diversity means the diversity between two communities,which is often used to analyze the gradient variation on environment.It reflects species replacement along environmental gradient,and it is more useful while there exists obvious ecological gradient in the research region.Changbai Mountain is very famous for its obvious altitutional vegetation type such as broadleaved Korean pine forest,dark coniferous forest,Ermam's birch forest,and tundra on the north slope.In this research,an altitutional treasect was...