Diversity and trophic positions of beetle (Coleoptera) families after rainforest conversion to monoculture cash crops in Jambi, Sumatra
Deforestation by increasing agricultural land is the most direct threat in Southeast Asia tropical rainforests, especially the rise of oil palm (Elaeis guineensis) and rubber (Hevea brasiliensis) plantation areas. Lowland rainforests of Jambi province, Sumatra, is strongly impacted by land-use change since 1990, and with it, its high diversity of canopy arthropods. Among arthropods, beetles (Coleoptera) is one of the most group-rich in rainforest canopy, which includes currently 180 families with diverse feeding strategies (herbivores, predators, fungivores, scavengers, etc), and occupying key positions in food chain as well as maintaining ecological functions. I assess the influence of four land-use systems on canopy beetle diversity and trophic ecology. My study investigates, on a first hand, the diversity of beetle family community (by Hill numbers) from rainforest conversion, via jungle rubber, to oil palm and rubber plantations, and on another hand, the trophic position and trophic niche space of beetle community using 15N and 13C stable isotopes across the same land-use gradient. I expect a decline in beetle diversity, and higher trophic position with narrower trophic range of beetle community in both monocultures, showing the negative effects of single-tree plantations on beetles. My study will come to complete previous studies demonstrating the loss of animal communities from rainforest transformation to monoculture cash crops, and help to understand the processes affecting biodiversity in order to apply effective solutions in agricultural areas.