A GISbased integrated orderly classification system of grassland in Gannan region

Grassland is the basis of the livestock industry. Scientific and reasonable method of grassland classification is essential for the development, protection and management of grassland. Based on meteorological information in 30 years from 55 meteorological stations located within Gannan Region and in surrounding areas, the spatial databases of 0 ℃ annual accumulated temperature and humidity grade were constructed with the methods of geostatistics and mathematical regression. A potential grassland type map in Gannan Prefecture was made according to the method of Integrated Orderly Classification System of Grassland (IOCSG). The result of this study showed that 9 classes of grassland types were identified in the study area, including frigid perhumid rain tundra, alpine meadow class, cold temperate perhumid taiga forest class, cool temperate perhumid mixed coniferous broad leaved forest class, cool temperate humid forest steppe, deciduous broad leaved forest class, warm temperate perhumid deciduous broad leaved forest class, warm temperate humid deciduous broad leaved forest class, warm temperate subhumid forest steppe class, warm temperate semiarid warm temperate typical steppe class, warm temperate arid warm temperate zonal semidesert class. This study suggested that grassland mainly distributed regions within the elevation between 3 000 and 4 000 m, and the elevation and slope significantly influenced spatial pattern of grassland.