What kind of wildlife flourishes in cities?

The High Line in New York City, a former elevated railroad trestle converted to a public park. Image: Shinya Suzuki/Flickr/creative commons.

Biodiversity refers to the variety of all living things on Earth, but people often have very specific ideas of what it means. If you run an online search for images of biodiversity, you are likely to find lots of photos of tropical rainforests and coral reefs.

Those ecosystems are invaluable, but biodiversity also exists in many other places. More than half of the people on Earth live in cities, and that number is growing, so it is especially important to understand how biodiversity patterns occur in our man-made environments.

As an ecologist specializing in urban systems, I spend a lot of time investigating biodiversity in parks, residential areas and abandoned zones in and around the city of Baltimore. My main interests are seeing how urban dwellers invest in biodiversity, which species persist in cities and what kinds of biodiversity can thrive in green spaces.

In spite of the substantial environmental changes that humans have caused in cities, research shows that they still contain many forms of life. And we can develop and maintain habitat to support them.

Human impacts

Human activities such as farming and building roads disturb the environment. This changes habitats, causes plants and animals to move and alters biodiversity patterns.

In cities many of these shifts are obvious. Cats and coyotes are now the top predators in many urban areas, perhaps replacing species that dominated before these areas were settled. Humans have introduced exotic species such as tree of heaven, and pests such as the emerald ash borer. And our living patterns have promoted eruptive growth of some species, such as white-tailed deer.

Razing a vacant row home in Baltimore, Maryland. This kind of activity creates habitat. Image: author provided.

It is common to assume that few other species remain in disturbed urban environments. But in fact, there are many pockets of biodiversity in and around cities, such as frogs living in stormwater detention ponds and trees in restored streamside forests. Landscapes that people create in and around their homes support many ornamental herbaceous and woody plant species.

Our research group works to understand the relationship between people and urban biodiversity patterns. The most prominent feature of the urban environment is that it is fragmented into many small zones. Human activity creates more patches of smaller size and greater edge lengths between types of habitats than we would expect to see in undisturbed areas.

This benefits species that thrive at edges, like white-tailed deer and nuisance vines, but harms others that require larger interior habitats, such as certain birds. As human activities create a more fragmented environment, it becomes increasingly important to create linkages between natural areas, such as preserved forests, to maintain populations and their biodiversity.

Humans also modify dispersal patterns. We place preferred plants in our yards and gardens, transplant wild shrubs from forests to suburban yards and trap nuisance animals such as beavers and relocate them to forests.

Two vacant lots where row homes once stood in Baltimore, Maryland. Each plot was cleared and seeded with native species. Even after one year on these poor soils, native plants established. Image: author provided.

Work from our research group has successfully related people’s management practices to understand how species are gained or lost from one location to the next. This concept, which we call “species turnover,” is a major way in which biodiversity increases in cities. Where people make many different types of choices, we have found that the trees people manage change a lot. This tells us that what one person sees as valuable differs from the views of another, which increase biodiversity in these areas. In “ignored” or less managed areas, such as vacant land, we see a less diverse mix of species on average.


How past actions influence the present

Ecologists can also understand biodiversity in cities by studying how humans have altered and then abandoned some areas, and how plants and animals have responded. Such human legacies are profound in old cities like Baltimore.

Our research group has studied these impacts on patches of land where buildings once stood. There are more than 14,000 vacant lots in Baltimore where houses have been razed, which adds up to a lot of habitat.

We have found that buildings’ footprints have very different soils from the areas around them that once were backyards. Footprint soils are compact and comprise mainly building rubble, while backyards have healthier soils. Although these habitats are close together, they support different plant communities. Plants growing on building footprints tend to be similar, while there is very high species turnover in former back yards.

Helping urban ecosystems thrive

Every species has traits, such as a plant’s nitrogen fixation rate and flower color. These characteristics support the services that the species can offer – for example, providing habitat for songbirds. As cities move toward more green practices, knowing about species’ traits can help planners choose which plants, animals, birds and insects to support.

In West Baltimore, my research group has cleared and seeded vacant lots with different mixes of native plants that reflect different traits to learn which species combinations can confer the most ecosystem services. In urban areas, valuable ecosystem services include supporting bees and other pollinators and improving soil quality.

We have found that native plant species can become established and persist even on poor urban soils. Working with local high school students, we have carried out pollinator surveys over two years, which show that these plants support more abundant and more diverse communities of pollinators, including bumblebees and butterflies. Over the next five to 10 years, we plan to expand this work across 65 plots on vacant land so that we can understand the full range of ecosystem services that native plants provide.

7x7 meter experimental plots where 15 abandoned row houses once stood. These plots are being seeded with different mixes of native plants. Image: author provided.

Residents who live near our research plots are happy to see areas that were unmanaged and largely neglected turn green. Even small “pocket parks” can brighten communities.

The ConversationWe have many other questions about urban biodiversity. How do city dwellers living in cities think about biodiversity? What traits of different animals and plants do people find attractive, and do those traits provide desirable ecosystem services? By analysing these issues, we can learn more about which animals and plants do the most to enhance city life and how we can help them thrive here.

Christopher Swan is professor of geography and environmental systems at University of Maryland, Baltimore County.

This article was originally published on The Conversation. Read the original article.

 
 
 
 

Here are my five favourite London council estates

The Dunboyne Road estate. Image: Steve Cadman/Wikimedia Commons.

The author is a Labour member of the London Assembly. In the name of impartiality, CityMetric would like to extend the invitation to write similar columns to representatives of other political parties.

From successful post-war efforts to move families out of slums and into modern homes, to today’s efforts to construct a new generation of social housing, there’s much to be celebrated in London’s precious council housing stock.

This year we celebrate the centenary of the Addison Act, which established a national building programme with government funding for the first time. So here – in no particular order – are my top five London estates:

1. Dunboyne Road

In 1965, the newly established London Borough of Camden was bold and radical when it came to public housing. Their architect’s department boasted 98 staff, led by Sydney Cook. The Grade II listed Dunboyne Road (pictured above) was Britain’s first high-density, low-rise estate. Designed in the late 1960s and completed in 1977, it was the first major work by architect Neave Brown.

Its concrete construction and geometric layout are eye-catchingly modernist, but the 71 flats and maisonettes fit neatly into their surroundings; a reimagining of the classic London street for the 1960s. Each has a private terrace and own entrance onto the central pedestrian walkway and communal gardens, with stepped levels and dual-aspect windows creating light throughout.

Neave Brown himself lived on the estate in the final years of his life remarking, “Who am I to say, but it’s beautiful”.

2. Lilington Gardens

Located just off Vauxhall Bridge Road, the fourteen blocks at Lilington Gardens were built between 1964 and 1972. Between three and eight storeys each, it was again a rejection of the tower blocks which dominated the era, showing that mid-rise housing could provide both beauty and density.

Image: Ewan Munro/Wikimedia Commons.

At a time when Westminster could be proud of the quality of its housing, John Darbourne and Geoffrey Darke won a competition to design the new estate. The result was something special, eschewing modernist forms for something more rugged and layered. The layout allows for secluded green spaces, while the red brick cladding echoes the neighbouring Victorian church of St James the Less. Like all good estates, it included a pub – the Grade II*-listed Pimlico Tram (now The Cask). It was included not as an afterthought, but an integral part of the estate’s design.

3. Ossulston Estate

By the early 1950s, the London County Council’s architect’s department was the biggest in the world, building housing on a huge scale in addition to showp iece projects such as the Southbank Centre.

Though their suburban estates – Downham in Bromley, and Becontree in Barking and Dagenham – were pioneering examples of low-rise of modernity in metroland, these efforts did not always suit the needs of poor city dwellers who weren’t able to move further out. The Ossulton Estate, however, built between 1927 and 1931 on the site of a Somerstown slum and located between Euston and St Pancras stations, did exactly that.

Image: Stephen McKay/Wikimedia Commons.

Chief architect George Topham Forrest’s work was inspired by visits to ‘Red’ Vienna and Ossulston bears distinct similarities to Karl Marx-Hof, which was constructed at the same time. While the roofs and windows have traditional elements, the overall aesthetic is a modernist classic. Like many estates in post-war years, it suffered from neglect and a lack of investment, but following a £6m improvement programme by Camden Council in 2004, the Ossulston is now back to its brilliant best.

4. Alton Estate

Roehampton’s Alton Estate, completed in 1959, was designed by a team led by Rosemary Stjernstedt – the first woman to serve as a senior public sector architect in Britain.

The two parts of the estate – East and West – are the crown jewels of British post-war council housing. Alton West was Le Corbusier in Albion: six ultra-modernist blocks modelled on the Unité d’habitation in Marseille, set among the landscape inherited from the Georgian Mount Clare house. Alton East was a softer, Scandinavian-inspired design of the “new Brutalists” in the LCC.

Image: Stevekeiretsu/Wikimedia Commons.

Rising above the trees to the north east of Richmond Park, the Alton Estate stands testament to the visionary idealism of post-war council housebuilding. On its completion, visitors flocked from across the globe, with American critic G.E. Kidder Smith calling it “probably the finest low-cost housing development in the world”.

Sadly, Alton West however is now at risk from ‘regeneration’ proposals which would see 288 existing homes lost. While council estates should not be fetishised, with investment, improvement and expansion encouraged, any change must be done sensitively and with residents’ backing. I hope that Wandsworth Council and Redrow will follow the mayor’s Good Practice for Estate Regeneration and hold a ballot before plans go ahead, and that if they do, they build on Rosemary Stjernstedt’s legacy.

5. King’s Crescent

When it comes to regeneration Hackney Council have taken an altogether different approach to Wandsworth.

Located on Green Lanes opposite the magnificent Clissold Park, King’s Crescent’s route to a successful and well-supported regeneration project hasn’t always been an easy one. The early 1970s estate was blighted by poor construction, navigability issues and an ill-fated partial demolition in 2000 which turned much of the landscape into hoardings and rubble. But thanks to a step-change in resident engagement and a transformation programme funded by Hackney Council, by 2023 it will be host to 765 new and refurbished homes.

Image: David Holt/Wikimedia Commons.

In the era of government-imposed cuts to local authority budgets, councils have to be pragmatic about funding choices and the new King’s Crescent does include homes for private sale. This is understandably a source of some consternation, but it’s also the source of funding which has made the regeneration possible. Hackney has ensured that more than 50 per cent of the new homes are genuinely affordable, with 97 brand new council homes for social rent.

The new developments have greatly enhanced the area, using both new build and renovation to stitch the estate better into its Victorian surroundings. Existing homes have been retrofitted with balconies, while disused garage space has been repurposed for modern flats. Hackney have clearly thought carefully about character and open spaces, as well as ceiling heights, windows and internal storage.

It is an exceptional project – one of a growing number of new schemes now being spearheaded by ambitious councils across the capital. In 2018-19, the Mayor of London funded the start of 1,916 new council homes – the highest figure since 1984-85.


…what about the Barbican?

On the fiftieth anniversary of its opening, it would be remiss not the mention the Barbican. It’s a brutalist masterpiece and a fantastic feat of post-war planning and design. The location and design are clearly outstanding, but it’s the bright and modern interiors which are truly to die for.

So why is it not on the list? Although it was built by the City of London Corporation, not one of the flats was ever available at a social rent. The properties were built to let at market rents to workers in the City, who later found themselves in the fortunate position of being able to snap them up under the Right to Buy – still the fate of far too many of London’s vital social homes.

Tom Copley is a Labour member of the London Assembly.