Fig.1 Location and layout of sample plot in the three typical karst districts of southwest China. BB1 are in Beibei; YJ1 and YJ2 are in Yinjiang; and, YY1, YY2, and YY3, and YY3 are in Youyang. YY1 and YY2 belong to shrubland, BB1, YJ1, YJ2 and YY3 belong to woodland. Blue gird showed investigated units of vegetation, and red bounding box represent 2 × 2 m quadrats for measuring variables.