A Study on the Spatial-Temporal Dynamic Characteristics of the Marsh in the Sanjiang Plain, China

Using the methods of combining landscape ecology with GIS spatial analysis, this paper analyzes the dynamics of the marsh landscape structure in the Sanjiang Plain in the past 20 years, and further more, taking Fujin County, located in the north of the plain, as an example, analyzes the conversion between marsh and other land use types. It is shown that the marsh in the Sanjiang Plain decreased greatly in the past 20 years but the trend has begun to diminish. The marsh area decreased by 51.33% from 1980 to 1996, whereas it decreased by 4.19% from 1996 to 2000. The fragmentation of the marsh increased; the number of the patches increased by 326 from 1980 to 1996, whereas only by 18 from 1996 to 2000. It is obvious that the speed of increase in patches number was reduced and the marsh fragmentation decreased, which shows that the reclamation of the marsh converted from the fragmentation to the brim in a large area of the marsh. The reclaimed marsh has mainly been converted to paddy field and dry land. The centroid of the marsh moved from the northeast to the southwest on the whole, and the movement of the marsh's centroid from the eastern part to western part was quicker.