Changes in rangeland cover associated with livestock grazing in Altun National Nature Reserve, northwest Qinghai-Tibetan Plateau

摘要

The Altun National Nature Reserve, located on the northern edge of the Qinghai-Tibetan Plateau of China, is one of 35 most important biodiversity sites worldwide. Land-use and cover change are affecting this alpine ecosystem. A supervised classification was used to classify types containing meadow, steppe, sparse rangeland, and non-rangeland environments based on Landsat Thematic Mapper (TM) imagery data. By conducting an aggregation analysis using a Geographic Information System an analysis of changes from 1990 to 2010 was conducted. The results demonstrated that sparse rangeland was the most widespread vegetation type and underwent significant changes over the period. The area of sparse rangeland increased by 64.4km(2) from 1990 to 1995 and by 49.3km(2) from 1995 to 2000. However, the area of sparse rangeland decreased by 99.2km(2) from 2000 to 2005 and by 247.4km(2) from 2005 to 2010. The major areas of change were primarily located in the vicinities of the Yishakipati central inspection station, the Kardun inspection station, and Ayakkum, Aqqikkol and Jingyu Lakes. There was a positive correlation between the change in area of sparse rangeland and the amount of livestock grazing. The change in non-rangeland was significantly negatively correlated with the amount of livestock grazing during the period in the grazing area. Appropriate livestock grazing may be essential for promoting the resilience of the predominant ecosystems and key habitats of wildlife in the Altun National Nature Reserve.