Nectar production was measured in nearly 200 plant species by extracting nectar from more than 3,000 individual flowers.
Mr. Tew, who is studying for a PhD in ecology, said, “We have found that urban nectar supplies are more diverse, in other words – (it) comes from more plant species than farmland and nature reserves, and that urban nectar supply is becoming critical underpinned by private gardens. “
“Gardens are so important because they produce the largest nectar per unit area and cover the largest area of land in the cities we studied.”
A fine glass tube was used for extraction and the sugar concentration of the nectar was quantified with a refractometer – a device that measures how much light is refracted as it passes through a solution.
A total of 29% of land in urban areas is made up of indigenous gardens – six times the area of parks and 40 times the area of allotment gardens.
Mr Tew said it was vital for new housing developments to include gardens and urged gardeners to ensure their spaces are “as good as possible” for pollinators.
He suggested planting nectar-rich flowers to make sure there was always something in bloom from early spring to late fall, and mowing the lawn less often to allow dandelions, clover, daisies, and other plants to grow.
Gardeners should also avoid spraying pesticides, as these can damage pollinators, and avoid covering their gardens with paving stones, patios or artificial grass, he said.
Dr. Stephanie Bird, Insect Scientist at the Royal Horticultural Society, said, “This study underscores the importance of gardens in supporting our pollinating insects and how gardeners can make positive impacts through their planting decisions. Gardens should not be viewed in isolation – instead, they are a network of Resources that provide valuable habitats and supplies, when cared for with pollinators in mind. “
The paper Quantifying Nectar Production by Flowering Plants in Urban and Rural Landscapes was published in the Journal of Ecology.