These tiny pollinators have been essential in understanding how the UK’s fields, hedgerow, wild spaces, gardens have changed since the 1950’s.
By using cutting-edge DNA barcoding techniques, scientists at the National Botanic Garden of Wales have identified the plants honeybees appear to favour by looking at the pollen grains trapped within honey.
The differences were clear. White clover had been the most important plant for honeybees but, with fewer pastures today and increased use of herbicides and inorganic fertiliser in farming, this has dropped to second place. Now the insects are visiting much more of:
- bramble – their modern-day favourite
- oilseed rape, a plant with a sting in its tail
- the invasive Himalyan balsam
Dr. Natasha de Vere, Head of Conservation and Research at the National Botanic Garden of Wales, said: “The last 65 years have been a period of profound change within the UK landscape. Agricultural intensification after the Second World War led to a decline in species-rich grasslands and permanent pastures, while hedgerows and woodland were destroyed so that field sizes could increase. The distribution and abundance of the UK’s wildflowers has changed, with some species declining whilst new plants have been introduced.
White clover was the most important plant for honeybees in 1952, found in 93% of honey samples. However, by 2017 white clover was a major source in just 31% – a sign that our modern-day landscape has far less white clover.
The countryside survey for the UK has shown that between 1978 and 2007 white clover decreased within the landscape by 13%.
After the reduction of an important nectar source, honeybees turned to Bramble – which was found in 73% of honey samples.
Himalayan Balsam was first introduced to the UK in 1839. Making its escape from the garden walls and increasing more rapidly from the 1940s to the 1960s, Himalayan Balsam gradually established itself along waterways and field margins. In 2017 it was found within 15% of samples.
Though obviously a great plant for the honeybee, this species is highly invasive, listed under Schedule 9 of the Wildlife and Countryside Act 1981, making it an offence to plant or cause this species to grow in the wild.
Dr. de Vere added: “Honeybees and wild pollinators need abundant and diverse sources of nectar and pollen within the landscape, to provide sufficient, high-quality food.
“By understanding which plants are the most important sources we can provide recommendations on which plants to grow so that honeybees and wild pollinators can thrive.”
The conversation of remaining species-rich meadows is essential, but unfortunately the area these habitats cover is vanishing small. Wildflowers are squeezed out to create grasslands dominated by a small number of grass species, where there are very few flowers to sustain pollinators.
To make the biggest gains in nectar and pollen, changes are needed in the most prevalent habitat in the UK today—improved grassland.
For honeybees, providing more white clover in improved grasslands is key.