Fruit quantity and quality of strawberries benefit from enhanced pollinator abundance at hedgerows in agricultural landscapes

Animal pollinators are in a serious decline due to habitat loss, isolation and landscape fragmentation, putting pollination services to crops at risk. Hedgerows have been repeatedly emphasized as landscape elements that provide nesting and food resources, connect fragmented habitats and could thus facilitate crop pollination. However, the beneficial and potentially also detrimental impacts of hedgerows on crop pollination remain poorly studied. Here, we analysed the effects of pollinators and herbivorous pollen beetles (Meligethes spp.) on quantity and quality of strawberries from phytometer plants located at forest-connected hedgerows, isolated hedgerows and on grassy margins without any hedgerows. Higher pollinator abundance increased strawberry weight, whereas pollen beetle abundance reduced strawberry weight. Strawberry weight was significantly reduced by 29% at isolated hedgerows and 32% on grassy margins, compared to berries at connected hedgerows. Plants placed at forest-connected hedgerows produced more high quality strawberries with 90% classified as “marketable” whereas only 75% of strawberries from plants at isolated hedgerows, 48% of strawberries from plants on grassy margins and 41% of strawberries from self-pollinated control plants where classified as marketable. Consequently, increased habitat connectivity through hedgerows enhanced the commercial value of strawberries from 9.27 € per 1000 strawberries for plants grown on grassy margins to 14.95 € for plants located at forest-connected hedgerows. Correspondingly, pollinator abundance was highest on phytometer plants at forest-connected hedgerows, lowest on grassy margins and intermediate at isolated hedgerows. Pollen beetle abundance on phytometer plants was not affected by hedgerows. Our study highlights the importance of hedgerows and habitat connectivity for promoting pollination services in agricultural landscapes, with economically important benefits for crop quantity and quality.