Abstract
Uncultivated field margins are important refugia for pollinating insects in agricultural landscapes. However, the spill-over of pollination services from field margins to adjacent crops is poorly understood. This study (i) examined the effects of landscape heterogeneity on pollinator occurrence in permanent field margins and pollinator visitation to adjacent mass-flowering turnip rape (Brassica rapa ssp. oleifera) in boreal agricultural landscapes, and (ii) tested whether pollinator abundance and species richness in field margins predict abundance and species richness of crop visitors. Pollinators visiting the crop were more affected by landscape heterogeneity than pollinators in adjacent margins. Species richness, total abundance, and the abundance of syrphid flies visiting the crop increased with increasing landscape heterogeneity, whereas, in field margins, landscape heterogeneity had little effect on pollinators. In field-dominated homogeneous landscapes, wild pollinators rarely visited the crop even if they occurred in adjacent margins, whereas in heterogeneous landscapes, differences between the two habitats were smaller. Total pollinator abundance and species richness in field margins were poor predictors of pollinator visitation to adjacent crop. However, high abundances of honeybees and bumblebees in margins were related to high numbers of crop visitors from these taxa. Our results suggest that, while uncultivated field margins help pollinators persist in boreal agricultural landscapes, they do not always result in enhanced pollinator visitation to the adjacent crop. More studies quantifying pollination service delivery from semi-natural habitats to crops in different landscape settings will help develop management approaches to support crop pollination.
Highlights
Agricultural intensification has led to pollinator decline that poses a serious threat to food production, ecosystem stability and human well-being (Potts et al 2016)
Pollinator occurrence is strongly driven by local availability of flower resources (Lagerlöf et al 1992; Bäckman & Tiainen 2002), which is more variable than on a mass-flowering crop field
Most pollinator species were probably able to spread into rewarding field margins regardless of the landscape heterogeneity, due to generally high landscape heterogeneity of our study region, and high connectivity of field margins to other uncultivated habitats
Summary
Agricultural intensification has led to pollinator decline that poses a serious threat to food production, ecosystem stability and human well-being (Potts et al 2016). To mitigate the negative trends, researchers have suggested diversifying farming systems (Kremen & Miles 2012) and adopting ecological intensification (Kovács-Hostyánszki et al 2017). Both strategies include retaining, creating and managing semi-natural habitats such as flower strips (Haaland et al 2011), hedgerows (M'Gonigle et al 2015) and fallows (Toivonen et al 2015) around crop fields. Several studies have assessed how crop pollination services decline with distance from semi-natural habitats (Ricketts et al 2008; Carvalheiro et al 2010; Bailey et al 2014; Woodcock et al 2016). Fewer studies have measured both pollinator occurrence in semi-
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
