Evaluation of soil seed bank (SSB) in relation to biotic environmental factors could be important in degraded areas, since SSB is one of the major sources that facilitates the recovery of degraded plant communities after disturbances such as grazing, flooding and drought. The aim of this study was to investigate the role of Astragalus myriacanthus and Acantholimon spinosum on SSB characteristics. Soil sampling was carried out in four different positions (upslope edge, downslope edge, center and outside) of each cushion in semiarid mountainous regions in Iran. Then, SSB composition and density, species diversity and richness of SSB in each position were estimated using the germination method. The results of the nonmetric multidimensional scaling showed that the separation of species composition of SSB in four different positions was not possible in any of the cushion species. Nevertheless, the results indicated that the lowest of SSB density, species diversity and richness were observed in the outside of the two cushions. In both cushions, A. myriacanthus and A. spinosum, the mean SSB density (1,606.4 and 646.5 seeds/m2, respectively) was significantly higher in the upslope edge. Totally, the mean density of SSBs in A. myriacanthus (903.6 seeds/m2) was significantly higher than that of A. spinosum (360.6 seeds/m2). We concluded that the cushion plants can act as seed traps and therefore could facilitate recovery of degraded sites in the steep‐hilly areas, while, the possibility of seed penetration into the soil of different directions of cushion might be significant.

Little information is available about the effects of different species of shrubs on the composition of the soil seed bank (SSB) in the semiarid regions. We determined the role of three dominant shrub species on SSB characteristics and evaluated their potential for their possible use in rangeland restoration projects. Fifteen sites, each containing three shrub species (Amygdalus scoparia, Daphne mezereum and Ebenus stellata) and a herbaceous patch (control) in close proximity, were sampled and their SSB density, species richness and diversity at 0–10 cm depth were determined. The results showed that the density of the SSB was highest under A. scoparia and lowest in the control. The highest SSB density of grasses was found under A. scoparia, while the highest SSB density of forbs was found under E. stellata. Species diversity of the SSB was significantly greater under E. stellata than under the other shrubs and control. This study revealed that the extent to which shrubs affected SSB characteristics did not only depend on the presence of shrubs, but also on the species of shrubs. These different roles of different species of shrubs on SSB are advised to be considered in the restoration of degraded areas through the SSB in the semiarid areas. In the case of changing management type from intensive grazing to extensive grazing or non‐grazing, the role of different shrub species in the conservation herbaceous species through their SSB can be different.

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