In urban areas, home gardens are by far the biggest source of food for pollinating insects such as bees, wasps, butterflies, moths, flies, and beetles. Researchers at the University of Bristol have determined that residential gardens account for 85 percent of the nectar produced in cities and towns.
The study revealed that just three residential gardens can generate enough of the sugar-rich liquid Nature’s ambrosia to fuel thousands of flying bees. By supporting more pollinators, the gardens support greater wildlife diversity.
“Although the quantity and diversity of nectar has been measured in the countryside, this wasn’t the case in urban areas, so we decided to investigate,” said study lead author and PhD student Nicholas Tew.
“We expected private gardens in towns and cities to be a plentiful source of nectar, but didn’t anticipate the scale of production would be to such an overwhelming extent. Our findings highlight the pivotal role they play in supporting pollinators and promoting biodiversity in urban areas across the country.”
In collaboration with the universities of Edinburgh and Reading and the Royal Horticultural Society, the researchers was conducted in four major UK towns and cities: Bristol, Edinburgh, Leeds, and Reading.
The team examined nectar production in nearly 200 species of plants by extracting nectar from more than 3,000 individual flowers and measuring sugar concentrations.
“We found the nectar supply in urban landscapes is more diverse, in other words comes from more plant species, than in farmland and nature reserves, and this urban nectar supply is critically underpinned by private gardens,” said Tew.
“Gardens are so important because they produce the most nectar per unit area of land and they cover the largest area of land in the cities we studied.”
Residential gardens made up nearly one-third of the land in the urban areas studied. This is six times the area of parks and 40 times the area of allotments.
According to Tew, the research illustrates the huge role gardeners play in pollinator conservation, as without home gardens there would be far less food for pollinators in towns and cities.
“It is vital that new housing developments include gardens and also important for gardeners to try to make sure their gardens are as good as possible for pollinators,” said Tew.
“Ways to do this include planting nectar-rich flowers, ensuring there is always something in flower from early spring to late autumn, mowing the lawn less often to let dandelions, clovers, daisies and other plant flowers flourish, avoiding spraying pesticides which can harm pollinators, and avoiding covering garden in paving, decking or artificial turf.”
Dr. Stephanie Bird is an entomologist at the Royal Horticultural Society, which helped fund the research.
“This research highlights the importance of gardens in supporting our pollinating insects and how gardeners can have a positive impact through their planting decisions,” said Dr. Bird. “Gardens should not be seen in isolation – instead they are a network of resources offering valuable habitats and provisions when maintained with pollinators in mind.”
The study is published in the Journal of Ecology.
By Chrissy Sexton, Earth.com Staff Writer