Analysis of the land degradation pattern in Zoige Plateau Marsh Wetland Based on MODIS data

Wetland ecosystem is one of the world´s most threatened ecosystem types. As the largest distributing center of highland peat swamps in the world, the conspicuous wetland degradation in Zoige wetland has become the focus of attention at home and abroad. To master the basic rule of land degradation in recent years in Zoiger wetland, this article first downloaded the MODIS-NDVI data (MOD13) from 2001 to 2013, which were used to obtain the yearly maximum NDVI by the method of MVC followed by a 3-year running mean. After this, the vegetation cover set was obtained based on which we got yearly land degradation data from 2002-2013. Zoige wetland land degradation types were divided into five types: extremely, heavily, moderately, lightly degraded types and non-degraded type. Finally, this paper analyzed the distribution pattern and its dynamic changes of land degradation process in nearly 10 years respectively from the patches and the landscape level. The following conclusions were obtained from this paper: (1) The vegetation coverage in this area was high as a whole. The medium coverage in the study area decreased while the closed vegetation increased in recent years. (2) The land degradation most belonged to lightly degraded type. However, the land degradation aggravated in parts of the study area because of the decreased lightly degraded land and the increased heavily degraded land. (3) The degradation experienced two opposite process with a turning point in 2008. The land degradation became more seriously and the whole landscape more complex. The deterioration was halted to some extent in the subsequent stage. Although the situation was somewhat worse than that at the beginning, the ecological environment treatment had given initial results.