Soil Seed Bank Flora Assessment in Relation to Acacia Species

The book addresses seed bank species composition, density, diversity, richness and life form, as well as soil chemical properties and texture that were examined under two habitats (canopied and un-canopied) along depth gradients (0-3 cm, 3-6 cm and 6-9 cm) relative to three encroaching acacia species (A. mellifera, A. drepanolobium and A. brevispica) in southern Ethiopian semi-arid Borana rangelands. Within all study sub-habitats of each acacia, there were more grass species than the non-grasses, except under the canopy of A. mellifera and the open area of A. brevispica. There was more species diversity under the canopies of each study bush. C:N ratios were lower under the canopies compared to the corresponding open areas in each study bush. This might be attributed to high amount of nitrogen under the canopies compared to the open areas due to under-canopy soil enrichment. Generally, this study indicated that the study acacia species improved their under-storey vegetation production and soil fertility. This implies that if properly managed, the study bushes can contribute to better livestock production in semiarid areas.