The effect of pit and mound landscape and canopy gap on flora, Life form and chorology of vegetation and soil seed bank (case study, mixed European hornbeam forest)

This study was carried out to investigate the effect of pit, mound landscape and canopy gap on floristic characteristics of vegetation and soil seed bank of mixed European hornbeam (Carpinus betulus) forest in Astara city. Sampling of vegetation and seed bank was carried out in pit and mound positions of different ages and gap with different area and also under the closed canopy). The results showed that there are 32 species belonging to 24 families and 28 species belonging to 23 families in vegetation and soil seed bank respectively. Results also showed that phanerophytes and hemicrptophytes were the dominant life forms constituting the above-ground vegetation of middle land and highland and in both physiographic positions, the creation of gap has led to the overcoming of the phanerophytes. In the seed bank, the dominant life form was not influenced by altitude and therophytes and hemicrptophytes were the most important life form of both altitude classes. In the soil seed bank, the change of species life form in each altitude is associated with the creation of canopy gap, pit and mound. The number of therophytes increased in the middleland with the creation of canopy gap (especially> 200 m2) and the pit and mound. In term of geographical distribution, Irano-Turanian/Euro-Siberian/Mediterranean chorotype was a major component of both altitude classes in soil seed bank, while Euro-Siberian chorotype was a main component of both altitude classes in above ground vegetation and its change was influenced by pit and mound and canopy gap size.