Seed bank structure in semi-steppe rangelands of West Azerbayjan Province

Soil seed bank is one of the main components in the dynamics of vegetation, the study of which can provide important information for the management, reclamation and improvement of rangeland vegetation. In the study of seed bank structure, important issues such as species diversity and seed density and their changes in different soil depths, similarity with aboveground vegetation and also the relationship between seed size and shape with its persistence are discussed. In the present study, the structure of seed bank was investigated in the semi-steppe rangeland of Qushchi in the north of Urmia city, West Azerbaijan province. Soil seed bank sampling was carried out in September in 20 plots of one square meter that were implemented on four transects at two depths of 0-5 and 5-10 cm. The soil seeds were identified and recorded using seedling emergence method and matched with the area's flora. According to the results, the density of the soil seed bank decreased significantly with increasing depth (70 seedlings at surface depth and 35 seedlings at the depth of 5-10 cm). At both depths, the highest abundance of seedlings was related to Bromus tectorum (31 seedlings at surface depth and 14 seedlings at the depth of 5-10 cm). Also, the persistence of seeds in the soil seed bank depends on the size and shape of the seeds, so that the seeds of the Poaceae family, due to their needle-like and elongated shape, had less displacement and therefore had higher density in the seed bank. Therefore, it is necessary to be aware of the diversity of seed banks in the programs of protection and restoration of rangelands, especially in the arid ecosystems of the country.