The rapid spread of Stellera chamaejasme L. (Stellera) often causes serious damage to grassland habitats, and limits the development of animal husbandry. Up to the present, the investigation has been limited to the description of the area where Stellera occurred. However, few studies have foucued on its density which is more representative to show the situation of the grassland degradation, and also provide guiding significance to chemical control. Two methods of the coverage estimation including fi...