Composition and Structure of the Nematode Communities in Nitisols, Acrisols, and Suspended Soils of Bale National Park (Southeastern Ethiopia)

Nematode complexes of the forest soils of Bale National Park in Ethiopia (southern macroslope) have been investigated at the end of wet season. The nematodes of Nitisols and Acrisols formed in Hagenia and Hagenia-Juniperus forests, and suspended soils formed in Hagenia abyssinica canopy have been compared. The nematodes were extracted by the Baermann technique with subsequent determination of total numbers, taxonomic diversity, and trophic groups. The status of ecosystems was determined using ecological indices. The number of nematodes in suspended soils was several times higher than in forest soils, with the biomass of animals ten times greater. The bacterivorous nematodes prevailed in all soils; in the suspended soil their percentage was 75%. The plant parasites and fungivorous nematodes were few in suspended soil compared to Acrisols and Nitisols. In the suspended soils that were less diverse and structural, the fast-reproducing genera-colonizers prevailed. Acrobeloides, Plectus and Rhabditis were eudominants in the suspended soils, whereas Panagrolaimus, Helicotylenchus, and Mesodorylaimus predominated in Nitisols. The trophic webs of all three soil types were mature, stable, with low level of disturbance.