The Impacts of ‘No-Mow’ Areas on Floral Diversity: A Case Study at the University of Otago

This report explores how mowing cessation impacts floral diversity at the University of Otago. The primary objective was to determine if there is a significant difference in plant species richness between mown and unmown areas on campus. By evaluating the biodiversity benefits of reduced lawn maintenance, the study aims to inform future landscaping practices at the university. Proximal mown and unmown areas across three sites were compared for floral diversity, with all vascular plants recorded within each. A paired t-test evaluated if unmown areas had significantly more plant species than mown areas. Summary statistics quantified findings and guided recommendations. A total of 98 distinct plant species were identified, with 94 present in unmown areas, and 22 in mown areas. The mean taxon richness in unmown areas was 43 species, compared to just 14 species in mown areas. Significant differences were detected between groups, with unmown areas richer in floral taxa (p = 0.01). These results exemplify the benefits of reduced mowing on floral diversity. However, there was no discernible difference in the proportions of native and exotic species. Despite this, urban green spaces are considered ‘novel ecosystems’, supporting humans and fauna in urban centres regardless of species’ origin. Challenges to encouraging diversity include weed and pest mammal threats and biosecurity risks, which may suppress the reported benefits. Cultural perceptions of beauty influence urban grassland maintenance. The European history of the lawn reflects a harmful ideology that suppresses both diverse biota and peoples. The re-wilding of the urban lawns offers an opportunity for campuses and cities to create inclusive spaces for everyone – tāngata whenua and tāngata tiriti. This report underscores that reduced mowing can create biodiversity refuges in little-used corners of greenery in urban centres. However, careful management is needed to address the challenges presented by these novel ecosystems.