Department of Ecology, Swedish University of Agricultural Sciences , Uppsala , Sweden.
School of Agriculture, Policy and Development, University of Reading , Reading , UK.
PeerJ. 2014 Mar 27;2:e328. doi: 10.7717/peerj.328. eCollection 2014.
Background. Up to 75% of crop species benefit at least to some degree from animal pollination for fruit or seed set and yield. However, basic information on the level of pollinator dependence and pollinator contribution to yield is lacking for many crops. Even less is known about how insect pollination affects crop quality. Given that habitat loss and agricultural intensification are known to decrease pollinator richness and abundance, there is a need to assess the consequences for different components of crop production. Methods. We used pollination exclusion on flowers or inflorescences on a whole plant basis to assess the contribution of insect pollination to crop yield and quality in four flowering crops (spring oilseed rape, field bean, strawberry, and buckwheat) located in four regions of Europe. For each crop, we recorded abundance and species richness of flower visiting insects in ten fields located along a gradient from simple to heterogeneous landscapes. Results. Insect pollination enhanced average crop yield between 18 and 71% depending on the crop. Yield quality was also enhanced in most crops. For instance, oilseed rape had higher oil and lower chlorophyll contents when adequately pollinated, the proportion of empty seeds decreased in buckwheat, and strawberries' commercial grade improved; however, we did not find higher nitrogen content in open pollinated field beans. Complex landscapes had a higher overall species richness of wild pollinators across crops, but visitation rates were only higher in complex landscapes for some crops. On the contrary, the overall yield was consistently enhanced by higher visitation rates, but not by higher pollinator richness. Discussion. For the four crops in this study, there is clear benefit delivered by pollinators on yield quantity and/or quality, but it is not maximized under current agricultural intensification. Honeybees, the most abundant pollinator, might partially compensate the loss of wild pollinators in some areas, but our results suggest the need of landscape-scale actions to enhance wild pollinator populations.
背景。多达 75%的作物物种在果实或种子形成和产量方面至少在某种程度上受益于动物授粉。然而，许多作物的授粉依赖程度和授粉对产量的贡献的基本信息仍然缺乏。关于昆虫授粉如何影响作物质量的了解就更少了。鉴于栖息地丧失和农业集约化已知会降低传粉者的丰富度和数量，因此需要评估其对不同作物生产环节的影响。方法。我们使用花朵或整个植株上花序的授粉隔离来评估昆虫授粉对欧洲四个地区的四个开花作物（春油菜、田豆、草莓和荞麦）的作物产量和质量的贡献。对于每种作物，我们在十个田间记录了访问花朵的昆虫的丰度和物种丰富度，这些田间沿着从简单到异质景观的梯度分布。结果。根据作物的不同，昆虫授粉使作物的平均产量提高了 18%至 71%。在大多数作物中，产量质量也得到了提高。例如，当油菜得到充分授粉时，其油分含量更高，叶绿素含量更低，荞麦中的空粒比例减少，草莓的商业等级提高；然而，我们没有发现开放授粉的田豆中的氮含量更高。复杂的景观在跨作物的野生传粉者整体物种丰富度更高，但某些作物的访问率仅在复杂的景观中更高。相反，更高的访问率始终能提高整体产量，但不会提高传粉者的丰富度。讨论。对于本研究中的四种作物，传粉者在产量数量和/或质量上明显有益，但在当前农业集约化的情况下，这种益处并没有最大化。最丰富的传粉者——蜜蜂，可能在某些地区部分补偿了野生传粉者的损失，但我们的结果表明需要采取景观尺度的行动来提高野生传粉者的数量。
