Historical nectar assessment reveals the fall and rise of floral resources in Britain.
Historical nectar assessment reveals the fall and rise of floral resources in Britain.
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DOI：
10.1038/nature16532
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发表时间：
2016-02-04
期刊：
影响因子：
64.8
通讯作者：
Memmott J
中科院分区：
文献类型：
--
作者：
Baude M;Kunin WE;Boatman ND;Conyers S;Davies N;Gillespie MA;Morton RD;Smart SM;Memmott J
昆虫传粉者群落的减少以及对农作物和野花授粉的潜在影响引起了相当大的关注。在传粉者面临的多重压力中，栖息地丧失和退化导致的花卉资源减少被认为是一个关键因素。然而，缺乏定量数据阻碍了对花卉资源历史变化的测试。在这里，我们表明，通过结合植被调查和直接花蜜测量，可以在全国范围内估计总体花卉回报。我们发现有证据表明，在20世纪30年代至70年代，英格兰和威尔士的花蜜资源大幅减少；然而，英国的花蜜供应总量到1978年稳定下来，从1998年到2007年有所增加。这些发现与传粉者多样性的趋势一致，传粉者多样性在20世纪中期下降，但最近稳定下来。从1978年到1990年，花蜜来源的多样性有所下降，但此后稳定在较低水平，2007年四种植物占全国花蜜供应量的50%以上。石灰性草地、阔叶林和中性草地是单位面积上花蜜产量最多的生境，来源最多样化，而耕地在这两方面都是最差的。虽然农业环境计划为耕地景观增加了资源，但它们在全国范围内的贡献很低。由于面积较大，如果设法增加花卉资源的供应，改良的草原可以大大增加国家的花蜜供应。这项全国性的花卉资源供应评估为植物和传粉者衰退之间的联系带来了新的见解，并为保护提供了相当大的机会。
There is considerable concern over declines in insect pollinator communities and potential impacts on the pollination of crops and wildflowers. Among the multiple pressures facing pollinators, decreasing floral resources due to habitat loss and degradation has been suggested as a key contributing factor. However, a lack of quantitative data has hampered testing for historical changes in floral resources. Here we show that overall floral rewards can be estimated at a national scale by combining vegetation surveys and direct nectar measurements. We find evidence for substantial losses in nectar resources in England and Wales between the 1930s and 1970s; however, total nectar provision in Great Britain as a whole had stabilised by 1978, and increased from 1998 to 2007. These findings concur with trends in pollinator diversity, which declined in the mid-20th century but stabilised more recently. The diversity of nectar sources declined from 1978 to 1990 but stabilised thereafter at low levels, with four plant species accounting for over 50% of national nectar provision in 2007. Calcareous grassland, broadleaved woodland and neutral grassland are the habitats that produce the greatest amount of nectar per unit area from the most diverse sources, whereas arable land is the poorest in both respects. While agri-environment schemes add resources to arable landscapes, their national contribution is low. Due to their large area, improved grasslands could add substantially to national nectar provision if they were managed to increase floral resource provision. This national-scale assessment of floral resource provision brings new insights into the links between plant and pollinator declines, and offers considerable opportunities for conservation.