Investigation of soil seed bank composition in boundary and interior of forest habitat (case study: Vaz watershed in Mazandaran province)

This study aimed to compare soil seed bank characteristics (density, species diversity and similarity with above ground vegetation) between the boundary and interior of forest habitat. Boundary and interior of forest habitat were different in term of the cover percentage of woody plants. Therefore, the zone between forest and rangeland was selected as non-dense forest (Ecotone) with less cover percentage of woody plants and the interior of forest adjacent to the ecotone was selected as dense forest habitat with higher cover percentage of woody plants. In each habitat, seven transects were established with 25 m distance between transects. Then, soil sampling was done using quadrates in two depths: 0-5 and 5-10 cm. After the chilling treatment, soil samples were transferred and spread in the greenhouse. Germinated plant species were identified, counted and then removed. On the other hand, the percentage cover of plant species in each plot was recorded in the growth season. Finally, the number of seeds germinated in the greenhouse was recalculated per square meter and then the similarity between seed bank and aboveground vegetation was calculated in each plot using Sorenson’s similarity index. Non-paired t-test was applied to compare soil seed bank characteristics between the two depths and between the two habitats. The results showed that seed density and species diversity were significantly higher in the ecotone than the dense forest. The density and species diversity of soil seed bank was significantly higher in the upper layer than the deeper layer. There was low similarity between soil seed bank and aboveground vegetation in the both habitats. However, the similarity between seed bank related to upper layer was significantly higher in the dense forest than the ecotone. It can be concluded that ecotone zone has more enrichment from interior part of the forest due to more open crown cover, position and more species diversity.