| Wetland is an important ecological system on earth,it is in the land and aquatic ecosystem between the transition zone,is one of the important human living environment for human beings to provide a large number of material environmental resources.In the city,the wetland and the human relations are the most closely related.Since ancient times,the city has been built according to the water,and the urban development is inseparable from the urban wetland resources,which is the key to the survival and development of the city.However,with the acceleration of urbanization in our country,the urban economic development and urban population expansion have led to the blindness of urban wetland development,which has led to a significant reduction in wetland area,deterioration of water quality and deterioration of urban wetland function.Resource shortage and other issues.These problems seriously affected the urban ecological environment,reduce the livable level of urban residents,hinder the sustainable development of the city.Therefore,the study of urban wetlands is conducive to the systematic protection and construction of wetland resources,rational planning and utilization of wetland resources.For the improvement of urban ecological environment,promote social and economic sustainable development is of great significance.At present,urban wetland research needs to solve the following questions(1)how to divide urban wetland types.(2)the spatial and temporal changes of urban wetlands in space.(3)the characteristics of urban wetland landscape changes.(4)the driving force of wetland changes.Based on the above problems,this paper selects the TM remote sensing data of Chongqing in 1988,2000 and 2010,and summarizes the existing research results.Based on the geography,using RS and GIS technology,through visual interpretation,supervision classification,And then the urban wetland is divided into wetland,lake wetland,reservoir pond,tidal flat,paddy field wetland,and landscape ecology is used to study the wetland of wetland,,The statistical theory of Chongqing metropolitan areafrom 1988 to 2010 wetland landscape pattern changes were analyzed.The main conclusions of this paper are:(1)Using the decision tree method to extract the remote sensing data of Chongqing in 1988,2000 and 2010 respectively.Extracted,rivers,lakes,paddy fields,tidal flats,reservoir pond 5 this type of urban wetland.Respectively,to extract the three Chongqing urban wetland types of remote sensing data for accuracy evaluation.The overall accuracy of the three data is 70.75%,73.28%,74.33%,kappa coefficients are0.72,0.78,0.76 respectively.The results show that the decision tree classification extraction method is suitable for urban wetland research(2)The wetland area of Chongqing metropolitan area decreased from 1988 to 2010.The area of wetland in Chongqing metropolitan area decreased by 212.79 hm2,and the reduction rate was 12.27%: the wetland of the river decreased by 966 hm2 and the reduction rate was 7.8%.The area of the lake wetland in the urban area also showed a decreasing trend of 6.9 hm2 and a decrease of 9.3% Wetland increased slightly,compared with 1995 increased by 16 hm2,but the increase is not significant: the reservoir pond type a total reduction of 82 hm2,the reduction rate compared to other wetland type minimum,the reduction rate of 4.5%: paddy wetland area to reduce the most,reduce the range maximum.(3)The wetland type structure analysis of Chongqing metropolitan area shows that the wetland change is the most stable,indicating that the influence of human factors is relatively small.The shape boundary of the reservoir pond is becoming more and more regular,the complexity of the boundary is reduced and the man-made influence is bigger.Paddy field,lake wetland change is most obvious.The results show that the wetland has the greatest influence on human factors.And the paddy field wetland changed the most,which was the most obvious change type of urban wetland.(4)The wetland landscape pattern of Chongqing metropolitan area showed that the number of patches and plots of wetland landscape showed a gradual increase trend from1988 to 2000.And after 2000 there was a slight decline.The average plaque area showed a downward trend year by year.Indicating that the wetland landscape fragmentation and spatial heterogeneity intensified.The index of expansions decreased year by year,the degree of fragmentation increased year by year,and the connectivity of wetland landscape decreased.And the overall concentration of wetland landscape is not high,relatively scattered.The fractal dimension index increases year by year,the landscape shape is complex and the boundary is irregular.The wetland landscape leveluniformity index of Chongqing has little change,and the aggregation degree of landscape type is not high.Diversity index,the first increase after the trend of decline.(5)the natural factors and human factors in two aspects of Chongqing urban wetland dynamic change driving force analysis,summed up the driving force influencing factors: human factors,natural factors,supplemented by the impact of the mechanism,leading to Chongqing urban wetlands Area reduction,wetland landscape change.And put forward the protection measures of urban wetland monitoring mechanism and wetland protection red line. |
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