Spatial autocorrelation analysis of multi-scale changes in Bielahong River basin wetlands

The multi-scale dynamic change in the Bielahong River basin wetland of the Sanjiang Plain is studied using a spatial autocorrelation model and the geographic information system (GIS) technology.Results show that the wetland area was gradually decreasing and the spatial auto correlation of the entire wetland area exhibited an up-downup pattern during the period 1950s-2000.A downward trend is detected in the high-high autocorre lation type, which tends to spread toward the lower reach of the Bielahong River basin.The opposite result is obtained for the lowlow autocorrelation type.The wetland spatial autocorrelation exhibits an appreciable scale effect, as the spatial autocorrelation increases with the increase of smiulation scales.The result indicates that the dynamic change of wetland spatial autocorrelation is mainly caused by human activities.The spatial autocorrelation analysis of wetland changes can reveal the regularity of the wetland spatial cluster as well as the dynamic changes of the wetland spatial correlation pattern, which could be one of the effective approaches to study ing the spatial heterogeneity of wetlands.This study provides a scientific basis for wetland classification and decision-making management.