Species composition and diversity of small Afromontane forest fragments in northern Ethiopia

摘要: In the highlands of northern Ethiopia, remnants original Afromontane forest vegetation are largely restricted to church yards and other sacred groves in a matrix cropland semiarid degraded savanna. To assess potential for natural regeneration, species composition diversity all fragments (10) study area 13,000 ha were analyzed relation environmental soil variables. Using random design density approximately one plot per 2 ha fragments, 31 20×20 m plots sampled. Indicator analysis MRPP tests yielded five communities representing two types savanna habitat. The had species-poor tree shrub community which rather homogeneous most abundant. NMDS variance indicated that topographical gradient correlated phosphorus, depth, stoniness proximity river system explained major differences separated moist dry communities. grazing intensity further partitioned habitats. Present their correlates indicate secondary climax probably consisted interlaced by broad strips along rivers streams not continuous, mono-dominant Juniperus as is often presumed. Negative effects on increased with decreasing patch increasing shape irregularity. Nevertheless, remaining important role landscape ecology region refuges pools should be protected managed accordingly. If seed dispersal from into exclosures subsequent recruitment both successful, type likely establish woodland, if properly, eventually may arise. Increasing size small patches placing plantations vicinity expected yield immediate results. This approach increase likelihood colonisation frugivorous birds thus foster regeneration native woody species.