Background: Knowledge about vegetation and soil seed bank composition and the processes that contribute to vegetation recovery after the removal of heavy grazing is lacking in sub-alpine ecosystems. Aims: In order to assess the effects of large herbivores on above-ground vegetation (AGV) and soil seed bank (SSB) characteristics, intensively sheep-grazed areas were compared to adjacent areas where grazing had been removed 10 years previously in a sub-alpine grassland of northern Iran. Methods: A total of 40 4-m² (2 m × 2 m) plots were established in each treatment, and soil samples were collected from each plot within a depth of 10 cm. Plant species composition was determined for each plot during the flowering stage of herbaceous species in June 2011. The seedling emergence method was used to estimate SSB composition. Results: A total of 45 species (23 annuals and 22 perennials) emerged from the soil samples of the grazed area, while the number of species emerged from the soil samples of the previously grazing area was 76 (37 annuals and 39 perennials). The removal of grazing led to a significant increase in species richness and seed density in the SSB. Species turnover of AGV was higher, and that of the SSB was similar for grazed areas compared with areas that were formerly grazed. Detrended correspondence analysis ordination of AGV composition showed a clearly separate structure between grazed plots and plots where grazing has been removed, while the segregation was less clear for SSB composition. Conclusions: We concluded that restoration of locally degraded sites cannot rely on the SSB when grazing is stopped simultaneously and unvegetated gaps are colonised by vegetative growth rather than by seed.

Background: Understanding the role of livestock grazing on plant diversity can be improved by an accurate measurement of diversity at all hierarchical scales due to the changeability of diversity components in space. Aims: We evaluated the effects of grazing on plant species diversity at different scales of all common and rare species in two regions that have different climatic conditions (arid vs. semi-arid). Methods: In each region, we collected abundant data of plant species from a nested sampling design that consisted of local (80 plots) and regional (16 sites) scales. We partitioned total species diversity (γ) into within plots (α_l), among plots (β_l) and among sites (β₂) using the additive partitioning. Results: Diversity among sites contributed the most to total diversity for all and rare plant species in both regions. In addition, α₁ and β₁ diversities in ungrazed areas were greater than those in grazed areas for all and common species in both climates. Conclusion: Abandonment of grazing after 10 years resulted in significant regeneration of common species at the local scale, with no change in rare species. We conclude that low grazing intensity is likely to be an important tool for conservation of plant diversity in which all scales should be considered.

Background: Little information is available about the effects of different species of shrubs on the composition of the soil seed bank (SSB) and how the SSB could contribute to restoration of degraded grasslands. Aims: We determined the role of three dominant shrubs on SSB characteristics and evaluated their potential for their possible use in rangeland restoration projects. Methods: Ten sites, each containing three shrub species (Onobrychis cornuta, Berberis integerrima and Juniperus sabina) and a herbaceous patch (control) in close proximity, were sampled and their SSB density, richness and diversity were determined. Results: Density of the SSB at 0–5 cm depth was lowest under J. sabina and highest under herbaceous vegetation, but did not differ between B. integerrima and O. cornuta. SSB density at 5–10 cm depth was significantly greater under B. integerrima than under the other shrubs or herbaceous patch. Species richness of the SSB was significantly greater under B. integerrima at 5–10 cm depth than under the other shrubs. Conclusion: This study revealed that the extent to which vegetation affected SSB characteristics did not only depend on the presence of shrubs, but also on the species of shrub. We recommend B. integerrima as a priority species in restoration projects due to its significant positive influences on SSB.