Madagascar, the world's largest producer of vanilla, provides an important basis for the production of vanilla, a popular ingredient in ice cream, cakes and cookies. The vanilla orchid is grown in the tropical northeast of the island. For the past five years, a research team from the University of Göttingen and the University of Antananarivo has been studying vanilla cultivation and its impact on humans and nature. Researchers found that growing vanilla in agroforestry systems, where vanilla grows under shady trees, has benefits for both humans and nature over other land uses. However, this only applies when vanilla is grown on fallow land that has already been deforested. The results were published in the Proceedings of the National Academy of Sciences (PNAS).
The research team collected data on biodiversity, ecosystem services such as carbon storage, and harvest and profitability considering different land uses. Scientists focused on vanilla agroforestry systems, which are often set up directly in the forest: farmers remove shrubs and individual trees and plant the vanilla orchid directly under the remaining trees. Alternatively, vanilla agroforestry systems can be built on wasteland previously burned for paddy fields. In this case, the land is more open to vanilla cultivation, allowing trees to grow back.
The team took past land use into account in their analysis. Species richness data from seven species groups, five ecosystem services, and harvest and profitability were compared to historical land use. This interdisciplinary approach allowed researchers to study the positive and negative impacts of land-use change, while considering multiple perspectives to get a comprehensive picture.
Vanilla agroforestry established on open fallow land offers distinct benefits for people and nature. The conversion of forests to vanilla agroforestry systems, on the other hand, leads to disadvantages for animals and plants as important forest functions are lost. Converting more forests to vanilla agroforestry systems can therefore only be justified as an alternative to burning land, where both biodiversity and ecosystem services suffer even more.
dr Fanilo Andrianisaina, researcher at the University of Antananarivo, Madagascar, emphasizes the benefits of vanilla cultivation for the farmers: "With the high prices that we were able to document during the study period, vanilla is very profitable
. Of course, a lot of money also gets stuck with middlemen and exporters, but many vanilla farmers have been able to afford new houses, solar systems or motorbikes; that would have been unthinkable before." However, the team also observed that vanilla prices have plummeted over the past two years, threatening profits.
This raises the question to what extent the research results can be transferred to the future and other landscapes. "For me, a fair and stable vanilla price is extremely important in the long term," says Dr. Dominic Martin from the University of Göttingen, first author of the study. "The constant ups and downs in prices make it impossible for producers to focus on sustainable vanilla cultivation - the risk of being economically dependent on vanilla alone is just too high," he adds.
Professor Holger Kreft from the University of Göttingen, who coordinated the study, says that "previous land use is also crucial when assessing land use change in other regions of the world. This means that our model is universally applicable and the relevance of our results for agriculture and ecology around the world."