Mass-flowering crops: cost or benefit to bumblebees and wild flower pollination?

人们普遍认为传粉媒介正在减少，这威胁到自然植物群落和农业生产力。尽管这种下降最近受到质疑，但大多数权威人士都认为，一些重要的传粉者群体，尤其是大黄蜂，在欧洲的数量和范围都有所下降。在英国，许多植物种类的丰富度也有充分的记录，特别是多年生草本植物，如九脚草和红三叶草。在英国，大规模开花作物（主要是油菜和菜豆）的种植可以说是几个世纪以来对花卉景观最具戏剧性的变化。申请人最近的工作表明，在开花时，这些作物提供的花粉和花蜜的数量大大超过了所有其他昆虫访问的开花植物在耕地景观中提供的总和。然而，对于这种短暂过剩的花卉资源对传粉者种群或野花繁殖的影响，我们仍然知之甚少。大规模开花的作物是否对大黄蜂种群有益，目前还存在分歧（它们提供了大量资源，但蜂群的成功需要整个春夏两季持续的食物供应，而且一些蜜蜂品种不喜欢浅花，比如油菜）。大量开花的作物也可能影响授粉，从而影响可耕种生态系统中野花的结实率。但是目前还不清楚的是，野花是否会因为与作物争夺传粉者而受到不利影响，或者因为这些作物的花粉堵塞柱头，或者相反，它们是否会从当地传粉者数量的增加中受益。答案将取决于作物和野花的物候学和花的相似性。农田野花种群过程及其传粉者种群动态从未在单一项目中同时考虑。该项目旨在利用申请人之前由bbsrc资助的工作，评估大规模开花作物的数量和景观尺度空间分布如何影响传粉者种群（特别是大黄蜂）和野花的繁殖，采用三管齐下的方法：a .研究油菜和菜豆对大黄蜂群体生存的影响，重点研究两种不同的蜜蜂物种，长舌的B. pascuorum和短舌的B. lapidarius。由申请者开创的分子方法将在整个季节用于探测巢穴（Goulson@Stirling）。B.研究这些相同的大开花作物对传粉者访问和五种目标野花的结实率的影响，选择提供一系列物候和花形态（Osborne@Rothamsted） Ci)扩展，开发和测试现有的基于gis的牧草地图和相关模型，以预测可耕地景观中牧草的分布和物候如何决定传粉者的丰度，特别是哪些地区是大黄蜂的储存库。（Sanderson@Newcastle） Cii)使用相同的饲料地图开发新的空间清晰的模型，以检查大规模开花作物对传粉者访问和种子在野花种群中设置的更广泛的景观规模效应。结合起来，这项工作将使我们能够评估种植大规模开花作物对传粉者和野花可能产生的生态后果。并将大大提高我们预测和操纵农业实践对农田生物多样性影响的能力。该项目与制定耕地和农村管理计划的决策者直接相关，例如那些就田地边际管理提供咨询意见的决策者。鼓励大黄蜂大量繁殖的做法将反过来促进作物和野生植物的授粉，从而巩固非农业土地上多样化植物群的可持续性。

There is a widespread perception that pollinators are in decline, and that this threatens both natural plant communities and agricultural productivity. Although this decline has recently been questioned, most authorities agree that some important pollinator groups, notably bumblebees, have declined in both abundance and range in Europe. There are also well documented declines in abundance of many plant species in the UK, particularly perennial herbs such as cowslips and red clover. The cultivation of mass-flowering crops (primarily oilseed rape and field beans) in the UK has been arguably the most dramatic change to the floral landscape for centuries. Recent work by the applicants shows that, when in bloom, the amount of pollen and nectar provided by these crops greatly exceeds that provided by all other insect-visited flowering plants combined in arable landscapes. We still have a poor understanding, however, of the impact that this brief glut of floral resources has on pollinator populations or on the reproduction of wildflowers. There is disagreement as to whether mass-flowering crops are of benefit to populations of bumblebees (they provide a lot of resources, but colony success requires a continuous supply of food throughout spring and summer, and some bee species avoid shallow flowers like oilseed rape). Mass-flowering crops are also likely to affect pollination and hence seed set in wildflowers of arable ecosystems. But it is unclear whether wildflowers will suffer adverse affects from competition with the crop for pollinators or through stigma-clogging with pollen from such crops, or conversely whether they will benefit from a boost to local pollinator populations. The answer will depend on the phenology and floral similarity of crop and wildflower. Wild flower population processes and their pollinators' population dynamics in farmland have never been considered together in a single project. This project aims to capitalise on previous BBSRC-funded work by the applicants, to assess how the amount and landscape-scale spatial distribution of mass-flowering crops affect pollinator populations (particularly bumblebees) and reproduction of wildflowers, using a three-pronged approach: A. Studies of the effects of oilseed rape and field beans on bumblebee colony survival, focussing on two contrasting bee species, the longer tongued B. pascuorum and the shorter-tongued B. lapidarius. Molecular approaches pioneered by the applicants will be used to detect nests through the season (Goulson@Stirling). B. Studies of the effects of these same mass-flowering crops on pollinator visitation and seed-set in five target wildflower species, chosen to provide a range of phenologies and flower morphologies (Osborne@Rothamsted) Ci) Expansion, development and testing of an existing GIS-based forage map and associated model to predict how the distribution and phenology of forage in arable landscapes determines pollinator abundance, and in particular which areas act as sinks for bumblebees, and which act as sources (net exporters of queens) (Sanderson@Newcastle) Cii) Use of the same forage map to develop new spatially-articulate models to examine the broader, landscape scale effects of mass-flowering crops on pollinator visitation to, and seed set in, wildflower populations In combination, this work will enable us to evaluate the likely ecological consequences of growing mass-flowering crops on pollinators and wildflowers, and will substantially increase our ability to predict and manipulate the impacts of agricultural practices on farmland biodiversity. The project is of direct relevance to policy makers producing schemes for arable and countryside stewardship, for example those advising on field margin management. Practices that encourage large bumblebee populations will in turn boost pollination of crops and wild plants, underpinning the sustainability of a diverse flora on unfarmed agricultural land.