Analysis on Wetland Shrinking Characteristics and Its Cause in Heilongjiang Province for the Last 50 Years
黑龙江省近50年来沼泽湿地退缩特征及其原因分析

Based on RS and GIS technology,the paper studied the spatial characteristics of marsh change in Heilongjiang Province and analyzed the influence of human activities on marsh.What's more,we knew of the spatial characteristics of marsh in the field of administration planning.The authors reconstructed spatial data of wetlands from 1954 to 2000 by integrating topographic map in 1954 and TM image in 2000 in Heilongjiang Province.Furthermore,combining patch centroid change model,landscape parameters and Euclid shortest-path function,we analyzed marsh shrinking characteristics and regularity of regional differentiation,and further discussed the cause of marsh shrinking in the perspective of the impact of human activities on marsh shrinking.The results showed that: area of wetlands had dramatically decreased from 7.914 million ha to 3.035 million ha in Heilongjiang Province for the last 50 years;in general,the centroid of marsh moved to the northwest of Heilongjiang Province,which showed that marsh shrinking maily occurred in the northeast;marsh landscape went to fragmentation;the shrinking areas were mainly concentrated in the Sanjiang Plain,Songnen Plain,Da Xing'an Mountains and Xiao Xing'an Mountains.There are three major humanity reasons which led to marsh shrinking: population growth and constant land reclamation;farm development policy of building state farm;and the spatial relationship between wetland shrinking and major highways.