Role of Plant Patches in Preserving Flora from the Soil Seed Bank in an Overgrazed High-mountain Habitat in Northern Iran

Seed bank is a central topic for plant community restoration. We determined the potential and regeneration capacity of soil seed banks of woody plant patches in conservation of the vegetation in an alpine habitat, since vegetation has completely disappeared in some sites by intensive grazing in the habitat. The study was done in mountainous area of Alborz in Iran. A total of ۲۰ individual shrubby patches were selected and two quadrats were established in and out of each patch. Soil samples were then collected from each quadrat in spring, ۲۰۱۱. Above-ground vegetation was estimated in each quadrat in the growing season. The soil seed bank was determined by Seedling Emergence method in the greenhouse. The results showed that the soil seed bank density inside the shrub patches was much higher than outside the patches. This differentiation was more pronounced for forbs. However, seed density of the between-patches was strongly correlated to seed density of the within-patches, indicating the so-called patch effect. Similarity between the soil seed bank and aboveground vegetation was lower inside the patches than outside. This study revealed that the limited woody patches that have remained in the study area could play an important role in conservation of herbaceous and palatable species by their positive effects on the aboveground vegetation and the soil seed bank.

Keywords:

Alpine grassland , Nurse plant. Palatable species , Patch effect , Seed dispersal