Pollination is a vital ecosystem service in urban agriculture. Yet the environmental drivers of both crop and wild plant pollination in urban agroecosystems are still not well understood. Pollination experiments involve the manipulation of pollen transfer between plants, for instance, to study the effects of pollinators on fruit and seed production (pollination service). In this study, we conducted a pollination exclusion experiment using four experimental plants: two cultivated plant species, strawberry (Fragaria x ananassa) and chili pepper (Capsicum frutescens), and two wild plant species, buttercup (Ranunculus acris) and clover (Trifolium pratense). We placed experimental plants for over 20 days in 13 urban community gardens in Munich, Germany. We compared fruit and seed mass between “open” and “bagged” flowers and tested the effect of biotic factors (floral resources and pollinator diversity) and abiotic factors (urbanization, microclimate) on pollination service (fruit and seed mass) on the experimental plant species. For the two cultivated plants (F. ananassa and C. frutescens), we found that fruit and seed mass were both positively correlated with temperature and pollinator diversity. For the two wild plants (R. acris and T. pretense), we found that floral abundance was negatively related to R. acris seed mass but was positively related to T. pratense seed mass. In summary, we found that biotic and abiotic parameters affected the plant species studied here in different ways, suggesting that there may be synergies and trade-offs in what factors promote the overall pollination of urban plant communities. Our results suggest that gardeners can potentially increase the pollination services on certain garden plants by providing floral resources for pollinating insects.

授粉是城市农业中重要的生态系统服务。然而，城市农业生态系统中农作物和野生植物授粉的环境驱动因素仍不清楚。授粉实验涉及植物之间花粉转移的操作，例如，研究授粉媒介对果实和种子生产的影响（授粉服务）。在这项研究中，我们使用四种实验植物进行了授粉排除实验：两种栽培植物，草莓（Fragaria x ananassa）和辣椒（Capsicum frutescens），以及两种野生植物，毛茛（Ranunculus acris）和三叶草（Trifolium pratense））。我们在德国慕尼黑的 13 个城市社区花园中放置了 20 多天的实验植物。我们比较了“开放”花和“袋装”花之间的果实和种子质量，并测试了生物因素（花资源和传粉媒介多样性）和非生物因素（城市化、小气候）对实验植物授粉服务（果实和种子质量）的影响物种。对于两种栽培植物（F. ananassa和C. frutescens），我们发现果实和种子质量均与温度和传粉媒介多样性呈正相关。对于两种野生植物（R. acris和T. pretense），我们发现花丰度与R. acris种子质量呈负相关，但与T. pratense种子团。总之，我们发现生物和非生物参数以不同的方式影响这里研究的植物物种，这表明促进城市植物群落整体授粉的因素可能存在协同作用和权衡。我们的结果表明，园丁可以通过为授粉昆虫提供花卉资源来潜在地增加某些园林植物的授粉服务。