Majority of Sub-Saharan Africa land mass is rangelands. However, rangelands are globally degrading rapidly, affecting the soil seed bank (SSB) of native plants, and, therewith, the long-term resilience towards environmental and human-induced pressure on the ecosystem. We investigated SSB in communally and seasonally enclosed (SE) grazing areas as influenced by sub-habitats of mature trees of Acacia tortilis and Acacia senegalin east Shoa zone of Ethiopia. Herbaceous vegetation data (above ground and SSB) were collected from different sub-habitats. Mean percentage composition of perennial grasses in above ground vegetation was higher by 76.18% in SE than in communal sites while the opposite was true in the case of annuals/short lived perennial grasses. The density of grass and total seedlings m-2 in SSB of SE (grass = 547.50±40.92; total seedlings = 671.00±46.35) was higher (P<0.001) than in communal sites (grass = 364.09± 24.25; total seedlings = 518.06±31.07) while no significant difference was observed for tree species. In three sub-habitats, Chloris pycnothrixwas most frequent speciesin the SSB while in five sub-habitats, Dactyloctineumaegyptium was most common. Thus, proper grazing management; i.e., resting, particularly during the growing season and preservation of Acacia species is essential for grazing land recovery and resilience.
Keywords: Ecosystem, arid-semiarid, grazing management, sub-habitat