The diversity of beetle assemblages in different habitat types in Sabah, Malaysia

The diversity of beetle assemblages in different habitat types (primary for est, logged forest, acacia plantation and oil palm plantation) in Sabah, Ma laysia was investigated using three different methods based on habitat leve ls (Winkler sampling, flight-interception-trapping and mist-blowing). The o verall diversity was extremely high, with 1711 species recorded from only 8 028 individuals and 81 families (115 family and subfamily groups). Differen t degrees of environmental changes had varying effects on the beetle specie s richness and abundance, with oil palm plantation assemblage being most se verely affected, followed by acacia plantation and then logged forest. A fe w species became numerically dominant in the oil palm plantation. In terms of beetle species composition, the acacia fauna showed much similarity with the logged forest fauna, and the oil palm fauna was very different from th e rest. The effects of environmental variables (number of plant species, sa pling and tree densities, amount of leaf litter, ground cover, canopy cover , soil pH and compaction) on the beetle assemblage were also investigated. Leaf litter correlated with species richness, abundance and composition of subterranean beetles. Plant species richness, tree and sapling densities co rrelated with species richness, abundance and composition of understorey be etles while ground cover correlated only with the species richness and abun dance of these beetles. Canopy cover correlated only with arboreal beetles. In trophic structure, predators represented more than 40% of the species a nd individuals. Environmental changes affected the trophic structure with p roportionally more herbivores (abundance) but fewer predators (species rich ness and abundance) in the oil palm plantation. Biodiversity, conservation and practical aspects of pest management were also highlighted in this stud y.