2021 Volume 103 Issue 4 Pages 253-258
Since the dead branches and leaves of Japanese cedar, Cryptomeria japonica, are kept attached on trees, these substrata are likely to be decomposed by microorganisms such as bacteria and fungi before they fall onto the forest floor. However, some microorganisms are eaten by nematodes, and thus nematode communities can indirectly be involved in the decomposition process of above substrata. In this study, we aimed to clarify the nematode community inhabiting at the above-ground part of cedar forests. We established five plots within a 1 ha cedar stand in Mie Prefecture. In the plots, three mature trees were arbitrarily selected, and fresh leaves, dead leaves, barks, and forest floor litters were collected. Nematodes were collected from each organ by the Baermann funnel method and observed under a light microscope. We identified nematodes into taxa at the order, family or genus level, and they were also categorized into one of 5 feeding groups based on their oral parts. Moreover, mycelial length was estimated directly observing hyphae in each organ under the microscope. Fungivorous nematodes were predominated accounting for more than 70％ in each organ. Furthermore, the nematode feeding groups of fresh and dead leaves were significantly nested with those derived from barks and forest floor litter. Mycelial lengths were significantly greater at dead leaves and forest floor litters than fresh leaves. These results indicated that nematodes inhabit the aboveground parts of cedar forests, and fungal distribution can affect the maintenance and assemblage pattern of nematodes.
