Tagged: biodiversity

Mayesbrook Climate Change Park

Restoration of the Mayes Brook in Mayesbrook Park, in the London Borough of Barking and Dagenham, was an opportunity to create an ecological and community focal point within a broader environmental regeneration project. It was designed to produce the UK’s first climate change adaptation public park. This restoration of an urban river within a barren park landscape is a good example of an approach that combines flood storage, biodiversity enhancement and adaptation to climate change within a city environment. This study explores some of the key benefits of the planned river restoration and the wider park ‘greenspace’ improvements, in terms of their impact on ecosystem services. The urban setting means that restoration and improvements contribute to ‘regulatory services’ (regulation of air and water quality, microclimate and flood risk) affecting the local community. Enhanced recreation and tourism (cultural services) are also likely to bring benefits, since many people in the borough lack gardens or ready access to other green spaces.


Robert Oates, Executive Director of the Thames River Restoration Trust introduces a field visit. Source: Ecosystems Knowledge Network

The benefits for ‘supporting services’, which are hard to quantify but important in maintaining ecosystem functions, are significant in terms of nutrient cycling and providing habitats for wildlife. This latter ensures there are animals and plants capable of colonising the wider landscape as the habitat improves. These improved habitats also serve as ‘stepping stones’ for wildlife to move across and between limited and fragmented suitable habitat in the urban landscape. Due to the urban setting and lack of biodiversity in Mayesbrook Park and the Mayes Brook, restoring the river does not boost ‘provisioning services’ (things that can be taken from ecosystems to support human needs, such as fresh water, food, fibre and fuel, and so forth). Many of the more important benefits of the Mayesbrook Park restoration can be seen in social and health aspects, enhancing the quality of life in the borough and the wellbeing of local communities.

In fact, if the annual value of services to health, risk and culture are pooled, despite there remaining many unmeasured or possibly unquantifiable benefits, they will account for over 90% of the total annual ecosystem service benefits for the Mayesbrook Park restoration scheme. The overall benefits are substantial relative to the investment. The lifetime value of restoring the site across the four ecosystem service categories (provisioning, regulatory, cultural and supporting) yields a grand total of calculated benefits of around £27 million, even if ‘likely significant positive benefits’ for the regulation of air quality and microclimate are excluded. This is compared to the estimated costs of the whole Mayesbrook Park restoration scheme at £3.8 million including the river restoration works. This produces an excellent lifetime benefit-to-cost ratio of £7 of benefits for every £1 invested. Urban river restoration would therefore be of major public value, fully justifying the planned investment and providing firm evidence that investment in urban ‘green infrastructure’ is highly favourable for the health and wellbeing of local people and the economic improvement of deprived wards. Restoring the vitality and function of the natural environment tends to enhance or maintain benefits across all ecosystem service categories. This contrasts with traditional single element solutions, which tend to maximise only the targeted services and often are associated with unintended consequences for other interconnected services. The case for the application of ecosystem-based solutions to environmental management problems is thus substantiated.

myersbrook2View of one of the lakes to be restored. Source: Thames Rivers Trust

The study sets out a range of options for further enhancing public value from
the restoration scheme, through new or redesigned initiatives or in management
practices. These include:

  • enhancing the hydrological function of the whole park landscape and infrastructure
  • using reed bed filtration to improve water quality in a bypassed reach of river and at lake inflows and outflows
  • improving climate regulation through energy-efficient building design, installation of renewable energy sources and reusing tree and other park trimmings as biomass fuel (or mulch) on site
  • optimising park restoration design to provide health and educational resources to the local community.

Assessing the ecosystem service implications for all of these options, and others that may be identified in later phases of planning and research, would help to support the economic case for their implementation. This case study provides evidence to help improve the current scheme design and the greater integration of social, economic and ecological benefits in future initiatives. The results of this assessment are valuable not only in the Mayesbrook Park restoration project but are also applicable to wider urban river and urban area restoration initiatives and will support future research in this field. It will also help in achieving ‘good ecological potential’ for the Seven Kings water body as part of the Water Framework Directive.

Restoration of the Mayes Brook – Executive summary – full text 

What is this initiative about? 

This project illustrates how an assessment on the services that nature provides for people helped in the regeneration of Mayesbrook Park.  The transformation allows the park to better serve the local community and also the city of London under a changing climate with increased flood risks.

The park is in the Borough of Barking and Dagenham, one of the twenty most deprived boroughs in the UK.  It was previously under-used and had few amenities, whilst the river was confined to a concrete channel and lay behind a metal fence, providing little value to wildlife or people.

How does it reflect the ecosystem approach? 

An assessment of the ecosystem services provided by the park both now and in the future identified its role in reducing flood risk, as well as its value for recreation and wildlife.  The assessment illustrated that £7 of benefits will be provided for every £1 invested in restoration of the park, which provided the basis for a funding partnership worth £1.6 million.

In valuing the ecosystem services, the project reflects the ecosystem approach, in that “Conservation of ecosystem structure and functioning, in order to maintain ecosystem services, should be a priority target of the ecosystem approach”.  The project also considers the long term effects of climate change and the associated risk of increased flooding and increased summer temperatures.  As such it reflects the ecosystem approach, which states “consider mitigating actions to cope with long-term changes such as climate change”.

Progress so far 

The first phase of the project includes re-routing the Mayes Brook along a more natural course, renewing the disused lakes and planting trees. The second phase includes the restoration of the two lakes, one for boating and one for angling, which will also improve habitat conditions for wildlife.  A visitor and facility centre will be built, along with a café and permanent exhibition on what the park is doing to adapt to climate change.

Challenges and lessons learned

The project highlights how an economic appraisal of the benefits that an area of land can provide for people, can bring about significant change.  The clear demonstration of the value of the project helped reassure and engage representatives of the local community.

It is also an example of partnership working, and of a scale of park regeneration that was only made possible by the combination of staff, funding and technical resources provided by the various partners involved.  It illustrates the potential for such a project to cause a resurgence of public interest in nature and access to the outdoors.  The involvement of the Environment Agency as a partner helped in the process of securing the numerous approvals needed (flood risk, contaminated land, soil disposal etc.).



An Alternative Garden Bridge for London?

“Get walkability right and so much of the rest will follow” — Jeff Speck, “Walkable City”, 2012

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Allies and Morrison’s proposal is based on reimagining the existing infrastructure  of James Cubitt’s 1869 designed Blackfriars Bridge by using spare capacity to accommodate a through public garden of similar size of the proposed Garden Bridge, while still providing the vital north-south link for vehicular and cycle traffic along the Blackfriars Rd – Farringdon Rd axis. The Allies and Morrison team state, “By consolidating both the east and west pavements into one larger 14m wide pavement on the west side, we could create a brilliant pedestrianised garden.”

This alternative design would still offer dramatic views of St Paul’s and the City to the east and Westminster to the west and offers a positive response to the Mayor for London’s recent publication Public London: Creating the best public realm – authored by Peter Murray, Fred Manson and Pam Alexander.  The Mayor’s ambitions for the creation of new public spaces and places in London are to, “bring public transport, walking and cycling together to create high quality public realm.”

Using the existing Blackfriars infrastructure connects the north and south shores of the Thames using existing infrastructure thus providing increased capacity in pedestrian access between The City to the north and Southwark and Elephant and Castle to the south whilst creating a green space for commuters plus additional green infrastructure capacity for London. The provision of additional pedestrian space also links with the latest ‘Cities Alive’ report, a collaboration between Arup’s Foresight + Research + Innovation, Transport Consulting and Urban Design teams.  The report ‘Cities Alive: Towards a walking world’ discusses the benefits of walkable cities – economic, social, environmental and political – and sets out measures for improving walkability.  “Creating safe and efficient transportation systems, liveable environments, a sense of place and community, and smart and responsive cities will all help to make walking a normal part of everyday life and the natural choice for shorter journeys.”

garden bridge2

This Blackfriars Bridge Garden concept celebrates existing infrastructure heritage just like New York’s Highline Parkway . Allies and Morrison claims that their proposal does not require extensive construction and can be delivered minus the initial cost of construction of a new bridge whilst connecting two areas of London where there is an existing need for additional commuter capacity. “It would provide 40,000 sq ft of new green space. It would remain public and accessible to all, seamlessly integrated into the existing public realm on both sides of the River without obstructing any of its views of St Paul’s. This light touch approach would be carbon neutral, and together with the cycle superhighway and solar panelled roof of Blackfriars Station, would be at the heart of a global exemplar for sustainable infrastructure.”

Source Text and images : www.alliesandmorrison.com. June 2016.


Research: Nature in urban environments reduces stress

“We believe that greater priority needs to be given to prevention of ill health in public health and social care. All those involved in creating healthy places – public health professionals, planners and landscape architects – need to recognise that landscape has enormous potential to improve our health and wellbeing.”

Landscape Institute.

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Source: Honold, J., Lakes, T., Beyer, R. & van der Meer, E. (2015). Restoration in Urban Spaces: Nature Views From Home, Greenways, and Public Parks. Environment and Behavior. 1-30. DOI: 10.1177/0013916514568556.

Urban nature — such as trees and public parks — is beneficial to human health. A number of studies have found that living close to nature can have immediate positive effects on mental and physical health. However, the longer term health impact of urban nature remains poorly understood. This study investigated how exposure to nature affects health in residents of two inner city neighbourhoods in Berlin. The researchers investigated the links between different kinds of urban nature, including green spaces and views of vegetation from the home, and health. To do this, they assessed life satisfaction, perceived general health and levels of cortisol — commonly known as the stress hormone — in hair samples from 32 participants.

Changed patterns of cortisol in the blood have been linked to depression and psychological stress. Over time, elevated levels of cortisol suppress the immune system and can therefore also contribute to other illness. The authors hypothesised that the amount and diversity of vegetation visible from the home would affect health. They also thought that more regular use of public green spaces could encourage better health.

They found that views of vegetation from the home (as assessed by photographs) and the use of green spaces (determined by interview) were linked to the amount of cortisol in participants’ hair. Participants’ hair cortisol levels were lowest when their view was of both a high vegetation quantity and diversity. No significant link was found between the view from the home and self-reported general health or life satisfaction.

When assessing the use of green spaces, the researchers found one of the most frequently visited areas to be a local canal with a highly vegetated trail. People who used this trail at least once a week had significantly lower cortisol levels than less frequent users and reported higher life satisfaction, although they did not differ in general health.

Overall, this study suggests that exposure to urban nature in different forms could be related to lower cortisol levels and better life satisfaction, which corresponds with findings made in other countries and continents.

These results provide important considerations for urban development and suggest that adding diverse vegetation to residential streets and backyards, and developing more urban greenways, has the potential to improve human health. The authors recommend that local authorities use this information when designing sustainable and healthy urban areas.

While the authors do note limitations to the study, including sample size, the methods used to analyse vegetation and the extent to which cortisol correlates with stress and health outcomes, their findings have been reinforced by other research. They also propose that hair cortisol analysis could provide a promising new health indicator for future research.

The Dalston Eastern Curve Garden in east London is a thriving community garden, developed on a small piece of derelict railway land by landscape architects J & L Gibbons, with muf art/architecture and Exyzt. The video shows some of the improvements in community health and wellbeing that the garden has brought, providing an oasis in the heart of a busy, noisy, high-density part of the city, where public green space is severely lacking.

This is the first in a series of Landscape Institute videos on landscape and health, featuring some of the landscape projects that illustrated the 2013 publication ‘Public health and landscape: creating healthy places’.

What does ‘Brexit’ mean for the environment?

‘People, Politics and the Planet: Any Questions?

6:00 p.m., 21 July 2016 at The Royal Geographical Society, 1 Kensington Gore, London, SW7 2AR.  


Join the Sibthorp Trust, the British Ecological Society and the Royal Geographical Society (with IBG) for the first post-referendum public debate on the future of environmental policy in the UK following the vote to leave the European Union, chaired by Jonathan Dimbleby.

Confirmed panellists include:

  • Baroness Kate Parminter, Liberal Democrats, Spokesperson for Environment and Rural Affairs
  • Natalie Bennett, Green Party, Leader
  • Kerry McCarthy MP, Labour
  • Stuart Agnew MEP, UKIP, Agriculture Spokesperson

Co-organised by the Sibthorp Trust, the British Ecological Society and the Royal Geographical Society (with IBG), with support from the Society for the Environment and the Wellcome Trust.

The UK has voted to leave the European Union, launching the country into a period of uncertainty as a new relationship with Europe and the world is negotiated. The EU frameworks that have underpinned much of our environmental policy and legislation – from agriculture to protected areas – are no longer assured.

Yet the challenges of climate change and biodiversity loss will lose none of their urgency. What will environmental policy in the UK look like outside of the European Union? What threats and opportunities does ‘Brexit’ pose for the environment? How will we tackle international challenges under a new political agreement?

The debate will be followed by a drinks reception, and the opportunity to view the Atkins CIWEM Environmental Photographer of the Year exhibition.

Book your ticket now at http://peoplepoliticsplanet.eventbrite.com. Tickets are available at £10 for BES/RGS-IBG members and concessions, or £20 full price.

Join the conversation on Twitter #PPPAnyQs, or watch last year’s debate

Public Park Funding: UK and USA Models

Our public parks in the UK are under increasing pressure, with limited resources available for maintenance and management. Public sector funding for discretionary services like parks is projected to fall by 60 per cent or more over the next decade.  New business models are needed along with management tools and partnerships to create a more sustainable future for the way our parks are used and maintained. Not only could this lead to greater financial security for parks, it could also create new opportunities for employment and education, increased health and well-being, and greater biodiversity.

rethinking parks

NESTA have produced a report ‘Rethinking Parks’ by Peter Neal which highlights the need for new business models to run parks, given the cuts in government funding, and discusses 20 international examples of how parks innovators are doing just that.  The report highlights that there will be challenges in developing and adapting new business models for parks. This includes ensuring public parks are integral to, and reflective of the surrounding cultural, socio-economic and physical context. In some contexts private management models for public parks may offer a sustainable financial model, while in other areas cooperative management with local communities may be a more viable option.

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London Councils, which represents 32 boroughs and the City of London, said budget cuts had put local services, such as social care, under pressure.  It warned funding for community groups and volunteers who maintain the parks is under threat, as they prioritise other services, such as looking after homeless people.  If the cuts continue, councils may be unable to stop the parks being sold off and run privately by 2025, it warned.  Councillor Julian Bell, chair of London Councils’ Transport and Environment Committee, said: “We have got to do everything we can to protect our parks for our future generation.”

The Challenges of Providing Public Space with Private Funds by Liz Camuti| The Dirt | 06/10/2015 

The following article was published in The Dirt published by the American Society Of Landscape Architects.

“In an age of ample private wealth and an increasingly constrained public sector, a number of American cities have become dependent on privately funded conservancies to maintain and refurbish their public parks. A new report by Peter Harnik, Hon. ASLA, and Abby Martin from The Trust for Public Land’s Center for City Park Excellence explores the rise of such city park conservancies — private organizations that use donations to rebuild, renovate, and, in some cases, maintain some of the most iconic parks in the country. Interspersed with examples from 41 conservancy organizations that have a collective experience record of nearly 750 years, the study serves as a how-to guide for building successful relationships between city governments and urban park conservancies.

While many park-support organizations exist throughout the country, including friends-of-parks groups and business improvement districts, the study defines a conservancy as a “private, nonprofit park-benefit organization that raises money independent of the city and spends it under a plan of action mutually agreed upon by the government.” Throughout the study, Harnik and Martin maintain that the key to this relationship is that the land remains the city’s and the city retains ultimate authority over everything that happens there.

New York’s Central Park Conservancy, which was founded in 1980, is generally considered the catalyst for the conservancy movement. Following a nationwide recession in the 1970s which severely damaged NYC’s already declining parks department, NYC Mayor Ed Koch and parks commissioner Gordon Davis appointed Betsy Barlow Rogers as Central Park Administrator. Rogers created a revolutionary public-private partnership that would bring private money and expertise together with the City of New York to restore Central Park. The study contends that to this day, New York has used conservancies more so than any other city and continues to provide lessons for other public-private partnerships.

Since the formation of the Central Park Conservancy, urban park conservancies have become a favored tool for revitalizing many parks across the country (about 50 percent of major cities have at least one). However, the strength of the study is that is does not gloss over the inevitable conflicts that arise when trying to build a successful public-private relationship, nor does it consider conservancy support as the panacea for urban park management. As was the case with the Central Park Conservancy, most conservancies are founded to restore dilapidated historic parks and address shortcomings in governmental funding. Yet, this can often create an ideological conflict.

For every person that is skeptical of government, there is another who is skeptical of increasing private control over public space. While many city governments often lose the capacity to maintain a park’s programs and amenities without private support, putting too much responsibility in the hands of a conservancy can lead community members to suspect a park is becoming completely privatized. For example, civil right attorney Larry Krasner, who defended a group of Occupy Wall Street protestors, states, “I think there is a trend of analogizing public space to shopping malls. I think a lot of people view that as a sad state of affairs. It seems to indicate that government is insufficiently funded or not able to provide services we used to take for granted.” The study is upfront and honest about the challenges these conflicting mentalities can create for restoring, maintaining, and improving urban parks.

Among these challenges, there are two that conservancy-supported parks appear to face time and again: Maintenance and safety. According to the study, finding the money to cover basic maintenance costs can be a challenge – often the challenge – for conservancies and city governments alike. While big capital projects are more flashy and attract private donations, maintenance is less sexy. For this, Harnik and Martin offer one thoughtful solution inspired by the Central Park Conservancy: Have conservancies build in “a long-term maintenance fee to the initial budget of each capital project – an upfront gift that becomes a permanent trust fund.” Such a solution ensures that the maintenance of donor-attracting capital projects does not fall solely on the city government’s shoulders.

The issue of maintaining public safety is slightly more complicated. The study provides several examples, including Piedmont Park in Atlanta and Civic Center Park in Denver, where public-private arrangements have gone awry in the wake of public safety concerns that discourage donors and visitors. While the Civic Center Conservancy stepped up programming and the Mayor of Denver allocated more money for policing and security after a 2013 shooting, specific suggestions for dealing with urban crime and public safety generally fall outside the scope of the study.

Though the conservancy-based approach to urban park management is still emerging, the study could have benefited from more examples of conservancies that were formed hand-in-hand with brand new green spaces. Of course, private organizations that are formed in response to governmental shortcomings will face unique challenges and conflicts, but what if these relationships were established at a park’s inception? The study cites this approach as a growing trend but gives few examples to support or deny its success.

Ultimately, the report serves as a comprehensive guide for philanthropists and mayors, as well as bureaucrats and board members, who wish to create and maintain successful partnerships that benefit our urban green spaces. For the rest of us, the study provides a reminder that the free parks we often take for granted are hardly free.”

Read the full report and also check out Trust for Public Land’s new City Park Facts 2015, which has tons of data on the top 100 park systems in the country.

Nature, biodiversity, ecosystem services and well-being

              A recent paper by Sandifer et al (2015) explores the opportunities to enhance health and biodiversity conservation.

“Exploring connections among nature, biodiversity, ecosystem services, and human health and well-being: Opportunities to enhance health and biodiversity conservation” 


  • Evidence links biodiversity to ecosystem services (ES) and health to nature exposure.
  • A few novel studies link biodiversity exposure to improved health and well-being.
  • We provide a comprehensive summary of health effects of ES, nature and biodiversity.
  • Future research should address causation of health benefits and action mechanisms.
  • New multidisciplinary collaborations are needed to enhance health and conservation.


We are at a key juncture in history where biodiversity loss is occurring daily and accelerating in the face of population growth, climate change, and rampant development. Simultaneously, we are just beginning to appreciate the wealth of human health benefits that stem from experiencing nature and biodiversity. Here we assessed the state of knowledge on relationships between human health and nature and biodiversity, and prepared a comprehensive listing of reported health effects. We found strong evidence linking biodiversity with production of ecosystem services and between nature exposure and human health, but many of these studies were limited in rigor and often only correlative. Much less information is available to link biodiversity and health. However, some robust studies indicate that exposure to microbial biodiversity can improve health, specifically in reducing certain allergic and respiratory diseases. Overall, much more research is needed on mechanisms of causation. Also needed are a re-envisioning of land-use planning that places human well-being at the center and a new coalition of ecologists, health and social scientists and planners to conduct research and develop policies that promote human interaction with nature and biodiversity. Improvements in these areas should enhance human health and ecosystem, community, as well as human resilience.

healthy Places2


Human health and well-being can be considered the ultimate or cumulative ecosystem service (Sandifer and Sutton-Grier, 2014). For medical practitioners and the public, health often is thought of narrowly as the absence of disease. However, the World Health Organization (WHO, 1946) defines health much more broadly as “…a state of physical, mental and social well-being and not merely the absence of disease or infirmity.” Health, or health and well-being, are also described as including a supportive environment, personal security, freedom of choice, social relationships, adequate employment and income, access to educational resources, and cultural identity (Diaz et al., 2006 and MA (Millennium Assessment), 2005). Here we use these latter definitions to encompass the breadth of factors that together comprise human health and well-being.

Just as we are beginning to appreciate the variety and complexity of human health benefits that stem from experiencing nature and, more specifically, biodiversity, we are reaching a critical point in human history where biodiversity and habitat losses are accelerating due to increased human use, climate change, and rampant development. Strengthening the focus of nascent science efforts in this area on a much deeper understanding of nature–biodiversity–ecosystem service–health linkages could play a critical role in supporting growing policy efforts to incorporate more natural areas and biodiversity in the design and protection of our cities and coastal communities, with concomitant public health benefits.

In this paper, we explore observed and potential connections among nature, biodiversity, ecosystem services and human health and well-being, through biodiversity–ecosystem services linkages, associations of nature with human health, and recent limited evidence relating biodiversity to some human health outcomes based on a review of selected literature. We used the generally accepted definition of nature as the physical and biological world not manufactured or developed by people. We were interested in the health effects of human exposure to natural elements such as plants and other living things, natural areas including coastlines and mountains, natural and semi-natural environments such as parks and managed forests and wildlife sanctuaries, and undeveloped landscapes, seascapes and, in some cases, even agricultural lands. Biodiversity was also defined broadly. Based on language from the Convention on Biological Diversity (United Nations, 1992), Duffy et al. (2013) described biodiversity as “the variety of life, encompassing variation at all levels, from the genes within a species to biologically created habitat within ecosystems.” Nature is not biodiversity, nor a proxy for biodiversity, but certainly encompasses biodiversity. Ecosystem services are the specific benefits people derive from nature (MA (Millennium Assessment), 2005).

We concentrated on reported and potential values of exposure to natural elements, ecosystem services, and biodiversity, to human health and well-being. In general, we noted a lack of studies that identifiedcausality and specific mechanisms by which either nature (often meaning green space, particularly urban green space) or biodiversity supports ecological functioning and hence, the provisioning of all ecosystem services and human health and well-being ( Cardinale et al., 2012). Thus, with one major exception discussed here, the actual roles of biodiversity in promoting human health and well-being remain largely uncertain. We addressed the following questions: (1) How important is biodiversity to the provision of ecosystem services? (2) Is there convincing evidence that experiencing more natural settings, even briefly or vicariously, can improve psychological and physical health? (3) Does exposure to biodiverse surroundings result in measurable health responses? (4) Can biodiversity provide humans and animals protection from infectious and/or allergic and inflammatory diseases? (5) Is there evidence that experiencing coastal nature or marine biodiversity has health effects? Based on our findings, we suggest that new research and policy strategies, involving collaboration among ecological, environmental health, biomedical, and conservation scientists as well as urban, land and coastal planners, and social scientists, are needed to make critical progress toward answering these and related questions. We conclude with ideas for key components of those strategies and recommendations for a way forward.

healthy Places

The Landscape Institute published their ‘Public Health and Landscape: Creating healthy places‘ Position Statement which introduces five principles of healthy places.

  • Healthy places improve air, water and soil quality, incorporating measures that help us adapt to, and where possible mitigate, climate change
  • Healthy places help overcome health inequalities and can promote healthy lifestyles
  • Healthy places make people feel comfortable and at ease, increasing social interaction and reducing anti-social behaviour, isolation and stress
  • Healthy places optimise opportunities for working, learning and development
  • Healthy places are restorative, uplifting and healing for both physical and mental health conditions

Can rooftop gardens grow city’s vegetables?

2014-08-20 11.06.46 Rooftop gardens in cities could provide more than three quarters of the vegetables consumed in them, a case study from Bologna, Italy, suggests. If all suitable flat roof space was used for urban agriculture, rooftop gardens in the city could supply around 12 500 tons of vegetables a year whilst also providing a range of ecosystem services, the researchers say.  

Source: Orsini, F., Gasperi, D., Marchetti, L., et al. (2014). Exploring the production capacity of rooftop gardens (RTGs) in urban agriculture: the potential impact on food and nutrition security, biodiversity and other ecosystem services in the city of Bologna. Food Security 6(6): 781-792. DOI: 10.1007/s12571-014-0389-6.

Any unused roof space in a city represents an opportunity to add to that city’s green infrastructure. Urban green spaces and infrastructure, which include rooftop gardens, offer benefits for both wildlife and people. Not only can they produce food for city-dwellers, they can increase urban biodiversity and link together to form green networks, acting as corridors for wildlife. They can also reduce a city’s ecological footprint by filtering polluted air, absorbing noise and CO2 emissions, and controlling temperature by shading.

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In 2010, Bologna became the first Italian city to test rooftop vegetable gardens on public buildings, as part of a project led by the local authority, university and a non-profit organisation. Researchers followed the trial over three years between 2012 and 2014.

During this time, rooftop gardeners grew lettuce, black cabbage, chicory, tomato, aubergine, chili pepper, melon and watermelon, either in plastic pipes, recycled pallets filled with compost or on polystyrene panels floating in tanks, also made from recycled pallets.

On average, the recycled pallet system with compost produced the most vegetables for the amount of space used, a third more than the floating system and more than twice that of the pipe system. However, the amount of each type of vegetable produced by each system in each season varied considerably and the pipe system made use of hanging space when surface area was limited.

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From the results of the trials, the researchers were able to design an optimal growing system for a 216 m2 rooftop garden, which combined elements of each system in order to maximise productivity throughout the year. This included slightly more floating structures than pallets, as well as pipe systems along the railings. The researchers estimate that this hypothetical garden could produce more than three tonnes of vegetables per year.

Next, the researchers estimated the potential productivity of a network of vegetable gardens occupying all suitable flat roof space across the city. They used digital maps and computer-aided design (CAD) software to identify all the unused flat spaces on Bologna’s roofs and terraces.

Their calculations suggest that, if all available space (about 0.82 km2) was utilised, rooftop gardens in Bologna could produce around 12,500 tonnes of vegetables. This means that, based on actual consumption data for the city, rooftop gardens could meet 77% of residents’ needs for vegetables.

If all the spaces identified in the study were turned into gardens, they could capture an estimated 624 tons of CO2 each year. The study’s authors also mapped the connections between spaces that were within 500 m of each other showing that rooftop gardens could create a network with a total length of 94 km of green corridors for wildlife, including pollinating insects. The 500 m distance was considered appropriate by the researchers because most common bee pollinators have a flight foraging distance of 750–1500 m.

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Images above are of the London’s Southbank Centre roof garden, created as a partnership between Southbank Centre and the Eden Project, it was built from scratch by the Grounded gardening team from Providence Row Housing Association (PRHA) working with colleagues from Eden.  Unusual foods such as blue potatoes, narga peppers as well as a mini olive grove are being grown. They also aim to add more greenery to Southbank Centre, training vines, hops and ivy over the concrete walls. Raised beds, wild and pollinating flowers and the lawn will also be maintained.

Images: Carine Brannan