08-22-2023

Small greening projects can dramatically boost urban biodiversity

Earth.com staff writer

In the heart of Melbourne, a small green oasis stands as a testament to the potential power of urban greening. A recent study from the University of Melbourne has demonstrated the profound impact small urban greening projects can have on city ecosystems.

By focusing on enhancing the diversity of indigenous plants, the researchers observed a staggering sevenfold increase in insect species in just three short years.

Focus of the study

The central theme of the study, conducted in a greenspace within Melbourne, revolved around the relationship between plant diversity and insect biodiversity.

The results revealed that enhancing the variety and complexity of plant communities significant boosted insect biodiversity, leading to more frequent interactions between plants and insects.

Such findings bolster the increasingly recognized idea that integrating nature into urban environments is not only good for human well-being, but also plays a vital role in enhancing biodiversity and combating the repercussions of climate change.

“Our findings provide crucial evidence that supports best practice in greenspace design and contributes to re-invigorate policies aimed at mitigating the negative impacts of urbanization on people and other species,” said study lead author Dr. Luis Mata.

How the research was conducted

Initially, the site chosen for the study consisted of merely a grass lawn and a couple of trees. However, in a month’s time, weeds were removed, new topsoil was added, the soil was fertilized, and it was layered with organic mulch. The team also introduced 12 indigenous plant species.

Over four years, the researchers conducted 14 meticulous insect surveys, using entomological nets to gather samples from each plant species.

What the researchers discovered

Ultimately, a total of 94 insect species were identified, with an impressive 91 of them being native to Victoria, Australia.

“Most importantly, the indigenous insect species we documented spanned a diverse array of functional groups: detritivores that recycle nutrients; herbivores that provide food for reptiles and birds; predators and parasitoids that keep pest species in check,” said Dr. Mata.

Remarkably, within just a year, the 12 plant species introduced at the study’s outset supported an estimated 4.9 times more insect species than the initial two species that pre-existed in the greenspace.

By the third year, despite a decrease in plant species to nine, they still supported a whopping 7.3 times more insect species than the original greenspace occupants.

Study implications

The broader implications of this study are clear and far-reaching. The adaptable methodology used by the Melbourne team can be replicated in diverse settings and climates, making it a valuable resource for scientists and urban planners around the globe.

“I’d love to see many more urban greenspaces transformed into habitats for indigenous species. We hope that our study will serve as a catalyst for a new way to demonstrate how urban greening may effect positive ecological changes,” said Dr. Mata.

The research is published in the British Ecological Society journal, Ecological Solutions and Evidence.

More about urban greening

Urban greening, an ever-growing trend in contemporary urban design and planning, refers to the introduction or enhancement of vegetation in city settings. It encompasses a broad range of initiatives, from the development of large public parks to the establishment of small community gardens, rooftop green spaces, and even vertical gardens on building facades.

Importance of urban greening

Biodiversity

As the study from the University of Melbourne highlighted, urban greening can significantly boost local biodiversity, providing habitats for various species of plants, insects, birds, and other animals.

Climate change mitigation

Plants absorb carbon dioxide and release oxygen, making urban greening an essential tool in mitigating the effects of climate change. Moreover, vegetation can cool cities through shade and evapotranspiration, reducing the urban heat island effect.

Psychological and health benefits

Green spaces in cities offer residents places to relax, exercise, and connect with nature. Research has shown that exposure to nature can reduce stress, lower blood pressure, and improve mood.

Benefits of urban greening

Air quality

Plants act as natural air purifiers, absorbing pollutants like sulfur dioxide, ammonia, and certain particulate matter, thereby improving urban air quality.