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. A growing body of research has questioned the biodiversity value of highly manicured UGSs and suggested the biodiversity potential of reduced-intensity maintenance regimes. However, the evidence for a relationship between maintenance and biodiversity in UGSs is still unclear and yet to be fully understood. This paper systematically reviews 92 published papers to examine this association. Our results showed a complex association between maintenance and biodiversity, mainly dependent on the type of maintenance practice studied and the measurement of biodiversity. Mowing was the predominant maintenance practice that had been investigated, and the evidence from these papers constantly 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 also found mixed associations as well as variations across taxonomic groups. The few studies on chemical input showed a negative association between the frequency of use of herbicides/pesticides/insecticides and the diversity of plants, invertebrates, and birds. Nuanced findings, including a non-linear association between maintenance intensity and biodiversity, and temporal/geographical differences, are discussed in this paper. This review offers insights for the development of biodiversity-friendly management strategies, highlighting existing research gaps and the need for further research concerning the maintenance-biodiversity link in UGSs.