Organic farming positively affects honeybee colonies in a flower‐poor period in agricultural landscapes

Abstract

1. Conventional farming has been implicated in global biodiversity and pollinator declines and organic farming is often regarded as a more ecological alternative.However, the effects of organic farming on honeybees remain elusive, despite honeybees' importance as pollinators of crops and wild plants.2. Using 6 years of data from a large-scale study with fortnightly measurements of honeybee colony performance traits (10 apiaries per year distributed across a 435 km 2 -large research site in France), we related worker brood area, number of adult bees and honey reserves to the proportions of organic farmland in the surroundings of the hives at two spatial scales (300 m and 1,500 m).3. We found evidence that, at the local scale, organic farming increased both worker brood production and number of adult bees in the period of flower scarcity between the blooms of oilseed rape and sunflower (hereafter 'dearth period'). At the landscape scale, organic farming increased honey reserves during the dearth period and at the beginning of the sunflower bloom.4. The results suggest that worker brood development benefitted from organic farming mostly through a more diverse diet due to an increase in the availability of diverse pollen sources in close proximity of their hives. Reduced pesticide drift may have additionally improved bee survival. Honey reserves were possibly mostly affected by increased availability of melliferous flowers in foraging distance. Synthesis and applications.Organic farming increases honeybee colony performance in a period of resource scarcity, likely through a continuous supply of floral resources including weeds, cover crops and semi-natural elements. We demonstrate how worker brood area increases in the critical dearth period (between the blooms of oilseed rape and sunflower). This has previously been linked to winter colony survival, suggesting that organic farmland may mitigate repercussions of intensive farming on colony vitality. We conclude that organic farming benefits a crucial crop pollinator with potential positive implications for agriculture in the wider landscape. K E Y W O R D S agricultural intensification, floral resources, honey production, honeybee, organic farming, rapeseed, spatial scale, worker brood | 1961 Journal of Applied Ecology WINTERMANTEL ET AL. S U PP O RTI N G I N FO R M ATI O N Additional supporting information may be found online in the Supporting Information section at the end of the article. How to cite this article: Wintermantel D, Odoux J-F, Chadoeuf J, Bretagnolle V. Organic farming positively affects honeybee colonies in a flower-poor period in agricultural landscapes. J

Transformation of agricultural landscapes in the Anthropocene: Nature's contributions to people, agriculture and food security

“…Organic agriculture has the potential to mitigate adverse effects of intensive farming. Species richness, functional diversity and abundance of a wide-range of taxa are often higher on organic than conventional farms ( but see Brittain et al, 2010;Gallé et al, 2019;Gomiero et al, 2011;Hole et al, 2005;Holzschuh et al, 2008;Katayama et al, 2019;Krauss et al, 2011;Schneider et al, 2014;Wintermantel et al, 2019). Positive effects of organic agriculture on biodiversity vary among landscape and crop types, levels of crop diversification.…”

A global assessment of drivers and risks associated with pollinator decline

“…Observed trends in wild pollinators have been mostly linked with changes in land management 12 , climate change 13 , and agrochemical use 14 , although these analyses are largely restricted to Europe and North America. Restoring or diversifying habitats and reducing management pressures such as pesticides and grazing have been shown to positively affect wild pollinator populations and managed honeybee health [15][16][17] .…”

Summer weather conditions influence winter survival of honey bees (Apis mellifera) in the northeastern United States

“…Previous studies have evaluated how colony growth, honey production and survival correlates with particular land use practices, such as the percentage of agricultural land or the percentage of certain crops in the area surrounding the hive 16 – 19 . However, while several studies have indicated that honey bees show reduced growth or higher mortality with increasing urban or agricultural land use 16 , 17 , 20 , others have found that agricultural land use is positively correlated with colony survival 18 .…”