Original ArticlesInfluence of oil palm monoculture on the taxonomic and functional composition of aquatic insect communities in eastern Brazilian Amazonia

Large scale palm oil plantations for the production of vegetable oil are among the most harmful agricultural activities to biodiversity, especially given their rapid expansion, worldwide. Many cases of species loss have already been recorded in Asian countries, although research is still incipient in the Amazon basin, and the environmental impacts of these monocultures on freshwater ecosystems in the Neotropical region are still poorly understood. The present study evaluated the effects of oil palm plantations on the physical structure of stream habitats and the resulting changes in the taxonomic and functional composition of aquatic insect communities. A total of 2100 specimens of the orders Ephemeroptera, Plecoptera and Trichoptera were collected during the present study, representing 40 genera and 16 families. The hypothesis tested was that the taxonomic and functional diversity of the orders Ephemeroptera, Plecoptera and Trichoptera (Insecta) decreases in streams surrounded by oil palm plantations in comparison with those embedded in forested areas. In the plantation streams, the taxonomic richness and composition, and the functional richness are modified significantly. Functional composition appeared unaltered despite reduced canopy cover associated with oil palm streams. These effects emphasize the importance of the riparian vegetation for the protection of the aquatic communities found in oil palm plantations. The maintenance of the riparian vegetation may mitigate the impacts of plantations, contributing to the conservation of insect communities and associated biodiversity.