LITTERFALL, LEAF LITTER DECOMPOSITION AND LITTER INVERTEBRATES IN PRIMARY AND SELECTIVELY LOGGED DIPTEROCARP FOREST IN SABAH, MALAYSIA

A two-year study on leaf litter decomposition and litter invertebrates was carried out in a primary (4 ha (= 4 x 10(4) m2) and logged dipterocarp forest plot (2.5 ha) in the Danum Valley, Sabah, Malaysia. Annual leaf litterfall, leaf litter layer mass and leaf litter decomposition, measured as leaf litter mass loss, were not significantly different between plots. Spatial variation among the 30 replicate sites within each plot was high. Annual rates of total litterfall, leaf litterfall and leaf litter mass loss were 11.5, 6.6 and 6.4 t ha-1 for the primary forest plot and 11.9, 6.2 and 5.5 t ha-1 for the logged forest plot. Rainfall (3000 mm y-1) and litterfall were high throughout the year and rates of litterfall and litter disappearance were not related to the pattern of rainfall. In the primary and logged forest, leaf litter layer mass and annual rates of leaf litter disappearance increased with annual leaf litterfall. In the primary forest, the abundance of litter invertebrates increased with mass of leaf litter and fine roots. This invertebrate abundance was higher in the primary forest with a significantly higher abundance of mites, pseudoscorpions and termites. The proportion of mites and pseudoscorpions of the invertebrate fauna was higher in the primary forest; beetles, millipedes and cockcroaches were higher in the logged forest. The most abundant invertebrates were ants, springtails, spiders, woodlice and mites.