From marginal croplands to natural habitats: A methodological framework for assessing the restoration potential to enhance wild-bee pollination in agricultural landscapes

Intensive agriculture increases crop yields, but harms biodiversity and associated ecosystem services such as pollination. To sustain wild-bee pollination in intensive agricultural landscapes, a minimum of (semi-) natural habitat is needed in the vicinity of crop fields. However, restoration of (semi-) natural habitat is a challenge, especially when most land is allocated to commodity production.

To evaluate the restoration potential of marginal lands to enhance pollination in intensive agricultural landscapes.

We simulated restoration scenarios in marginal agricultural lands (abandoned and degraded fields, and field edges) in La Vallée-du-Richelieu (Quebec, Canada), aimed at enhancing pollination provision and increasing (semi-) natural habitat coverage by at least 20% within 1 km from crop fields, the estimated minimum amount required to sustain wild-bee populations. We then evaluated the extent to which restoration targets were reached in our scenarios.

More than half of the agricultural region studied remained with less than 20% (semi-) natural area coverage, and wild-bee pollination provision could not be ensured across the whole agricultural region after restoration. However, our results show that there is still an important potential for increasing natural habitat coverage by restoring marginal agricultural lands alone.

Restoration of marginal lands has a key role to play in the transition towards multifunctionality of production landscapes but might not be sufficient to achieve goals such as those adopted at the COP15 (e.g., restoring 30% of degraded land). Our framework can assist landscape planners in evaluating the restoration potential of agricultural landscapes, as well as its limitations.