Crop failures have pushed up food prices globally (Nature 472, 169; 2011). Human well-being depends on biodiversity and natural habitats as a source of food. Ironically, the countries harbouring these vital natural assets are also those currently facing the most severe food crises.

A report from the investment bank Nomura (http://go.nature.com/pwrlc9) introduces a global index for measuring nations' food vulnerability. The most vulnerable depend totally on imported food, and citizens spend more than one-third of their salaries on it.

Of the 35 most vulnerable countries, 15 contain tropical biodiversity hotspots. To produce more food, these countries may lease out their biodiversity-rich land to farm cash crops. Liberia, for example, intends to add 220,000 hectares of oil-palm plantation (http://go.nature.com/xblcjz) to its existing 1.6 million hectares of agricultural land in the southeast, one of the last strongholds of tropical forest in western Africa.

Vulnerable nations need better cooperation among governments to address the structural causes of imbalances in the international agricultural system; more research into new technologies that incorporate the food-production requirements of the rural poor; and stronger protection of natural systems by linking biodiversity preservation to increased food security.