Analysis on the shrinking process of wetland in Naoli River Basin of Sanjiang Plain since the 1950s and its driving forces

Wetland is an important resource and it is the most suitable and important survivinge nvironment to human beings.Because of natural and anthropogenic influence,wetland is shrink ing extensively.Its function is declining.All these have threatened the sustainable development of human beings.Taken Naoli River Basin as an example,the wetland shrinkage in space and time and its driving forces are analyzed from 1954 to 2000.The results show that the area of wetland reduces from 1 149 878 hm2 in 1954 to 277 691.25hm2 in 2000.The percentage of area reduces from 45.85% to 11.07%.The area of wetland is only 1/4 of the original.On the other hand,the area of cultivated land increases from 206 003.5hm2 to 1 440 260.25hm2.The percentage of area increases from 8.21% to 57.43%.And the main driving force of wetland shrinkage in Naoli River Basin is the human activities reclamation.