The association between maintenance and biodiversity in urban green spaces: A review

Most urban green spaces (UGSs) today are under intensive maintenance practices, including mowing, cutting and/or chemical input, among many other practices. An expanding body of research has questioned the biodiversity value of these highly manicured UGSs and has suggested the biodiversity potential of reduced-intensity maintenance regimes. However, the state of evidence for a relationship between maintenance and biodiversity in UGSs is still unclear and yet to be fully understood. This paper systematically reviews 67 published papers to examine this association. Our results revealed a complex association between maintenance and biodiversity, mainly depending on the type of maintenance practice studied and the measurement of biodiversity. Mowing was the predominant maintenance practice under investigation, and more evidence reported a negative association between mowing intensity and various aspects of plant diversity. Similarly, reduced mowing intensity appeared to favour invertebrate diversity, yet many studies have also found mixed associations as well as variations across taxonomic groups. The few studies on chemical input showed a negative association between the use frequency of herbicides/pesticides/insecticides and the diversity of plants, invertebrates, and birds. Nuanced findings, including the possible non-linear association between maintenance intensity and biodiversity, variations in outcomes among different biodiversity indices, and temporal/geographical differences, are here discussed. This review offers insights for developing biodiversity-friendly management strategies and highlights existing research gaps and the need for further research concerning the maintenance-biodiversity link in UGSs.