Recognising lawns as a part of “designed nature”. Pioneering study of lawn’s plant biodiversity in Australian context

Lawns in the twenty-first century dominate urban green infrastructure, fulfilling ecosystem services and functioning as a social, cultural, and ecological phenomenon. This study is the first in Australia to combine field surveys and spatial analysis of lawn distribution and plant biodiversity across the Perth-Peel metropolitan area, Western Australia. It is part of the interdisciplinary project, “Lawns as a Cultural and Ecological Phenomenon in Perth.” Using CSIRO’s Urban Monitor, maps of lawn coverage were developed. Additionally, plant biodiversity was assessed in 320 plots (50 cm × 50 cm) across three lawn typologies: large parks, small parks, and verges. Biodiversity was analysed using species richness and the Shannon Index. Lawns in private gardens and verges accounted for the largest category (53%), followed by smaller parks (37%). Forty two plant species were recorded, dominated by non-native lawn grasses such as Cenchrus clandestinus and Cynodon dactylon. Seasonal influences were significant, with winter (wet season) showing greater biodiversity and coverage than in summer (dry season). Irrigation and mowing frequency are important factors which influence plant biodiversity. Verges demonstrated the highest diversity, especially of annuals in winter. The search for environmentally friendly lawns in Perth should have different approaches from European countries and the USA where a new generation of more biodiverse lawns are usually inspired by the natural and semi-natural grasslands. We suggest pathways of replanning and redesigning urban open spaces with more biodiverse, waterwise and complex lawns and grass-dominated plant communities for Perth. Our results on Perth’s lawn coverage and plant biodiversity of lawns have supported the data from other studies that lawns are one of the most common and globally homogenised and standardised type of urban biotopes.