Ganser Dominik, Mayr Barbara, Albrecht Matthias, Knop Eva
Institute of Ecology and Evolution University of Bern Bern Switzerland.
Agroscope, Agroecology and Environment Zürich Switzerland.
Ecol Evol. 2018 Nov 6;8(23):11775-11784. doi: 10.1002/ece3.4631. eCollection 2018 Dec.
Wildflower strips (WFS) are increasingly used to counteract the negative consequences of agricultural intensification. To date, it is poorly understood how WFS promote flower visitation and pollination services in nearby insect-pollinated crops. We therefore ask whether WFS enhance pollination service in adjacent strawberry crops, and how such an effect depends on the distance from WFS. Over 2 years, we examined the effects of experimentally sown WFS compared to grassy strips on pollination services in adjacent strawberry () crops across a total of 19 study sites. Moreover, we examined flower visitation, species richness and community composition of the most important insect pollinator taxa at different within-field locations varying in distance to WFS. We found increased pollination services at the edge of WFS compared to locally reduced pollination services at the center, which resulted in no significant difference in seed set between WFS and control fields. Total flower visits and species richness of pollinators were higher in WFS than in adjacent strawberry fields. Moreover, wild bee visitation was enhanced in adjacent strawberry crops near WFS compared to field centers, and intermediate at field edges near grassy strips. Our study demonstrates that diverse WFS can increase wild bee visitation and pollination services in the field edges of adjacent strawberry crops, but that overall visitation and pollination services do not increase. Moreover, our findings show that major pollinator taxa exhibit distinct responses, resulting in a shift of pollinator community composition as a function of distance to WFS with direct effects on crop pollination. Our results that WFS enhance rather than reduce crop pollination services near WFS should distract possible concerns by farmers that WFS may locally absorb rather than export crop pollinators. Considering the spatial restricted enhancement of wild bees and associated pollination services we suggest to establish WFS in the center of crop fields.
野花带（WFS）越来越多地被用于应对农业集约化带来的负面影响。迄今为止，人们对野花带如何促进附近虫媒作物的花朵访花和授粉服务知之甚少。因此，我们研究野花带是否能增强相邻草莓作物的授粉服务，以及这种效果如何取决于与野花带的距离。在两年时间里，我们在总共19个研究地点，对比了实验性播种的野花带与草带对相邻草莓（）作物授粉服务的影响。此外，我们还研究了在距野花带不同距离的田间不同位置，最重要的昆虫传粉类群的花朵访花情况、物种丰富度和群落组成。我们发现，与野花带中心局部授粉服务减少相比，野花带边缘的授粉服务有所增加，这导致野花带与对照田之间的结实率没有显著差异。野花带中传粉者的总访花次数和物种丰富度高于相邻的草莓田。此外，与田中心相比，靠近野花带的相邻草莓作物中野生蜜蜂的访花次数增加，而靠近草带的田边则处于中间水平。我们的研究表明，多样化的野花带可以增加相邻草莓作物田边的野生蜜蜂访花和授粉服务，但总体访花和授粉服务并未增加。此外，我们的研究结果表明，主要传粉类群表现出不同的反应，导致传粉者群落组成随与野花带距离的变化而变化，对作物授粉产生直接影响。我们关于野花带增强而非减少附近作物授粉服务的结果，应能消除农民可能担心的野花带会在局部吸引而非输出作物传粉者的顾虑。考虑到野生蜜蜂和相关授粉服务在空间上的有限增强，我们建议在农田中心设置野花带。
