Loss of wild flowers across Britain matches pollinator decline, first ever Britain wide study reveals
The first ever Britain-wide assessment of the value of wild flowers as food for pollinators shows that decreasing resources mirror the decline of pollinating insects, providing new evidence to support the link between plant and pollinator decline.
In recent years, there have been considerable concerns over threats to wild bees and other insect pollinators which are vital to the success of important food crops and wild flowers.
Amongst the many pressures facing pollinators, a key factor is likely to be decreasing floral resources in Britain.
The study, published today in Nature combines vegetation survey data recorded over the last 80 years with modern day measurements of nectar to provide the most comprehensive assessment ever published.
In the study, researchers from the University of Bristol and University of Leeds worked with scientists from the Centre for Ecology and Hydrology and Fera Science Ltd, to find substantial losses to nectar resources in England and Wales between the 1930s and 1970s – a period closely linked with agricultural intensification.
By 1978, the researchers discovered that nectar resources had stabilised, and actually increased from 2000. The findings complement indications suggesting that declines in pollinator diversity slowed down or partially reversed over that period.
Professor Jane Memmott, University of Bristol, said: “Over the last few decades despite stabilisation, the diversity of nectar sources has declined – a trend seemingly mirrored in the diversity of pollinator species.”
The study also focused on the type of habitats most beneficial for pollinators, highlighting arable land as the poorest source of nectar: both in terms of amount and the diversity of sources. Improved grasslands could however contribute the most to national nectar supply if management favoured greater flowering of plants such as white clover.
Dr Mathilde Baude, lead author, said: “ Nationally, a small number of plants contribute massively to nectar provision including clover, heather and thistles. These very common species are very important to ecosystem functioning, yet they are often disregarded.”
Professor Bill Kunin, University of Leeds, said: “Farmers on Agri-environment schemes can plant wild flowers to help improve the value of their land for pollinators, but the areas involved have been small and thus the contribution to floral resources at the national scale is still low. On the other hand, there are vast areas of improved grasslands, and small changes in management to increase wild flowers could make a huge contribution nationally.”
This study provides new evidence for policy makers to help restore national nectar supplies for our important insect pollinators.
The Insect Pollinators Initiative is joint-funded by the Biotechnology and Biological Sciences Research Council (BBSRC), Defra, the Natural Environment Research Council (NERC), the Scottish Government and the Wellcome Trust. It is managed under the auspices of the Living with Environmental Change (LWEC) partnership.
Notes to editors
Paper: Historical nectar assessment reveals the fall and rise of floral resources in Britain.
- Copyright: Mathilde Baude
- Bell heather (Erica sp.) with the flowers bagged to exclude pollinators so we can collect the nectar produced over a 24 hour period. Copyright: Mathilde Baude
- Nectar extraction from a red campion flower using a microcapillary tube. When the tube touches the nectar it moves up into the tube and the volume is then measured along with the sugar concentration. Copyright: Mathilde Baude
- Fieldwork in action 1 (Mathilde Baude & Nancy Davies – lead author and co-author on the paper) counting the number of flowers per quadrat; Nancy is at the front, Mathilde behind. Copyright: Jane Memmott
- Fieldwork in action 2 (Nancy Davies – co-author, Naomi Dalton – PhD student and Mathilde Baude – lead author). Identifying a plant before doing a flower count. Copyright: Jane Memmott