Data from: Complementary crops and landscape features sustain wild bee communities

Wild bees, which are important for commercial pollination, depend on floral and nesting resources both at farms and in the surrounding landscape. Mass-flowering crops are only in bloom for a few weeks and unable to support bee populations that persist throughout the year. Farm fields and orchards that flower in succession potentially can extend the availability of floral resources for pollinators. However, it is unclear whether the same bee species or genera will forage from one crop to the next, which bees specialize on particular crops, and to what degree inter-crop visitation patterns will be mediated by landscape context. We therefore studied local- and landscape-level drivers of bee diversity and species turnover in apple orchards, blueberry fields and raspberry fields that bloom sequentially in southern Quebec, Canada. Despite the presence of high bee species turnover, orchards and small fruit fields complemented each other phenologically by supporting two bee genera essential to their pollination: mining bees (Andrena spp.) and bumble bees (Bombus spp.). A number of bee species specialized on apple, blueberry or raspberry blossoms, suggesting that all three crops could be used to promote regional bee diversity. Bee diversity (rarefied richness, wild bee abundance) was highest across crops in landscapes containing hedgerows, meadows and suburban areas that provide ancillary nesting and floral resources throughout the spring and summer. Promoting phenological complementarity in floral resources at the farmstead and landscape scales is essential to sustaining diverse wild bee populations.

对商业化授粉（commercial pollination）具有重要价值的野生蜜蜂（wild bees），其生存依赖农田及周边景观中的开花资源与筑巢场所。单一盛花期作物（mass-flowering crops）的花期仅为数周，无法支撑全年存续的蜂群种群。依次开花的农田与果园，或可延长传粉昆虫（pollinators）可获取的开花资源周期。然而目前仍存在诸多待解问题：同一蜂种或蜂属是否会在不同作物间辗转觅食？哪些蜂类会特化取食特定作物？跨作物访花模式在多大程度上会受景观背景（landscape context）调控？为此，我们针对加拿大魁北克南部依次开花的苹果园、蓝莓田与覆盆子田，探究了本地及景观尺度下驱动蜜蜂多样性与物种周转（species turnover）的因素。尽管蜂类物种周转速率较高，但果园与小浆果农田在物候上形成互补——二者分别支撑着两类对授粉至关重要的蜂属：地蜂属（Andrena spp.）与熊蜂属（Bombus spp.）。存在多种特化取食苹果、蓝莓或覆盆子花的蜂种，这表明三种作物均可用于提升区域野生蜜蜂多样性。在景观中包含绿篱（hedgerows）、草地（meadows）与郊区区域的农田中，各类作物的蜜蜂多样性（稀疏化物种丰富度（rarefied richness）、野生蜜蜂多度（wild bee abundance））均处于最高水平，这些景观单元可为春季至夏季全程提供辅助筑巢与开花资源。在农场与景观尺度上强化开花资源的物候互补性，是维持多样野生蜂群存续的关键所在。