from the natural and human factors.(1)Between 1984 and 2015,the total area ofHulun Lake wetland decreased continuously,and the area decreased by 121.7 km2.In the change of various types of wetland,except for river wetlands,the area ofother types of wetlands decreased,including marsh wetland.The area is reduced the most;in the composition of the structure,the lake wetlands account for an absolute proportion.From 1984 to 1996,lake wetlands were transferred to the largest area;from 1996 to 2006,a large number ofwetlands were converted to non-wetlands under the influence of climatic environment and human economic activities;from 2006 to 2015,grassland transferred into and out of the area At most,the reduction in wetland area has been alleviated.(2)Between 1989 and 2015,the total area of wetlands in the Alahu Group increased,with an increase of 368.5 km2.In the change of various types of wetlands,the area of river wetlands and natural ponds decreased,and the area of swamp wetlands increased the most and the rate of change In the composition structure,the lake wetland accounts for the largest proportion,always more than 60%;in the land use transfer matrix,the swamp wetland has the largest transfer area,and the reduction is larger after2006.(3)Between 1986 and 2015,the total area of the wetland in Dongting Lake continued to decrease,and the area decreased by 663.4 km2.In the change of various types of wetland,the area of mud beaches decreased the most,and the area of lake wetlands and river wetlands increased.The proportion of each type of wetland in the composition of the components has a large change;in the land use transfer matrix,the transfer area of farmland is the most.(4)Analyze the driving factors affecting the change of wetland area in each research area from two aspects: natural factors and human factors.The reduction of wetland area in Hulun Lake is the result of the combination of natural and human factors.The increase in the wetland area of the Alahu Group is the result of a single natural factor.The reduction of the wetland area of Dongting Lake is mainly affected by human factors,while the influence of natural factors only accounts for a small part.Among them,the natural driving force factors include temperature,precipitation,relative humidity,glacial area change,etc.The anthropogenic driving factors include the population,the area of cultivated land,the stock of livestock,the total value of production,and the per capita annual net income of farmers.