Worldwide study shows biodiversity is critical in improving crop production
Posted on: 16 October 2019
Over the past two decades, approximately 20% of the Earth’s cultivated surfaces have become less productive. According to the latest report from the United Nations’ Food and Agriculture Organization (FAO), humans are the culprit – we have not done enough to protect nature’s biodiversity.
Today an international research team coordinated by the University of Würzburg and Eurac Research, and involving experts from Trinity College Dublin and UCD, confirmed the advantages of biodiversification: agricultural fields with greater biodiversity are better protected from harmful insects, promote pollination, and produce higher yields. The team has just published its findings in leading international journal, Science Advances.
Ecologists and biologists compared data from around 1,500 agricultural fields dotted across the globe: from corn fields in the American plains to oilseed rape fields in southern Sweden, and from coffee plantations in India and mango plantations in South Africa to cereal crops in the Alps.
They analysed two ecosystem services (processes regulated by nature that are beneficial and free for humans): (1) the pollination service provided by wild insects and (2) biological pest control service, which is the ability of an environment to use predators naturally present in the ecosystem to defend itself from harmful insects.
In landscapes where the variation of crops, hedges, trees and meadows is greater, wild pollinators and “beneficial insects” are more abundant and diverse. Not only do pollination and biological control increase, but so does the crop yield.
On the other hand, monocultures (landscapes featuring single crop species) are the cause of roughly a third of the negative effects on pollination that result from landscape simplification (measured by loss of ‘pollinator richness’). This effect is even more pronounced when considering the biological control of harmful insects – losing natural predator diversity amounts to 50% of the total consequences of landscape simplification.
As a result of these findings, the researchers recommend that healthy environments be maintained through biodiversity and by diversifying crops and landscapes as much as possible.
Jane Stout, Professor in Botany in Trinity’s School of Natural Sciences, is a co-author of the study.
She said: We contributed data on oil-seed rape pollination in Ireland to add to this global analysis. Although oil-seed rape has traditionally not been managed to maximise pollinators here in Ireland, our work showed a 30% yield decrease when pollinators were not present. Given that Irish bees are in decline in the Irish countryside, this could limit overall productivity.
This new study shows that in order to bring back biodiversity on farmland, and to ensure maximum current and future yields, we must maintain and increase diversity in our farmed landscapes, both here in Ireland, and worldwide.
Dara Stanley, an assistant professor at UCD and co-author of the study, added: “This study shows that biodiversity on farmland can actually benefit agricultural production. This is important in the context of the development of the new CAP in Europe, as it provides more evidence that biodiversity needs to be a key part of sustainable agricultural production going forwards.”
Matteo Dainese, a biologist at Eurac Research and first author of the study, said: “Our study shows that biodiversity is essential to ensure the provision of ecosystem services and to maintain a high and stable agricultural production. For example, a farmer can depend less on pesticides to get rid of harmful insects if natural biological controls are increased through higher agricultural biodiversity.”
Ingolf Steffan-Dewenter, an animal ecologist from the Department of Animal Ecology and Tropical Biology at the University of Würzburg, was the initiator of the study within the EU project ‘Liberation’.
He said: “Under future conditions with ongoing global change and more frequent extreme climate events, the value of farmland biodiversity ensuring resilience against environmental disturbances will become even more important. Our study provides strong empirical support for the potential benefits of new pathways to sustainable agriculture that aim to reconcile the protection of biodiversity and the production of food for increasing human populations.”
Funding for the study came from the collaborative projects EU-FP7 LIBERATION and Biodiversa-FACCE ECODEAL.