Tropentag 2011 brings together prominent researchers and thinkers alike to discuss and exchange the challenges of development on the margin. Food security, rural incomes and livelihood diversification are in the core of the debate, while the conservation of biodiversity and the valuation of ecosystem services attract more and more attention. With a special invited paper on Resource use and ecosystem services by Christian Borgemeister from ICIPE, this session highlighted that the conservation of biodiversity does not have to exclude economic opportunities, but at the same time its success is vulnerable to various risks. Christian Borgemeister, ICIPE