Creating gardens with native plants in the green strips along streets can significantly increase biodiversity in urban areas, according to a study conducted in Merri-bek, in the northern part of Melbourne, Australia. After transforming spaces traditionally occupied by lawns, the abundance of insects was seven times higher and the number of species roughly doubled.
Published in the Journal of Applied Ecology, the University of Melbourne study analyzed the effect of creating gardens designed to provide habitat for pollinating insects in several green strips along the streets. The researchers compared biodiversity before and after the installation of gardens with native plants.
The bees showed the most pronounced response, being associated with the quantity and diversity of flowering plants present in the gardens. Butterflies and beetles also responded positively to the transformation, although the effects were more variable.
“Bees showed the greatest affinity for these gardens and were positively associated with the amount of flowers and the number of different flowering plants,” explains Philippa Bell, a researcher at the University of Melbourne and the lead author of the study.
The researchers consider that roadside green strips can constitute an opportunity to create habitats for pollinators and other animals within the urban fabric. These spaces are often dominated by simplified vegetation and lawns subjected to regular mowing, which provide little shelter and limit flowering.
“Like us, insects need food and shelter to survive and thrive. Traditional green strips with grass offer little shelter and lawns frequently mowed rarely allow plants to flower,” says Bell.
According to the researcher, creating individual gardens is a first step, but coordinated interventions across several green strips could help create more connected habitats and support pollinators.
“Although individual gardens in the green strips are a great start, collective actions to create green spaces in these sites have the capacity to effectively support pollinators in cities,” she states.
The study also points to potential social benefits associated with creating these spaces. With the growth of cities and urban populations, the researchers warn of a decrease in daily contact with nature, a phenomenon that can contribute to greater disengagement from environmental issues.
The landscaped green strips can provide opportunities for contact with plants and animals in the urban space and contribute to a greater connection to nature. The researchers argue that this relationship can also foster behaviors that protect biodiversity.
The study may also provide data to support decisions by local authorities on biodiversity strategies and the creation of urban green spaces. In Melbourne, several municipalities allow residents to create gardens in the green strips along streets, although rules vary between local authorities.
