King's College Cambridge wildflower meadow monitoring data: biodiversity, climate change and society

The biodiversity and climate crises are critical challenges of this
century. Wildflower meadows in urban areas could provide important
nature-based solutions, addressing the biodiversity and climate crises
jointly, and benefitting society in the process. King’s College Cambridge
(England, UK) established a wildflower meadow over a portion of its iconic
Back Lawn in 2019, replacing a fine lawn first laid in 1772. We used
biodiversity surveys, Wilcoxon signed rank, and ANOVA models to compare
species richness, abundance, and composition of plants, spiders, bugs,
bats, and nematodes supported by the meadow, and remaining lawn, over
three years. We estimated the climate change impact of meadow vs lawn from
maintenance emissions, soil carbon sequestration, and reflectance effect.
We surveyed members of the university to quantify the societal benefits
of, and attitudes towards, increased meadow planting on the collegiate
university estate. In spite of its small size (0.36 ha), the meadow
supported approximately three times more plant species, three times more
spider and bug species and individuals, and bats were recorded three times
more often over the meadow than the remaining lawn. Terrestrial
invertebrate biomass was 25 times higher in the meadow compared with the
lawn. Fourteen species with conservation designations were recorded on the
meadow (six for lawn), alongside meadow specialist species. Reduced
maintenance and fertilising associated with meadow reduced emissions by an
estimated 1.36 Mg CO2-e per hectare per year compared with lawn. Relative
reflectance increased by 25-34% for meadow relative to lawn. Soil carbon
stocks did not differ between meadow and lawn. Respondents thought meadows
provided greater aesthetic, educational, and mental well-being services
than lawns. In open responses, lawns were associated with undesirable
elitism and social exclusion (most colleges in Cambridge restrict lawn
access to senior members of the college), and respondents proved
overwhelmingly in favour of meadow planting in place of lawns on the
collegiate university estate. This study demonstrates the substantial
benefits of small urban meadows for local biodiversity, cultural ecosystem
services, and climate change mitigation, supplied at a lower cost than
maintaining conventional lawn.