Impact of Mowing Frequency on Arthropod Abundance and Diversity in Urban Habitats

Abstract

Urbanization is an important driver of global insect decline. Yet, recent studies have demonstrated the potential of greenspaces in cities to promote biodiversity conservation. One of many factors negatively affecting arthropods in urban areas are unsuitable habitats, as non-woody greenspaces predominantly consist of manicured lawns. Maintenance practices such as high mowing frequencies, can have direct and indirect negative impacts on the local flora and fauna. The present study examines the effects of different mowing regimes on arthropod abundance and diversity by conducting meta-analyses of studies assessing the effect of mowing on arthropod abundance (46 datasets) and taxa richness (23 datasets) in urban environments. While our meta-analysis on arthropod abundance showed a medium positive effect (effect size: g = 0.54) of reduced mowing, the cumulative effect of reduced mowing on arthropod taxa richness was large (g = 1.25). Grouping the studies not only resulted in lower heterogeneity, but also showed that manicured lawns disproportionately favor “pest” species. While most studies assess biodiversity change based on abundance (individual counts), biomass might be a more meaningful bioindicator that can be estimated with similar effort. Overall, the findings of the present meta-analyses strongly support the notion that a reduction in mowing frequencies in urban greenspaces benefits insect biodiversity.

Keywords: Urban lawn, Greenspace management, Arthropods, Urban green space, Urban biodiversity, Insect decline