Data from: Enhancing gardens as habitats for flower-visiting aerial insects (pollinators): should we plant native or exotic species?

1. Domestic gardens typically consist of a mixture of native and non-native plants which support biodiversity and provide valuable ecosystem services, particularly in urban environments. Many gardeners wish to encourage biodiversity by choosing appropriate plant taxa. The value of native and non-native plants in supporting animal biodiversity is, however, largely unknown. 2. The relative value of native and non-native garden plants to invertebrates was investigated in a replicated field experiment. Plots (deliberately akin to garden borders) were planted with one of three treatments, representing assemblages of plants based on origin (native, near-native and exotic). Invertebrates and resource measurements were recorded over four years. This paper reports the abundance of flower-visiting aerial insects (‘pollinators’) associated with the three plant assemblages. 3. For all pollinator groups on all treatments, greater floral resource resulted in an increase in visits. There was, however, a greater abundance of total pollinators recorded on native and near-native treatments compared with the exotic plots. Short-tongued bumblebees followed the same pattern whilst more hoverflies were recorded on the native treatment than the other treatments, and more honeybees on the near-native treatment. There was no difference between treatments in abundance of long-tongued bumblebees or solitary bees. The lack of difference in solitary bee abundance between treatments was probably due to a third of individuals from this group being recorded on one exotic plant species. 4. The number of flower visitors corresponded to the peak flowering period of the treatments, that is there were fewer flower visitors to the exotic treatment compared with the other treatments in early summer but relatively more later in the season. 5. Synthesis and applications. This experiment has demonstrated that utilizing plants from only a single region of origin (i.e. nativeness) may not be an optimal strategy for resource provision for pollinating insects in gardens. Gardens can be enhanced as a habitat by planting a variety of flowering plants, biased towards native and near-native species but with a selection of exotics to extend the flowering season and potentially provide resources for specialist groups.1. 私人花园通常由本土植物（native plants）与外来植物（non-native plants）混合构成，这类花园可支撑生物多样性并提供宝贵的生态系统服务（ecosystem services），在城市环境中尤为如此。许多园艺爱好者希望通过选择适宜的植物类群（plant taxa）来促进生物多样性，但本土与外来植物对动物生物多样性的支撑价值在很大程度上仍未明确。 2. 本研究通过重复野外试验，探究了花园中本土与外来植物对无脊椎动物（invertebrates）的相对价值。实验地块（设计上模拟花园花境）被分为三组处理，每组对应基于植物起源划分的植物组合：本土植物（native）、近本土植物（near-native）与外来引种植物（exotic）。研究团队连续四年记录了地块中的无脊椎动物种群与相关资源量测定数据。本文聚焦并报告了与这三类植物组合相关的访花飞行昆虫（‘传粉昆虫（pollinators）’）的丰度。 3. 针对所有处理组下的各类传粉昆虫类群而言，花部资源量越高，昆虫访花频次也随之增加。但相较于外来引种植物组，本土与近本土植物组的总传粉昆虫丰度显著更高。短舌熊蜂的响应模式与此一致：食蚜蝇在本土植物处理组中的丰度高于其余两组，而蜜蜂在近本土植物处理组中丰度更高。长舌熊蜂与独居蜂的丰度在三组处理间无显著差异。独居蜂丰度无组间差异的原因可能在于，该类群中有三分之一的个体仅在一种外来引种植物上被记录到。 4. 访花昆虫的数量与各处理组的盛花期高度吻合：即初夏时节，外来引种植物组的访花昆虫数量少于其余两组，但在该生长季后期，其访花昆虫数量相对更多。 5. 总结与应用。本实验表明，仅选用单一起源的植物（即仅依赖本土性植物），或许并非为花园传粉昆虫提供食物资源的最优策略。通过种植多样的开花植物可改善花园的栖息地质量：优先配置本土与近本土物种，同时搭配部分外来引种植物以延长整体花期，并可为特化昆虫类群提供潜在的食物资源。