In the early 1980s, Chalmers University of Technology researcher Roger S Ulrich compared records on recovery after cholecystectomy of 46 patients in a suburban Pennsylvania hospital over the period spanning 1972 to 1981.

Of these, 23 patients had a view out the window with a natural setting (trees, plants etc.). The other 23 saw a brick wall on a neighbouring building.

The outcome? Those with the natural setting had shorter postoperative stays, received fewer negative evaluative comments in nurses notes and took fewer analgesics.

Examples of evidence such as this, RMIT University Professor Sarah Bekessy says, demonstrate the value of biodiversity in urban environments and the need to bring nature back into Australian cities and streets.

In a recent address at a seminar on biodiversity in Melbourne hosted by the Green Building Council of Australia, Bekessy said cities in the past had been seen as a ‘refuge’ from nature and planners and designers had worked to keep natural elements out of our cities.

Now, that is changing and understanding of the opportunities afforded by urban nature is growing.

Bekessy says the challenge is to persuade architects and planners to invite nature into our streets – something she says will be partially addressed through measures such as the proposed introduction of a nature category in the proposed new Green Star Design and As-Built rating tool.

“We are at a critical time in thinking about nature in our cities,” Bekesy says.

“We are moving from a mentality where nature has seen as being a problem in the past and a constraint. Architects have worked hard to keep nature away from us, to keep us ‘safe’ from nature and to make our cities refuges from nature in some respects. That has been the mentality up until this point.”

“We are only just now starting to appreciate that we are critically dependant on nature, we need it in the urban fabric to be able to survive and thrive as a species.

“And so how do we reverse that thinking and get architects and planners to start inviting nature back in, building it into the urban fabric and seeing nature as a massive opportunity to be maximised in every step of the planning process?”

All this is happening as cities grapple with challenges such as clean air, adequate supplies of clean water and remaining habitable during extreme weather – challenges Bekessy says are exacerbated by climate change and population growth.

In her speech, Bekessy outlined six reasons why bringing nature back into our cities is important.

These are as follows:

1) Nature in cities is good for us.

According to Bekessy, the first reason for bringing biodiversity back into our cities is that living, working and playing in and around trees, plants and nature is healthy and beneficial for us as humans.

On this score, she says the Chalmers University study above is one of many which have demonstrated that:

• children who live and play around biodiverse street trees have lower chances of suffering from asthma and allergies
• children whose environments and schoolgrounds feature greater biodiversity have better cognitive and learning outcomes (albeit with one study in the UK suggesting that this is explained more by the higher socio-economic status of families who lived in greener areas rather than the actual greenery itself).
• Adults who interact with nature everyday have lower likelihoods of contracting cancer and heart disease and have a greater likelihood of enjoying better mental health.

Studies with have demonstrated these observations are numerous. A study of more than 200,000 Australians aged 45 years and older, for example, found that those who had more than 20 percent green space  within a one kilometre radius of their home were more likely to walk and participate in activities which are rated as either moderate or vigorous.

2) Future Proofing Against Climate Change

Through means such as shade, reflection of sunlight and the release of moisture into the air through transpiration, nature and trees are critical in addressing urban heat island effects and therefore in future-proofing cities from greater incidences of extreme heat brought about by climate change.

During her talk, Bekessy highlighted thermal imaging of areas immediately surrounding the corner of Bourke Street and Russell Street in Melbourne’s CBD taken on a hot day by Jason Dowling from the University of Melbourne. These showed temperature ranges from less than 30 degrees Celsius in shady areas up to more than 50 degrees on the street and in the open. A similar thermal image of the City of Moreland has identified ‘hotspots’ such as major roads, commercial centres and industrial centres which can reach temperatures of up to 52 degrees Celsius or more even where temperatures in nearby shaded spaces are less than 40 degrees.

All this, Bekessy says, shows the potential for urban nature to help mitigate impacts for vulnerable people within cities on extreme weather days.

3. Nature itself needs it

The third reason for bringing biodiversity back into cities, Bekessy says, is that some species depend on cities for their own survival.

The Frankston spider orchid, for example, is found only in Frankston in Melbourne’s south. Other species use cities as a place of food and other resources. Bringing biodiversity back into cities helps provide a variety of habitats to cater for the different types of species.

This is especially important as many parts of nature currently in urban environments are under threat.

In Melbourne, much grassland in outer urban fringe areas has been lost over recent decades as urban sprawl has taken over. Of that which remains, much is in the likely path of future development.  

An even more poignant example is the Swan Coastal Plain in Perth. This is home to more than 1,500 species of plants, numerous species of forest and woodland birds, mammals, large reptiles and spiders on land as well as more than 130 species of fish in the water and 80 species of waterbirds.

Primarily because of urban development, Bekessy says more than 230,000 hectares of this ecosystem was lost between 1994 and 2004. Between 2011 and 2050, a Swan Coastal Plain South management plan prepared in 2016 notes, further strain is likely as the population of the Peel region is set to double.

4) Reengaging people with nature.

Fourth, Bekessy talks of opportunities to reengage people with nature.

She talks of an ‘extinction of experience’ whereby people who have less contact with nature become disengaged from the natural environment. Many modern children, she says, will recognise thousands of company logos by the time they are adults but will know only a few species of bird.

By bringing nature back into cities, Australia can begin to reverse this.

5) Reconnecting with Indigenous Culture and History

On a further note, Bekessy says many plant an animal species could be used to help tell cultural stories and enhance understanding of Australia’s indigenous history and heritage.

The unfortunately named brown funnel spider, for example, was present throughout Melbourne in large numbers at the beginning of the Wurundjeri settlement and could easily be used to tell cultural stories and connect people with elements of traditional indigenous culture.

At RMIT, Bekessy is part of a team which is working with traditional owners on a project which connects children with nature through a turtle species that involves recreating habitat, bringing species back and telling stories about these species from a cultural perspective.

6) Financial and economic benefits

Finally, there are economic benefits from urban nature.

In 2011, Brisbane City Council estimated that its street trees deliver $1.67 million worth of benefits each year through improving air quality, cleaning and reducing stormwater runoff and storing and sequestering carbon along with delivering a $29.7 million uplift to the overall value of residential property throughout the city’s municipality.

In the US, a 2016 study by the US Forest Service found that every $1 spent in planting or maintaining a street tree throughout the state of California returned an average of $5.82 in benefit. That study put the overall value of tree canopy which lined the state’s streets, avenues and boulevards at around $1 billion. This included $839 million in higher property values, $101 million in energy savings, $41.5 million in catching rainfall, $18 million in removing air pollutants and $10 million in carbon storage.

Green a retail district, Bekessy says, and sales go up. Green business districts and productivity rises.

Around many parts of the country, Australia has an abundance of biodiversity and nature.

For many reasons, it must be brought back into our cities.