Removing non-crop flowers within orchards promotes the decline of pollinators, not their conservation: a comment on McDougall et al. (2021)

Abstract

Reducing the exposure of pollinators to pesticides is an important issue aimed at preserving biodiversity and ecosystem functioning in agroecosystems (Gill et al. 2012, Goulson et al. 16 2015). In order to prevent this and other related issues, the main principles for improving the sustainability of agriculture include fostering the development of existing natural processes as well as the internal cycling of nutrients and energy; for example, by reducing the use of herbicides and insecticides, increasing the biodiversity within crop fields, and avoiding bare soil with permanent vegetation cover (Horrigan et al. 2002, Brodt et al. 2011, Kremen et al. 2012, Garibaldi et al. 2017, Kleijn et al. 2019). In a recent paper by McDougall et al. (2021) published in the journal 'Pest Management Science” entitled 'Managing orchard groundcover to reduce pollinator foraging post-bloom”, the authors propose removing flowering ground herbs once the mass flowering period of the crop ends as a bee conservation strategy. With a multiyear field-experimental approach, they conclude this practice reduces the abundance and diversity of pollinators within the crop during the post-bloom stage, thus reducing their exposure to pesticides (this reduced pesticide exposure is expected, but was not quantified). Here, we give three main arguments against the proposal of McDougall et al. (2021); we instead advocate for providing feeding resources to farm associated pollinators and other beneficial fauna through the promotion of flowering herb cover within crop fields (Requier et al. 2015), as well as reducing herbicide and pesticide use (EC 2022, Goulson et al. 2015).