Decadal to centennial land use and land cover change (LUCC) has been widely recognized as an integral component and important driver of global environmental change. LUCC could make a huge impact on a number of cascading biogeochemical progresses. Therefore, better understanding and quantification of past spatiotemporal changes in land use and land cover is significant in promoting sustainable use of land resources, especially in ecologically fragile regions. As the largest freshwater marsh in China, the wetland in Sanjiang Plain is vulnerable to global change and human disturbance. High-intensity human activities have lead to intensive land use and land cover change in this region. Previous studies mainly use a bitemporal detection method to analyze the categorical changes of land cover. To improve our understanding and get more accurate estimation of the LUCC process in this region, we used trajectory analysis as well as relative land use suitability index (R), the Lorenz curve and Gini coefficient to analyze the land use change from 1954 to 2013 in Sanjiang Plain based on a five-stage land use data and made preliminary estimation of the role of human activity in the environmental change.
Our results indicated that Sanjiang Plain experienced significant land-use change in the last 60 years. More than 60% of original wetland transferred to cropland while less than 30% was preserved. Paddy land and dry land increased by 15.99% and 22.46% respectively at the expense of wetland (23.48%) and grassland (9.48%). Settlement and water bodies were relatively stable in terms of coverage and spatial distribution, while wetland, grassland, and forest land had weak stability in Sanjiang Plain. Human activities played an important role in those changes.