Variation of soil seed bank characteristics under the shrubs
The ANOVA results showed that the highest and lowest values of SSB densities were found under A. scoparia (1133 seeds /m2) and control (110 seeds /m2), respectively (df = 3, F = 3.56 and p<0.05) (Fig. 3). The highest and lowest species number of SSB were observed under E. stellata (8.26 species per samples) and control (3.13 species per samples), respectively (df = 3, F = 6.41 and P<0.01) (Fig. 4). In addition, the results showed that the highest and lowest values of Shannon-Wiener diversity index were observed beneath of E. stellata and control with 1.06 and 0.83, respectively (df = 3, F = 3.32 and P<0.05) (Fig. 5). The highest and lowest values of Simpson diversity indices were found under canopy of E. stellata (0.75) and the control (0.44), respectively (df = 3, F = 5.02 and P<0.01) (Fig. 5). The highest values of similarity between SSB and AGV were found under three shrubs (18% to 19%) and the lowest was observed in the control (8%) (df = 3, F = 15.11 and P<0.01) (Fig. 6).
In addition, the mean surface of shrub canopies on ground was ca. 7.5 m2, 5.5 m2 and 4.00 m2 for A. scoparia, D. mezerum and E. stellata , respectively, and amongst three shrubs, A. scopariahad the highest mean height with ca. 3.5 m comparing with D. mezerum and E. stellata with ca. 2.60 m and ca. 1.83 m, respectively