Comparison of soil seed bank and above ground floral composition between three land-use types of Arsi-Bale Massifs in Southeast Ethiopia

Abstract

The aim of this study was to determine the floristic composition, diversity, density of soil seed bank, and relationship of soil seed bank and above ground vegetation in forest patch, riverine and grazing lands of Arsi-Bale Massifs of Southeast Ethiopia. Soil samples were collected from 56 plots of 10 cm x 10 cm quadrats size from four layers (litter layer, 0–3 cm, 3–6 cm and 6–9 cm). Regarding above ground vegetation, 30 m x 30 m for trees, 5 m x 5 m for shrubs and 1 m x 1 m quadrat sizes for herbaceous were used for sampling from the same 56 plots. Shannon-Weiner diversity index was used for soil seed bank and above ground vegetation. Similarities among the land use types, soil seed bank and above ground vegetation were analyzed using Jaccard coefficient of similarity (JCS). Variance analysis of species abundance in each soil layer and land use types was done by ANOVA using SAS software (Version 9.0). A total of 292 vascular plant species from standing vegetation and 107 species from soil seed bank were identified. A total of 10,828.57 seedlings per m² with mean density of 34.27 ± 7.79 individuals/m2 was recorded. The mean density of soil seed bank among the soil seed bank layers did not show significant difference (one-way ANOVA, (F3, 316) = 0.13, P<0.94). The Jaccard’s similarity index value between the soil seed bank and above ground flora show the highest dissimilarity (JC = 0.22). The species composition, diversity and seed density in grazing land use type was lower than other land use types. Generally, only small number of above ground plant species were represented in the soil seed bank.