Abstract The preservation of pollinator habitat on croplands in the form of hedgerows, wildflower strips, and natural and semi-natural areas can help maintain and enhance wild bee populations in agricultural landscapes. However, there have been few comparisons of the effectiveness of different types of field-margin pollinator habitat in maintaining bee diversity and pollination of the focal crops. We compared wild bee abundance, species richness and community composition between strawberry crops bordered by hedgerows, and those bordered by larger expanses of natural land (forests). Strawberry is an ideal crop in which to investigate pollinator export from field margins as the rows are covered with straw, which reduces habitat for ground-nesting bees within the crop; thus, most wild pollinators need to enter the crop from the margins. We sampled bees in six strawberry fields with hedgerow margins and six strawberry fields with forested margins of at least 200 m in length, using a paired design. We examined strawberry pollen deposition at regular intervals into the fields, and the magnitude of pollinator export from the field margins towards the centre of the crops. We found that bees as a group were no more species-rich or abundant in crops bordered by forests than in crops bordered by hedgerows, although large-bodied bees were more abundant in the former than the latter. Regardless of field-margin type, we found that small wild bee abundance declined significantly from the edge to the centre of the crop, but honey bee (Apis mellifera L.) and large-bodied bee abundance did not. Strawberry pollen deposition also did not decline with distance into the crop. Although previous work indicates that small wild bees are more effective (yield-increasing) pollinators of strawberry on a per-visit basis, their limited foraging ranges suggest they may only pollinate areas near the crop margins, given typical field sizes in our area.

中文翻译：

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无论田地边缘栖息地如何，小野蜂丰度都会随着进入草莓作物的距离而下降

摘要 以树篱、野花带、自然和半自然区域的形式保护农田上的传粉媒介栖息地有助于维持和增加农业景观中的野生蜜蜂种群。然而，关于不同类型的田边传粉媒介栖息地在维持蜜蜂多样性和重点作物授粉方面的有效性的比较很少。我们比较了以树篱为界的草莓作物与以大片自然土地（森林）为界的草莓作物之间的野生蜜蜂丰度、物种丰富度和群落组成。草莓是一种理想的作物，用于调查田边传粉媒介的输出，因为这些行被稻草覆盖，这减少了作物中地面筑巢蜜蜂的栖息地；因此，大多数野生传粉者需要从边缘进入作物。我们使用配对设计在六个具有树篱边缘的草莓地和六个具有至少 200 m 长的森林边缘的草莓地中对蜜蜂进行采样。我们定期检查了草莓花粉在田间的沉积，以及从田地边缘向作物中心输出的传粉媒介的数量。我们发现，作为一个群体，蜜蜂作为一个群体在森林边界的作物中并不比在树篱边界的作物中物种丰富或丰富，尽管前者比后者中体型更大的蜜蜂更丰富。无论田地边缘类型如何，我们发现小野蜂丰度从作物边缘到中心显着下降，但蜜蜂（Apis mellifera L.）和大型蜜蜂丰度没有。草莓花粉沉积也没有随着进入作物的距离而减少。