Shrub effects on germinable soil seed bank in overgrazed rangelands

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.

We determined the role of three dominant shrubs on SSB characteristics and evaluated their potential for their possible use in rangeland restoration projects.

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.

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.

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.