New protocol could help build biodiverse cities

A new protocol has been released by RMIT University to help developers create urban environments that are beneficial to biodiversity.

The Biodiversity Sensitive Urban Design protocol aims to help bring about green cities that not only protect the environment, but also provide health benefits to its inhabitants.

It is based on five principles: maintaining or creating habitat for target species; facilitating dispersal of species; minimising disturbance; facilitating natural processes; and facilitating positive human-nature interactions.

It can be implemented at a range of scales, from individual homeowners to building developers and local and regional authorities.

BSUD aims to improve biodiversity in urban by design by utilising six steps (with step five being optional):

  1. identifying and mapping native species and ecosystems in the development area
  2. defining ecological objectives (such as maintaining or improving the viability of threatened species)
  3. defining development objectives (such as population and dwelling targets)
  4. identifying actions to achieve objectives, considering the “five principles of BSUD”, such as installing green roofs and walls
  5. quantifying the development’s contribution to biodiversity (for example, through population viability analysis)
  6. identifying the BSUD actions that best meet ecological objectives (Step 2), while also accommodating development objectives (Step 3) for the area

“You can’t offset nature”

Associate Professor Sarah Bekessy from RMIT’s Centre for Urban Research told The Fifth Estate why she helped develop the protocol: “Biodiversity should absolutely be incorporated into the bare minimum of planning rules.

“The urban fringe often hosts critically endangered ecosystems, such as Sydney’s Cumberland Plains Woodland, Perth’s Swan Coastal Plain, Melbourne’s Basalt Plains Grasslands, and they’re right in the path of where new housing is being developed.

“The problem is that the current approach in development is to offset the nature values that are lost – but you can’t offset nature the same way you can offset a carbon molecule – you can’t [successfully] recreate an ecosystem in its entirety. And you can’t offset the lost health benefits, and cognitive benefits, of having nature near you either.”

She noted that health is an important factor, as during Melbourne’s heatwave in 2009, more people died from heatstroke in Melbourne CBD than from fires. She added that this led the council to implement its urban forest strategy, which could help reduce the local temperature by four degrees.

Ms Bekessy also pointed to recent reports that have shown that tree cover can reduce asthma levels, that our immune systems as a whole are stronger and work better when we’re near nature, and that children who are exposed to biodiversity in their school grounds have substantially better cognitive development.

“All these benefits are being lost in urban development, and it’s such as waste. So, we’ve developed a protocol that is about designing cities in tune with nature, building new suburbs that actually completely integrate with the ecological foundations of the site, and creating an urban matrix that is positive to nature and not just the source of threats and decline.

“In doing that there could be massive advantages for Australia’s threatened species, and I believe create neighbourhoods that are much more attractive, resilient to climate change, healthier and safer.”

RMIT has developed some case studies of the BSUD in action, including one for Melbourne’s Fishermans Bend.

Currently expected to accommodate around 40,000 jobs and 80,000 residents, many development proposals include high-density, high-rise apartment towers situated on top of multi-level platform, with limited green space and little consideration of the Westgate Park, which provides habitat for “a significant number of native plant, bird, insect and amphibian species”.

RMIT identified that biodiversity would not only be affected by these developments, but that residents would also be “typically disconnected from nature and the streetscape below”.

The scientists therefore created a development that focused on biodiversity and well being utilising BSUD.

It highlights that need to protect the native species, especially birds, butterflies, frogs and micro-bats – and incorporate them into the built environment.

For example, semi-private courtyards within residential blocks could provide cooling and habitat for native species, including the Spotted Pardalote and Dainty Swallowtail butterfly, and ensure that residents are connected to nature. Incorporating habitat walls to buildings could also provide shelter for the flying species.

To improve human wellbeing and liveability, the team also incorporated “active streetscapes”, height limits for buildings of between four and seven storeys, and “high-quality and diverse” living spaces.

Associate Professor Mauro Baracco, deputy dean of landscape architecture and RMIT’s School of Architecture and Design, told The Fifth Estate that the idea would be to build an “urban filament”.

“Any new built environment should try to minimise the area that it is taking up, in order to leave much more area for open vegetated space. It would be better to stop designing in outer suburbs, because it would be better to work on infilling where there is already a built footprint, rather than creating more built footprints.

“But where development is already set to happen, you could create something with a low footprint. So we would build a new ‘filament city’ – a long, linear form that follows existing (or approved) infrastructure – like roads or railway lines – to limit impacts on the environment.

According to the team, the sustainable mid-rise “urban filament” model would “provide better urban design and human health and wellbeing outcomes, including better access to open space and improved streetscapes, a reduction in the urban heat island effect, a reduction in household energy use, and improved workplace productivity and childhood cognitive development”.

In addition, protecting wetlands required by some species could provide additional water purification and flood mitigation services, which is crucial as Fishermans Bend is flood prone.

More incentives needed from government and green rating systems

The two councils behind the development of Fishermans Bend and Victorian Planning Minister Richard Wynne are said to be “100 per cent behind the biodiversity redevelopment”, but Ms Bekessy said planning rules could act as obstacles for making it happen.

“We have some major planning obstacles to overcome,” she said. “One of them is that our planning system is so market-driven in Australia, and whilst I have no doubt that there would be a market for biodiverse cities, it’s under-explored – so can be held back as there’s little precedent.

“I think what is required is for someone from the government to provide some incentives or even some stronger regulation around the need to incorporate biodiversity into urban design [of] a new development. But then, we also need the Green Building Council and other groups to really start focusing on how green-rating schemes can incorporate impact on biodiversity [The GBCA’s Green Star ratings for Design & As Built does include an ‘ecological value’ credit when the building improves local environment, and a ‘sustainable sites’ credit that rewards building that remediates land].

“From one side we need to have regulation to encourage innovation and from the other side, we need to have the incentive through rating systems, so that good developers can be rewarded for implementing biodiversity in their plans.”

This article was published with permission from The Fifth Estate.

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