- How much should we worry about exotic species in urban zones? How do we reduce damage from exotic invasives when management resources are limited? Are there conflicts between management or eradication efforts and building general support for urban biodiversity?
Pippin Anderson, Cape Town
David Burg, New York
Mark Davis, St. Paul
Ana Faggi, Buenos Aires
Katie Holzer, Davis
Madhusudan Katti, Fresno
Deborah Lev, Portland
Timon McPhearson, New York
Matt Palmer, New York
Toby Query, Portland
Glenn Stewart, Christchurch
Paula Villagra & Carmen Silva, Los Rios
Peter Werner, Darmstadt
August 20, 2014
In terms of physical implementation, we have an endless stream of good knowledge, theory, and practice for building sustainable, nature-inclusive cities; a collection reaching back for well over a century.
What’s missing, I would argue, are not methods and knowledge, but a consciousness of our relationship to the environment, one which supports a consistently growing integration of nature into our urban agenda.
With this consciousness would come the ultimately necessary understanding of how culture and nature fit together to form the basis of an ecologically connected society. This is not an understanding ecologists alone should hold; it is one which on some level or another, all citizens need to carry with themselves in order for any serious attempt at inserting ‘nature’ into a city can truly be considered successful. This consciousness would essentially flip our common mantra of “how does nature fit into the city” into a “how does city fit into and with nature” way of thinking.
I am not an urban planner, academic, or landscape architect; but rather an artist who likes to work with these types of folks. My work straddles rural and urban in attempts to find ways of temporarily unplugging people from their world of economic and political logic, and expanding their consciousness of the reality of the local, regional, and global natural systems which support them.
With this in mind, I would like to use a recent experience of leading a social / ecological art project on Megijima, a small Japanese island with just 130 inhabitants, to ask: what can we learn about urban nature from the loss of traditional culture?
The following writing includes a rather informal dissemination of the ecological and social transformations on this small island, and related suggestions as to how the understanding of such transformations could help us look differently at how nature might … Continue Reading
The Story of Jerusalem’s Railway Park: Getting the City Back on Track, Economically, Environmentally and Socially
August 18, 2014
Sharing local experience is always important. However in the case of the Jerusalem Railway Park, both the process and the outcome have the level of universal relevance that make so many of the themes presented in “The Nature of Cities” essential urban reading.
I refer to themes of the kind that not only have immense impact on a specific local environment, but also fit into the wider context of sustainable urban planning. Indeed, the real challenge of sustainable urban development does not lie in the planning and building of new green neighborhoods, where everything is tidy and organized from square one, but in regenerating abandoned infrastructure in built neighborhoods, taking into account the needs of housing clusters that will be ever denser. Furthermore, the very same new green neighborhoods that claim to be exemplary models of sustainability tend to create new suburbs, requiring additional energy, water, sewage and transport infrastructure. Only too often new suburbs generate a sense of alienation from the pulse of urban life, while playing a role in polluting the city’s inner neighborhoods with the stream of traffic they pour into the city center.
One of the major challenges for modern cities is the need to adapt old infrastructure to modern needs. This is true of many different kinds of infrastructure, such as abandoned quarries, or industrial areas no longer relevant to the city, both of which are examples of the kind of urban challenge created by infrastructure that is no longer needed. Abandoned railway tracks rank high in this category, but in the last decade or so urban planners have risen to the challenge and turned many such abandoned lines into green corridor parks, which enhance, rather than impede urban improvement.
The case of Jerusalem’s Railway Park is particularly interesting, because of the measurable evidence we have of the … Continue Reading
August 12, 2014
The swifts have gone. They left about a week ago and the sky is silent over British towns and cities. By now they will be well on their way south, quartering marshes in the south of France and Spain, making for Gibraltar where they cross to Africa; airborne now until they return next May.
They are not with us for long, but for many people the screaming flocks around the rooftops are the very essence of summer. They are as much a part of urban life as we are, for these birds are totally dependent on buildings for their nest sites. Some colonies in older towns and cities depend on individual buildings, or old walls, which have been occupied for many years. The Wailing Wall in Jerusalem is thought to be the oldest known site of a colony. Ancient city walls of Siena in Italy have supported colonies of swifts for several hundred years. This is typical of many European towns dating from the medieval period with old buildings and town walls still supporting substantial colonies within the urban fabric. Roof spaces of imposing 19th Century buildings such as museums and City Halls, along with housing of the same period, are also favoured nesting locations.
The colony of swifts that occupies the roof of the University Museum of Science in Oxford provided the basis for one of the most extraordinary ornithological studies, described by David Lack in his book Swifts in a Tower in 1956. He and his wife Elizabeth produced a detailed account of the life history and ecology of swifts that is a model in the literature of urban ecology.
Although we know a great deal about the intricacies of their lifestyle it has been difficult to make accurate estimates of their population both nationally and locally. During the … Continue Reading
August 6, 2014
Collectively, researchers over the past 60 years (or more) have collected a good deal of data on urban biodiversity and impacts on urban plants and animals. From urban gradient studies to patch dynamic studies, we have a plethora of empirical data that suggests how various urban designs would impact various species. However, these studies have not affected actual planning decisions in most cities (there are exceptions of course).
Often, to address biodiversity, urban decision makers do not use empirical studies because they are too detailed and/or they target particular taxa (i.e., urban bird studies dominate the scientific literature). Most planners and other urban decision makers rely on broad ecological theories to shape planning.
Planners can manipulate three things that affect urban biodiversity: 1) the quality, amount, and patch size of conserved open space; 2) how open space and nearby built areas are managed; and 3) the degree of open space connectivity. Currently, to guide green infrastructure conservation, planners and landscape architects use island biogeography theory (MacArthur and Wilson 1967), using species-area curves and distance to source calculations, which translates into conserving large remnant patches (Linehan et al. 1995). They also create wildlife corridors and improve landscape connectivity, which stems from meta-population theory (Keymer et al. 2000). Overall, these ecological theories translate into clustering built areas, conserving some percentage of open space, and protecting lands for corridors (Arendt 1996). While conserving some connected patches is a good step, in reality, it is much more complicated to determine which species gain and/or lose from one design versus another.
In reality, suites of flora and fauna respond differently to sizes of connected patches, nearby land use impacts, and fragmentation/edge effects. A given corridor and patch arrangement has different effects on mammals, butterflies, herpetofauna, birds and the associated vegetation community. For example, scattered patches of … Continue Reading
August 2, 2014
(This encore publication originally appeared at TNOC on 7 August 2012.)
I have long been a believer in E.O. Wilson's idea of biophilia; that we are hard-wired from evolution to need and want contact with nature. To have a healthy life, emotionally and physically, requires this contact. The empirical evidence of this is overwhelming: exposure to nature lowers our blood pressure, lowers stress and alters mood in positive ways, enhances cognitive functioning, and in many ways makes us happy. Exposure to nature is one of the key foundations of a meaningful life.
How much exposure to nature and outdoor natural environments is necessary, though, to ensure healthy child development and a healthy adult life? We don't know for sure but it might be that we need to start examining what is necessary. Are there such things as minimum daily requirements of nature? And what do we make of the different ways we experience nature and the different types of nature that we experience? Is there a good way to begin to think about this?
A powerful idea
Here at the University of Virginia (Charlottesville, VA USA), my colleague Tanya Denckla-Cobb has had a marvelous and indeed brilliant idea. Why not employ a metaphor and tool similar to the nutrition pyramid that has for many years been touted by health professionals and nutritionists as a useful guide for the types and quantity of food we need to eat to be healthy. Call it, as Tanya does, the Nature Pyramid, and we have something at once novel and attention-getting, but potentially very useful in helping to shape discussion about biophilic design and planning. Towards the top end of that nutritional pyramid, as we know, are things that, while important to overall nutrition—meat, dairy sugar, salt—are less healthful in larger quantities and should be consumed in the smallest proportions. ... Continue Reading
July 28, 2014
(This encore publication originally appeared at TNOC on 21 August 2012.)
Walk through any major city and you’ll see vacant land. These are the weed lots, garbage strewn undeveloped spaces, and high crime areas that most urban residents consider blights on the neighborhood. In some cases, neighbors have organized to transform these spaces into community amenities such as shared garden spaces, but all too often these lots persist as unrecognized opportunities for urban improvement. In densely populated cities with sometimes few opportunities for new park or green space development, small vacant lots could provide green relief, especially in low-income areas with reduced access to urban parkland.
And yet, few cities are taking advantage of these underutilized spaces to improve urban biodiversity and provide additional ecosystem services. What’s even more surprising is the vast amount of urban land that is categorized as vacant. Take New York City for example: in this urban metropolis there are 29,782 parcels designated by the city tax code as vacant within the city boundaries, not counting vacant land in the surrounding suburbs and exurbs. This totals more than 7,300 acres of land that could be providing important social and ecological benefits for urban residents.
Here is what we know: Local and regional urban ecosystems provide important services that urban residents rely on for daily living. For example, ecosystems can supply clean water, produce food, absorb air pollution, mitigate urban heat, provide opportunity for recreation, decrease crime, and more. A recent publication from TEEB (The Economics of Ecosystems and Biodiversity) details the list of ecosystem services that can be provided by urban ecosystems.
And yet, all cities do not have the same level of food production, clean water supply, or air pollution removal. Different levels of ecosystem services among cities are due to a myriad of reasons. However, research ... Continue Reading