Lawns feel unnatural and provide little feeling of being in nature – could urban meadows be the answer?
Urban areas have been noted as a contributing factor to both the climate and biodiversity crises.
Wildflower meadows can be grown to mitigate both of these issues while providing benefits to human well-being; I mean, who doesn’t love taking a stroll through a meadow?.
Currently, 25% of UK urban areas are made up of grasslands, largely consisting of small patches, with approximately half of these spaces being private gardens.
These lawns are generally carefully managed, species-poor areas made up of perennial ryegrass. This is due to their easy establishment and recreational benefits like a good old game of footy.
While lawns and wildflower meadows are both considered semi-natural grasslands, lawns generally require more maintenance, with regular mowing (ugh) and application of water and pesticides in some cases.
Though wildflower meadows do not provide the same type of usable space that lawns do, they do have their benefits. These include greater above and below-ground biodiversity, a greater capacity for carbon sequestration and increased human perception of green space compared to a managed lawn.
To try and harness these benefits, in 2019, King’s College Cambridge replaced part of a lawn with a wildflower meadow, hoping to increase biodiversity and reduce greenhouse gas (GHG) emissions while providing recreational benefits to the community.
A recent study evaluated the success of the meadow compared to the adjacent lawn, looking at three key aspects; wildlife value, climate change mitigation and societal benefits.
Establishment and sampling
Following soil analysis to determine pre-meadow data of pH and fertility, the soil was prepared with herbicide and planted with three different seed mixes.
Once established, the meadow was managed following traditional practices as much as possible.
Hay was cut twice a year in August and December to mimic light grazing; weeding was conducted during the visitor season to get rid of the odd unwanted plant species.
The adjacent traditional lawn required more maintenance. It received twice-weekly cuts from March to September, weekly cuts from October to December and cuts every other week in January and February. Herbicide was applied twice a year and the lawn was watered only when necessary.
Plant surveys were carried out on the lawn and meadow before the meadow was sown and the two subsequent summers. Measurements recorded using quadrats included identifying plant species present and the presence or absence of a species in each quadrat.
Above-ground invertebrates were sampled using a sweep net and pitfall traps placed at the centre of each quadrat location, with most specimens being identified at species level.
Bat presence was recorded using remote ultrasonic devices in 2021 during the summer months.
To determine how the meadow might mitigate against climate change, high-resolution imaging and soil organic matter measurements were taken to measure carbon sequestration and carbon dioxide emissions. Albedo (the amount of light and therefore heat a body or surface reflects) was also measured by comparing relative reflectance values of the lawn and meadow.
Finally, a survey was conducted in 2021 to assess people’s opinions on the cultural services provided by the lawn and meadow.
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Impacts on wildlife
Despite its small size and recent establishment, the meadow proved to be a haven for wildlife compared to the lawn.
The data showed it was supporting roughly three times more plant species, leading to three times more species and individuals of insects and spiders present.
The meadow also attracted specialist insect species, including a type of mirid bug that feeds on the umbels of wild carrots.
In fact, insect biomass was 25 times higher in the wildflower meadow than on the lawn.
Fourteen insect species with conservation designations were recorded in the meadow, along with a plant and fungal species never before recorded in Cambridgeshire: the eyebright species Euphrasia confusa, and the microfungus Cercospora zebrina on Medicago arabica.
Sward height and average insect body length were both larger in the meadow than on the lawn, suggesting that larger insect species were able to survive in the meadow due to increased protection from bird predation.
Increased plant diversity influences the entire ecosystem, as reflected here in bat activity, which increased three-fold over the meadow and the lawn, thanks to the increase in insect diversity associated with greater plant diversity.
All this suggests that restoring species-rich meadows can have more than a little positive effect on urban ecosystems, simply by increasing plant diversity and sward height.
Climate change mitigation
The meadow had reduced carbon emissions compared to the lawn by approximately 1.36 tonnes per hectare, thanks to reduced maintenance and fertilising. The reduced emissions were only small compared to the College’s overall output, but the associated management reductions did provide a saving of £650/ha/year.
No significant differences in soil carbon between the lawn and meadow were recorded in the top 10 cm of soil, though deeper rooted plants may have increased carbon levels deeper than 10 cm. Detecting changes in soil carbon over a short space of time is challenging unless sampling is extremely thorough or changes in carbon levels are significant.
The meadow reflects 25% to 34% more light than the lawn. Even unmown lawns reflect 25% more light than well-maintained ones, suggesting maintenance affects reflectance more than plant types. Therefore, changing maintenance or adding meadow areas could increase reflectance and keep urban areas cooler in the future.
Societal views
Survey respondents preferred meadows over lawns for their aesthetic appeal, educational value and mental well-being benefits. They also felt meadows had a stronger cultural and spiritual connection and were more inspiring.
However, they rated lawns higher for recreational and practical use, highlighting the need for diversity in urban green spaces.
A balance should be struck between what is best for people and what is best for wildlife. Clearly, we need somewhere to picnic and play as well as somewhere to soak in the delights of uncultivated nature.
Ensuring the public is comfortable is essential when lawn spaces are transformed into meadows, said Dr Cicely Marshall who headed the Cambridge project. “Take concerns over safety and maintenance seriously, so some initial signage to explain what’s happening, maintain sight lines so visitors still feel safe in a potentially less open space.”
Survey respondents showed a preference for a combination of lawn and meadow spaces, with paths and seating areas located within the meadows.
Similar responses were noted in Sweden, where people valued the variety that meadows provide the senses but enjoyed the recreational uses that lawns provide, for picnicking, playing etc.
Overall, the establishment of urban meadows can provide many benefits to people, the climate and wildlife alike. Even on a small scale, they can help to reduce CO2 emissions and provide a habitat for vulnerable species.
Would you like to see more meadows in your local parks and open spaces?