Abstract:

The Comprehensive and Sequential Classification System （CSCS） classifies vegetation types based on a two-dimensional coordinate map of seven thermal zones （Ⅰ-Ⅶ） and six humidity zones （A-F） to give 42 classes （ⅠA-ⅦF） and was originally developed in China for classification of diverse grasslands based on environmental factors. Grassland is an important part of the terrestrial ecosystem. The precise definition of grassland types is of great significance to the study of grassland resources. This study focused on montane grasslands in China and used the Digital Elevation Model （DEM） to quantitatively assess the areas of montane subclasses in China， identify grassland subclasses and analyze the spatial distribution characteristics of the subclasses. It was found that： 1） Based on criteria of relief and altitude， 20 montane subclasses were identified. The subclasses with the most extensive distribution area were mainly those of low relief. The distribution area of hilly and intermediate relief montane subclasses was similar， while the area of subclasses of high and extremely high relief was less. 2） Due to the spatial differences of water and heat conditions in mountainous areas， some grassland subclasses do not exist in particular environments. 3） At the CSCS class level， most widely distributed subclasses was frigid perhumid rain tundra alpine meadow （ⅠF36）； cold temperate perhumid taiga forest （ⅡF37） is the second； warm-perhumid deciduous-evergreen broad leaved forest （ⅤF40） is ranked third and subtropical-extrarid subtropical desert （ⅥA6） had the smallest distribution area. The research results provide an objective scientific basis for the development and utilization of grassland， cultivation， protection and management policies， and the formulation of sound animal husbandry practice.

Key words: Comprehensive and Sequential Classification System of grasslands （CSCS）, montane grassland subclasses, spatial distribution characteristics