Green Roofs for Biodiversity: Protecting Birmingham's Wildlife

Posted on Friday 20th October 2006

Researchers at the University of Birmingham's School of Geography, Earth and Environmental Sciences are using the latest habitat replication techniques to protect Birmingham's wildlife. A project is underway to build green roofs which mimic the brownfield habitats often destroyed during the development process.

Brownfield sites are post-industrial sites which are often developed to provide housing, retail or office space. The project aim is to provide high-quality habitat using recycled materials to help conserve many rare species associated with urban brownfield sites including bumble-bees, butterflies, beetles and birds. One bird in particular, the black redstart, whose numbers are declining due to increased development, has a long historical association with brownfield sites in Birmingham and is one of the UK's rarest bird species. By installing green roofs in locations where black redstarts are known to exist, a network of foraging habitat will be created in the city centre, which it is hoped the black redstarts will start to use when their existing brownfield sites are developed.

The researchers are recommending how the green roofs should be designed to maximise the benefits for local wildlife. This includes advice on which wild flowers to sow and what type of growing medium should be used. The growing medium will mimic conditions found on brownfield sites and will be a mixture of reclaimed brick, concrete and soil. Using reclaimed materials enhances the sustainability of the scheme as the rubble from demolition sites no longer needs to be sent to landfill.

The quantity of rainfall runoff will also be measured to get a better understanding of how green roofs can be used to alleviate urban flooding. The quantity and rate of rainfall draining from a green roof will be less than that draining from a conventional flat roof as the rain is used by plants, evaporates or drains away over a longer period of time, reducing the intensity of storms and therefore reducing local flooding problems.

Dr Rossa Donovan, from the School of Geography, Earth and Environmental Sciences, says, 'This project is one element of the research that Dr Jon Sadler and I have been working on for the last 7 years. Our research, which focuses on many aspects of urban ecology has shown that post-industrial sites sometimes called brownfield or wasteland sites, are very important ecological habitats within the urban setting. Government policy recommends that these post-industrial sites are developed to maximise land use and prevent urban sprawl. The landscaped areas that replace them following development do not equate to the habitat lost due to development. Using green roofs to mimic habitats usually found on brownfield sites is one solution and will help the development process to become more sustainable'.

Following installation of the green roofs, there will be a three-year programme of ecological and hydrological monitoring to evaluate the effectiveness of these replica habitats. The roof of the ICC will be the first roof to be 'greened' and other green roofs at the Birmingham Voluntary Service Council building and the Islamic Relief headquarters at Trafalgar house will be created.

The roofs have been made possible by funding of £175,000 from the SITA Trust.

Ends

 Notes to Editors

The work on rainfall runoff links with an EU funded project investigating the ecological and hydrological performance of different green roof substrates led by Professor Ray Mackay, who is working with Dr Adam Bates and Dr Richard Greswell who are all researchers at the School of Geography, Earth and Environmental Sciences at the University of Birmingham.

Partners on this project are: Groundwork Birmingham and Solihull, SITA Trust, Environment Agency, Birmingham Environmental Partnership, Advantage West Midlands, Birmingham and Black Country Wildlife Trust, Birmingham and Black Country Biodiversity Partnership, BVSC - The Centre for Voluntary Action, The ICC, Islamic Relief, Land Care Associates, Living Roofs, Birmingham City Council

For further information

Kate Chapple, Press Office, University of Birmingham, tel 07789 921164.