The effects of fire on density, diversity and richness of soil seed bank in semi-arid rangelands of central Zagros region, Iran

Soil seed banks can play an important role in vegetation restoration after large scale disturbances, particularly after disturbances (e.g. fire) that create gaps in the vegetation structure. It examined the effect of fire on soil seed bank dynamics of Central Zagros rangelands in semi-arid region of Iran by analysis of seed content in sample layers at depths of 0–5 cm and 5–10 cm. The seedling emergence method was used to determine species composition of the seed bank. The results indicated that no significant change was evident in the species richness and diversity of the germinable soil seed bank, but the density of the germinable soil seed bank differed significantly among burned and unburned (control) sites. Similarity between the vegetation and the seed bank was low and no significant was observed in the similarity between the soil seed bank and above ground vegetation in fire with control sites. In the upper soil layer (0-5 cm), fire produced a significance decrease of density. In the lower layer (5-10 cm) the seed bank showed no significant effects of fire thus confirming the role of soil depth to reduce fire impact.