STOP MOWING! INCREASE IN SPECIES DIVERSITY WITH CHANGES IN THE MANAGEMENT OF AN URBAN LAWN

Intensively managed lawns designed for recreational use are common in urban landscapes but require considerable maintenance and usually harbor low plant diversity. Alternative management proposals for lawns are increasingly encouraged, but to introduce them, it is necessary to understand their potential for plant diversity. The objective of this study was to evaluate the effects of interrupting mowing on the plant community, in terms of structure, composition, and diversity in an area for experimental purposes previously considered as lawn in the Botanical Garden of Porto Alegre, state of Rio Grande do Sul, Brazil. A quantitative survey of the vegetation was carried out in three types of management in the experimental area, developed after the end of the mowings: frequently mowed grassland; grassland unmanaged for two years (unmowed grassland); and grassland unmanaged for two years with a strong presence of the invasive species Urochloa decumbens (unmowed invaded grassland). Sampling was conducted with the allocation of 24 plots 1m². We used the Adonis2 and Pairwise Adonis2 analyzes to verify significant differences between the management classes and we related the classes to the structural variables and the floristic composition through redundancy analysis (RDA). The management classes were distinct from each other in terms of structure, composition and species diversity, with the unmowed grassland presenting the higher richness of species and life forms. Annual, rosette and exotic species reveal the ruderalization of the study area. The interruption of mowing could offer high potential for a more diverse grassland species community, even considering the presence of invasive alien species. Understanding the effects of cutting management through mowing in lawn areas is essential for conserving plant diversity in urban spaces and for valuing native landscape potential.