| Popis: |
The Tarim River Basin,especially the downstream area of it is one of the ecologically fragile areasin China.Based on technologies of multi-type,multi-temporal remote sensing imagery,key ecological elements,that is,cultivated land changes in whole Tarim River Basin,the vegetation,sandy and salinized desertification in the green corridor zone of Tarim River mainstream were monitored from 1999 to 2008,after the implementation of comprehensive harnessing engineering for the whole Tarim River Basin.The investigation results show that the ecological environment in the green corridor zone of Tarim mainstream was conspicuously improved,mainly appearing as the rise of vegetation cover rate,the reduction of sandy desertification land area and the weakening of intensity of sandy and salinized land.On the other hand,the cultivated area in the Tarim River Basin significantly increased from 1999 to 2008,which reached 40.34×10 4 hm 2,for 24.13%.Among the whole basin,the cultivated area of the mainstream area increased most quickly.The growth rate of cultivated area of whole basin from 2004 to 2008 is significantly higher than those of the two periods from 1999 to 2002 and from 2002 to 2004.Moreover,the characteristics of sandy and salinized land in upstream of the main channel showed an increase in area of 2.69×10 4 hm 2 and a reduction in increase rate from 2002 to 2004.And sandy desertification land area decreased 1.20×10 4 hm 2 in the same period in lower reach of the basin.Vegetation cover rate of the whole basin apparently increased,especially the surrounding area of the Taitema Lake.Although the ecological environment presented an somewhat improvement after the implementation of comprehensive harnessing in the whole basin,the ecologically fragile environment need long-term supply of water resource and continuous concern from the whole society.The increase of irrigation water resulting from the substantial increase of cultivated area could undertake a long-term potential restraining effect on the harnessing of ecological functions of the Tarim River. |
