Biodiversity benefits of wildflower meadow at King’s College, Cambridge, are revealed

The results of King’s College’s decision to allow a section of its lawn to grow wild have been revealed - and it is hoped it will encourage others to follow suit.

The University of Cambridge college broke with tradition in 2020 when, for the first time since it was laid in 1772, the mowers avoided an area of its usually pristine lawn - the size of half a football pitch.

A colourful wildflower meadow filled with poppies, cornflowers and oxeye daisies sprung up and other plants emerged in the following years as the lawn began to transform into an East Anglian hay meadow, which was eventually mown at the start of August in traditional style, with two Shire horses, and the resulting bales were shared with other Cambridge colleges so they could start their own meadows.

Dr Cicely Marshall, a researcher at King’s and the University of Cambridge’s Department of Plant Sciences, has studied the effects, finding the meadow boosted biodiversity and was more resilient than lawn to our changing climate.

She discovered that the wildflower meadow supported three times more species of plants, spiders and bugs than the remaining lawn, including 14 species with conservation designations, compared with six in the lawn.

“We found that the meadow was strikingly beneficial for biodiversity. I was really surprised, actually, at the magnitude of the change for such a small area,” said Dr Marshall.

During sampling, 84 plant species were counted, of which only 33 had been sown, with the rest appearing naturally. Some 16 bug and spider species were found, 149 nematode (roundworm) genera and eight species of bat.

“We found that bats are foraging three times more often over the meadow than over the lawn. For species that might look for insects over several miles in a single evening, it’s incredible that our small meadow impacted their behaviour,” said Dr Marshall.

By reducing mowing and fertilisation, the meadow saved an estimated 1.36 tonnes of carbon emissions per hectare per year.

As climate change makes growing seasons longer, and the number of cuts required to maintain a pristine lawn rises, the comparison will grow starker.

The meadow also reflected 25 per cent more sunlight than the lawn, helping to counteract the ‘urban heat island’ effect by which cities heat up more than rural areas.

“Cambridge has become more prone to drought, and last summer most of the college’s fine lawns died. It’s really expensive to maintain these lawns, which have to be resown if they die off. But the meadow just looked after itself,” said Dr Marshall.

“Wildflowers tend to have deeper roots than grass, so are less likely to die during prolonged dry spells.”

In a survey by the team, 278 respondents were overwhelmingly in favour of more meadows, noting benefits to mental wellbeing and the environment, and educational value, while pointing out the continued need for lawns for recreation.

The meadow was the idea of Steve Coghill, head Gardener at King’s, and fellow Prof Geoff Moggridge, whose proposal was approved by college committees in 2018 for a five-year trial period. But he is confident the meadow is now here to stay.

“The meadow is starting to mature – you can see the cowslips now, and by June-July it’s going to be absolutely beautiful,” he said. “We’ll cut paths through it again this year for visitors to walk through, to have the joy of being surrounded by what is essentially an East Anglian hay meadow in the centre of Cambridge.”

And he hopes more householders may be inspired to follow suit.

“Many people mow their lawns because that’s what they’ve always done. There’s a perception that a close-mown lawn demonstrates you’re caring for the garden more,” he said. “And sometimes it’s the historically appropriate thing to do. At King’s we also have closely mown lawns because they’re in keeping with the historical period reflected by our buildings.

“But we’re not frightened to be contrary at King’s, and for all the right reasons. Britain is one of the most deforested countries in Europe. Anything we can do to bring back some biodiversity is worth a go.”

Dr Claudia Schneider, a researcher in the University’s Department of Psychology, notes that having information is not always enough to motivate people to change their behaviour, although it is an important first step.

Her paper, in the journal One Earth outlines the power of social norms in motivating collective action on climate change.

“People are very influenced by what others around them do, and what the accepted behaviour is, so if neighbours or friends all have lawns, that can be a barrier to creating a wildflower meadow. Humans have a strong need to belong and feel accepted,” she said.

Lawns arose in Europe in the 1770s as a demonstration of wealth and status.

“Research shows that people can be averse to change and the uncertainty that comes with it, unless there’s a strong motivation to do something differently,” said Dr Schneider.

But she added: “People who take the first step can help others to see the benefits. Well-respected, prominent institutions like King’s College can act as role models that may influence public opinion.”

And if you want to show you’re doing it deliberately and not neglectfully, you could always mow paths or a strip around the edge - as edges provide important habitat for wildlife too.