Dominance of honey bees is negatively associated with wild bee diversity
in commercial apple orchards regardless of management practices Short
title : Honey bees affect wild bees in apple orchards
Abstract
Commercial apple production relies on managed honey bees for
pollination, and on intensive management for pest control. Previous
studies revealed the detrimental effects of these factors on wild bee
diversity in agroecosystems, and the pollination services they provide.
However, the extent to which honey bee dominance and management interact
under field-realistic conditions to shape wild communities has never
been investigated. We measured the species richness and functional and
phylogenetic diversity of wild bees associated with apple blossoms, in
46 organic and non-organic orchards, and along a climatic gradient
across Western Europe and Morocco. Our results consistently show a
strong and negative association between honey bee dominance and all
diversity indices, regardless of local practices and surrounding
landscape cover. Collectively, we show that wild bee diversity decreases
with increasing honey bee density, with alternative management practices
(i.e., organic) having no significant influence on wild bee communities
in commercial apple orchards.