[Dynamics of salinization land based on EVI series data and landscape pattern analysis in Songnen Plain: a case study in Da'an City]

Abstract

The west part of Jilin Province is one of the most salinization regions in China and much attention has been paid to the dynamics and monitoring of the salinization land. Based on the land use data derived from TM images in 2000, 2005 and 2010 and the enhanced vegetation index (EVI) series data from 2000 to 2012 of Da'an City as a typical salinization region, we used landscape pattern analysis to elucidate the dynamics of salinization land, and used gray incidence method to analyze the main driving factors for the dynamics of land salinization. The results showed that the dominant land use types in Da'an City were cultivated land, grassland and salinization land. From 2000 to 2010, the area of salinization land and construction land showed an increasing trend, while that of grassland tended to decrease. Salinization land, which showed increased connectivity and integrity, was mainly transformed from grassland, swamp land and water area. Annual EVI values in Da'an City showed an overall increasing trend while the average values showed obvious spatial differences with the lowest EVI level in salinization land. From 2000 to 2012, the increment of vegetation cover area was larger than that of the degraded area. Landscape transformation affected the changing trends of EVI. Both natural factors and human activities affected the dynamics of salinization land, and human activities showed a greater impact on land salinization than climate factors.