The main objective of my study is to quantify species richness, functional composition and host-parasitoid interactions of pollinating bees and predatory wasps in different land-use systems in Sumatra, Indonesia. This will be achieved by using standardized nesting resources for pollinating bees and predatory wasps, also called "trap-nests" (following Tscharntke et al.1998, Veddeler et al. 2010). Different landscapes will be compared on this basis: lowland rainforest, rubber monoculture plantation and oil palm monoculture plantation in riparian vs. non riparian sites. The hypothesis is that functional diversity of insects suffers more from habitat transformation that taxonomic diversity, and less in riparian than non-riparian sites.
As a second part of my study, pollen samples will also be collected, analyzed and identified from cavity-nesting bees in the different landscapes, as a tool to construct pollen networks. These data will be analyzed in a broader context in association with project A01, in which pollen collected from birds, bats and insects will be studied. The objective is to evaluate the consequences of landscape transformation for the functioning of plant-animal interactions and the patterns of pollinator community composition. This income is important to achieve the objective of biodiversity and ecosystem services conservation in the land-use systems, as pollination is a major service for the maintenance of plant diversity and crop production.
Richness, functional composition and host-parasitoid relationships of bees and wasps, as well as pollen networks will also be investigated in the framework of an enrichment planting experiment, in which oil palm plantations are enriched with native tree species within plantation gaps. Another point concerns variation in local management of oil palm plantations, which will be compared from the point of view of the consequences for pollinating bees and predatory wasps.