Comparing the vegetation and soil seed bank in six vegetation types of lowland rangelands in Behshahr, Mazandaran province

The soil seed bank condition is relatively responsible for variations in rangeland vegetation dynamics. Investigation on soil seed banks is very important where native ecosystems have been converted to other land uses substantially and the size of natural ecosystems are declined. The aim of this study was to evaluate the presence of species in vegetation and soil seed banks in six vegetation types of Behshahr lowland rangeland in Mazandaran province. Vegetation was sampled in 1 m2 plots along 100 m transects. Soil samples were collected from 0-5 cm and 5-10 cm of soil surface. Soil samples were put in germinating pots in the greenhouse and the numbers of seedlings were then counted. Vegetation similarity with soil seed bank was measured using Mantel test and Sorenson index. Results showed that the number of species in vegetation and soil seed bank varied based on the vegetation types. The Halocnemum strobilaceum- Juncus maritimus vegetation type contained 34 species (the greatest number of species recorded between the vegetation types). Twenty six species were also identified in the soil seed bank of Juncus maritimus vegetation type (the greatest number of species in the soil seed bank). Therophytes were the most frequent life form in both vegetation and soil seed bank pools with 31 and 25 species, respectively. Fifteen plant families were found in both vegetation and soil seed banks. The species from Poaceae and Compositae families were dominant in vegetation types but the species from Poaceae and Leguminosae were dominant in soil seed bank. Diversity and richness indices in vegetations were significantly greater than that in seed banks except in Salicornia europaea-Spergularia marina vegetation type. There was no similarity between vegetations and soil seed banks in the whole region and all vegetation types except in Aeluropus littoralis vegetation type.