Research On The Landscape Pattern Change Of Alluvial Plain Under The Background Of Urbanization

Dujiangyan city was the alluvial plain;its landscape pattern was easy to affect by human activities,reveal the changes of landscape pattern under urbanization can help to the urban environment construction.Take Dujiangyan as a study area,base on the remote sensing image in the years of 1995,2007,2014,to get the landscape pattern information.And give a analysis for the characteristicsand changes of landscape pattern;Give a analysis between the urbanization process and the evolution of landscape pattern;Use the Valuation method of ecosystem service value,to evaluate the ecological effect of landscape pattern evolution.The results are as follows:(1)The composition and changes of land coverForest and Farmland were the main landscape types in Dujiangyan.The land cover changed greatly in 19 years,the area of farmland decreased significantly.The area of Residential area and mining,Traffic were increased significantly.The dynamic attitude between 2007 and 2014 was 2.09 times of that in 1995 ~ 2007.(2)Landscape pattern characteristics and changesthe overall landscape fragmentation increased and the landscape heterogeneity was enhanced in 19 years,the dominant types increased.The land cover type is more abundant and the proportion presents a balanced development trend;the patch shape tended to be irregular,the aggregation degree of the same nature plaque decreases under human disturbance,and the intensive trend of different types of patch is strengthened.There are more types of change:Traffic,Residential area mining industry,Farmland.(3)The relationship between urban expansion and landscape patternThe increase of urban population and construction land has significant impact on the change of landscape pattern.The impact of urbanization on landscape fragmentation and diversity was greater than on landscape element area and spatial configuration.(4)The ecological effect of landscape pattern evolutionForest with the highest service value,water conservation was the most prominent ecological service.The total ecological service values of Dujiangyan city decreased by 629.46 million Yuan.In addition to the value of ecological services of water body with a growth of average annual average 2.6%,the others showed a different degree of decline.The evolution of landscape pattern was directly related to the increase and decrease of landscape cover,and various construction activities were the main reasons for the transformation.The area change of the regional ecosystem directly affects the function of ecological services.It is suggested that,the urban development should be carried out under the premise of conservation of ecological land(forest,farmland).At the same time,reduce the occupation of farmland,forest under the population growth and urban expansion.