If you want evidence for the importance of gardens for wildlife, just look at the Biodiversity in Urban Gardens in Sheffield (BUGS) project, run by researchers from the University of Sheffield in the early 2000s.
What they found was ground-breaking – 33km² of potential wildlife habitat covering 23 per cent of the city, with an estimated 360,000 trees more than 2m tall, 45,000 nestboxes, 25,000 ponds, and 50,000 compost heaps.
In surveys in 61 of those gardens, the researchers identified 1,166 vascular plant species – the most biodiverse contained 248 alone. There was a rich profusion of invertebrates from a wide range of taxonomic groups, including bumblebees, hoverflies, beetles and spiders.
But, says professor Kevin Gaston – previously the lead investigator on the BUGS project, now at the University of Exeter – you cannot compare the species richness of domestic gardens with that of ancient woodlands or extensive wetlands.
Gardens will compare well with much of our farmland (which covers some 70 per cent of the entire country), because this is species-poor and with low abundance where it is intensively cultivated, Gaston points out.
“Gardens are not routinely going to be havens for species of high conservation concern,” Gaston says. “But that’s not the relevant issue – a stronger argument is that, given the amount of house-building that is happening now, and in the future, how can we make sure that those gardens are as good for wildlife as possible?”
Gaston adds: “The other thing to think about is how gardens increase people’s positive engagement with wildlife. Something that has come through in recent years is the health and well-being impacts of interacting with nature and the role gardens play in that. Wildlife gardening has benefits for householders that transcend the wildlife itself.”
But what should those who want to maximise the contribution of their garden to British Biodiversity PLC do? “The simplest thing you can do is introduce more three-dimensional complexity,” says Gaston. “Vegetation of different types and different forms. Everyone can contribute – that’s the key message,” Gaston concludes.