Abstract:

On the basis of the “Atlas of China vegetation" compiled by the “China Vegetation Atlas Editorial Committee of the Chinese Academy of Sciences,we had applied the Geographic Information System (GIS) ARC/INFO (NT version) and digitizer to extract Haloxylon desert vegetation information and draw a special topic map of the geographic distribution of Haloxylon desert vegetation.On this basis,we had analyzed the community type,distribution pattern and patch character of Haloxylon desert vegetation.At the same time,according to the survey result of Haloxylon desert vegetation structure in recent years,we had undertaked preliminary evaluation of Haloxylon desert vegetation resources.The result showed that the total area of existing Haloxylon desert vegetation is 114 000 km², the distribution area in Xinjiang was the largest,accounting for 73.1% of total national Haloxylon desert vegetation,then followed by Inner Mongolia,accounting for about 14.1% of the national total;the distribution areas of existing Haloxylon desert vegetation in Qinghai and Gansu provinces accounted for 7.9% and 4.9%,respectively.The area of different Haloxylon desert vegetation types is also different, the area of Haloxylon ammodendron gravel desert accounted for 37.3% of the total area of Haloxylon desert vegetation;The area of H.ammodendron desert accounted for about 21.3% of the national total;The area of H. persicum accounted for 23% of the national total;And other types of Haloxylon desert community accounted for 19.4% of the national total. In China the Haloxylon desert vegetation located at: 107.6—77.3°E, 47.4—36.1°N. The altitude of vertical distribution was between 87～3 174 m.In the east and south borders of the Haloxylon desert vegetation distribution area,the major Haloxylon desert community type is H.ammodendron gravel desert while in the west and north borders,the major community type is H.ammodendron desert.The patches consisted of Haloxylon desert vegetation is 180 in China.The characters of the patches are many small patches, fewer large patches,with area of patches among patches was different by a big margin and the distance between most patches was fairly distant.According to actual survey result in recent years,although the distribution area of Haloxylon desert vegetation in China is very large,yet its coverage was in general fairly small,with an area of less than 30% coverage accounting for 70% of the total area of existing Haloxylon desert vegetation.

Key words: Haloxylon desert vegetation, geographic distribution, patch character, vegetation coverage