Promoting vanilla cultivation on fallow land

Preserving biodiversity while securing the economic livelihood of smallholder farmers growing vanilla in Madagascar is possible, according to a study by the Universities of Göttingen, Marburg and Hohenheim (Germany) which was published in July 2022. Farmers do not have to clear land to achieve high yields, they say. Vanilla plantations established on fallow land do not differ in terms of yield from those established in the forest. Cultivation on fallow land also increases biodiversity there. Vanilla cultivated in the forest instead of on fallow land led to a loss of 23 per cent of all species, and endemic species decreased by 47 per cent.

The researchers recorded crop yields in vanilla agroforestry systems in northeastern Madagascar, the world's largest vanilla-growing area, which is dominated by smallholder farmers. They related these results to the biodiversity as identified by trees, herbaceous plants, birds, amphibians, reptiles, butterflies and ants. The economic and ecological aspects of cultivation were combined. The main finding was that increasing vanilla yields were unrelated to overall biodiversity. In addition, the vanilla harvest on plantations established on fallow land did not differ from the harvest of plantations established in the forest.

If the farmers planted the vanilla more densely or increased the length of the vanilla plants, the harvest was higher, but the number of tree and reptile species decreased. However, this had no negative impact on birds, amphibians, butterflies, ants and herbaceous plants. Species diversity can be increased by high tree cover on plantations and in the landscape. 

"Promoting vanilla cultivation on fallow land is ecologically and economically significant. This contributes to the current UN Decade for Ecosystem Restoration. In addition, this study illustrates possibilities for promoting and conserving biodiversity outside protected areas," says co-author Professor Ingo Grass, ecologist for tropical agricultural systems at the University of Hohenheim.

(University of Göttingen/ile)

Read more on the website of the University of Göttingen

Original publication: Annemarie Wurz et al. Win-win opportunities combining high yields with high multi-taxa biodiversity in tropical agroforestry. Nature Communications 2022.