Vanilla is often belittled as bland, but surveys now show that demand for this flavouring can have grave results: some vanilla farms endanger plant biodiversity. The good news is that old-fashioned forest-covered vanilla plantations could be less of a threat than industrial-style modern cultivation.

About 80% of the world’s vanilla, which is made from seed pods of the bourbon vanilla orchid (Vanilla planifolia), is produced in Madagascar. Sam Cotton at the Bristol Zoological Society, UK, and his colleagues tallied the number and types of plants in natural forests in northeast Madagascar, where most of the island’s vanilla is cultivated, and on various types of vanilla plantations.

There were about 70% fewer plant species in intensively managed plantations — where the original vegetation has been removed or altered — than in natural forests. Traditional farms, which retain some native vegetation, also exhibited lower biodiversity than natural forests. But traditional farms next to wild forest land had a much lower degree of species loss than intensive plantations, suggesting that old-fashioned vanilla cultivation could be more sustainable than intensive farming.