Pollinators are a highly diverse group, mainly including bees and bumblebees, but also hoverflies and butterflies. They are essential for the reproduction of wild plants and crops. Photo: Blanca Arroyo

A new international study has found that the European Union’s targets to prevent the disappearance of pollinators are not enough to halt the decline of these insects, which are vital not only for sustaining biodiversity but also for supporting agricultural production. The research, published in Science and involving Spain’s Doñana Biological Station (EBD-CSIC) and the Institute for Sustainable Agriculture (IAS-CSIC), calls for an expansion of natural habitats within farmland, alongside measures to ensure their quality and long-term stability.

The EU Biodiversity Strategy states that, in order to provide space for wildlife, pollinators and natural pest regulators, at least 10% of agricultural area should be transformed into high diversity landscape features by 2030. These include buffer strips, rotational or non-rotational fallow land, hedgerows, non-productive trees, terraces and small ponds.

But the researchers argue that this 10% commitment is not enough to secure the survival of pollinators. To reach these conclusions, the research team examined how the area and quality of natural habitats influence populations of different pollinators. Based on 59 studies in 19 countries, the study shows that solitary bees require 16% of natural habitat in farmland areas, bumblebees 18%, and butterflies 37% for effective protection. However, the EU Biodiversity Strategy currently sets a target of 10%, which is insufficient to ensure their survival.

The study confirms a simple rule: the more natural habitat, the more pollinators in farmland areas. Results also revealed that habitats Habitats with more flowering plants also harbored more pollinators of all groups than areas with few flowers. However, habitat quality does not always compensate for a lack of available space. “We have seen that even if these areas are of high quality, it is impossible to maintain healthy pollinator populations if the minimum natural habitat is not reached,” explains Ignasi Bartomeus, a CSIC researcher at the Doñana Biological Station.

In this regard, the research team emphasizes that the key is to first expand the extent of natural habitats. “It is better to focus on increasing the area of natural habitats first, instead of on managing small habitats, even when they have many flowers,” says Gabriella Bishop, the study’s first author and a researcher at Wageningen University.

Quality and permanence of natural habitats

The study also warns that simply increasing the extent of natural habitats will not be enough unless the quality and long-term stability of these areas are ensured. Pollinator conservation efforts in Europe have so far relied heavily on temporary measures in small pockets of farmland, such as creating wildflower strips alongside crops. Previous research has shown that such actions can boost insect and pollinator numbers in the short term, but they do not provide a lasting solution.

“There are crops, such as many fruit trees, where maintaining biodiversity is compatible with high agricultural production, but in more intensive crops, such as sunflower, economic compensation is needed to allocate farmland for biodiversity conservation,” explains Ignasi Bartomeus.

That is why the research team stresses the need for stable support mechanisms for the farming sector. José Luis González Andújar, from the Institute for Sustainable Agriculture (IAS-CSIC) and a co-author of the paper, said: “For real change to take place, farmers must be financially recognised for dedicating part of their land to creating and maintaining natural spaces. This effort needs to be sustained for at least two decades; otherwise, the lack of stability would create uncertainty in the farming sector, and pollinators would gain little benefit.”

 “Transitioning to more sustainable agriculture requires thinking about the landscapes we want, which involves considering the ecological, economic, and social aspects of the landscape,” concludes researcher Ignasi Bartomeus.

This research is part of the European SHOWCASE project, funded by the EU Horizon 2020 program, which seeks to create synergies for integrating biodiversity conservation into agricultural practices.

Reference

Gabriella A. Bishop, David Kleijn, Matthias Albrecht, Ignasi Bartomeus et al. Critical habitat thresholds for effective pollinator conservation in agricultural landscapes. Science. DOI: 10.1126/science.adr214