Dynamic Monitoring And Analysis Of Populus Euphratica In The Upper Reaches Of The Tarim River

Accurately Grasping the Dynamic Characteristics of Populus euphratica and Protecting the Populus euphratica Ecosystem in Tarim River,it can provide basis for decision-making in typical regions to address climate change and promote regional peace and stability.It is of great significance to promote the sustainable development of the social economy and the strategy of the Belt and Road Silk Belt.Based on Landsat TM/OLI from 1990 to 2015,GLASS LAI from 2002 to 2014,and MODIS LAI from 2016,the research uses object-oriented classification algorithm and dynamic threshold method to extract the area distribution and key phenology of Populus euphratica.using GIS technology to analysis the spatio-temporal characteristics and Phenology of Populus euphratica,and the analysis of the driving factors that caused the changes in the spatial pattern of Populus euphraticas.The main research results are as follows:1?The object-oriented classification method was used to extract the distribution area of Populus euphratica.Based on the land use degree change index,transfer matrix,landscape index and field survey results,dynamic monitoring and analysis of the temporal and spatial pattern change of Populus euphratica in the upper reaches of the Tarim River was carried out:in the 1990-2015 years,the area of Populus euphratica decreased by 2260.45 km~2,showing a tendency of continuous decrease,and transferred 1803.04 km~2,1855.60 km~2,1340.40 km~2 to other forest land,cultivated land and unused land respectively;the structure of Populus euphratica community on the time series tends to be simple.As a result,Populus euphratica showed a decline and decline,and the Populus euphratica ecosystem was gradually degraded;the individual growth of the Populus euphratica gradually decreased along the direction of the main axis of the river,but the spatial distribution of the Populus euphratica gradually increased,the spatial connectivity gradually increased,and the degree of separation gradually decreased2?The Savizky-Golay filtering method is used to denoise the remote sensing data,and the paper extract the phenological period of the typical sample point of the Populus euphratica in the upper Tarim River through the dynamic threshold method.It can be concluded that the beginning of the growth season of the natural Populus euphratica in the upper reaches of the Tarim River in the 2002-2016 years was postponed,and the annual average was delayed about 1.3 days,presenting the spatial pattern of both ends of the river earlier than the middle.The end of the growing season of the Populus poplar was about 0.6 days in advance,and the length of growth season was shrinking.The trend of reduction is about 1.9 days per year,showing a spatial pattern in which both ends of the river are longer than the middle.3?Based on the extracted area distribution and phenology of Populus euphratica,the driving force analysis of temporal and spatial pattern change of Populus euphratica and phenology was carried out.It can be known that the microclimate in the upper reaches of the Tarim River shows a trend of“cold-wet-warm-dry”,and the meteorological factor and the reduction of the area of Populus euphratica are direct.The rapid increase in population and GDP indirectly undermined the ecological balance and security of Populus euphratica ecosystem.Temperature was a key factor affecting the phenology period of Populus euphratica,and the mean temperature in February and February was significantly negatively related to the beginning of the phenology growth season of Populus euphratica.The average temperature during July-September had a significant positive correlation with the length of the growth season and the growing season of Populus euphratica.The increase in temperature was earlier than the beginning of the growing season of Populus euphratica,but the growth period and the end of growth period were delayed.