Shifting Urban Realities and Nature Beyond Parks

Traditionally, cities have been thought of as distinct from nature.  In fact, they have often been considered to be the antithesis of nature.  Ecological science in the past seemed to agree with these assumptions, and ignored cities in favor of wilderness or at least sparsely inhabited places.  During this traditional phase, nature was though of a an unchanging or perhaps a deterministically changing "other." 

Cherokee Park, Louisville KY. Nature in the city.

Into this world of a separate, lasting nature was   If urban and nature were distinct, then the burgeoning populations of cities would need a window onto this separate realm.  Parks would serve as a civilizing influence, a platform for socialization of rural and foreign migrants, a venue for healthful exercise, and a glimpse of the American sublime.  Parks would be an escape hatch from the pressures and pathologies attributed to cities by the scholars and activists of the maturing 19th century.

inserted the American philosophy of urban parks.

Ecology In the City and Ecology In Parks

Ecology, when it finally arrived downtown, would use parks as places to apply its biological toolkit in cities.  Parks, in cities, suburbs and exurbs, would provide the research sites in which to understand the effects of urban environments on organisms, soils, and ultimately on ecosystem processes.  But this understanding would still be framed in terms of the ecology of isolated green spaces in the urban fabric.  Perhaps the human population density or the proportion of impervious surfaces outside parks would serve as explanatory variables, but the emphasis was still on nature versus the urban.  As a participant in that initially cautious exploration of the ecology IN the city, I have to say that many unexpected things were learned -- things like the enhanced nitrogen dynamics of urban forests, the role of exotic earthworms in carbon and nutrient cycling, and the constraints on the regeneration potential of urban forests.

Humans as Components of Ecosystems

At the same time that ecological science was colonizing   By the last third of the 20th century, ecology as a discipline was beginning to adopt some new perspectives.  Primary among these was that humans were involved in almost all ecosystems.  Humans were components -- whether distant or local -- of virtually all ecosystems.  In my own case, the watershed event didn't take place in a city.  Ecological anthropologist Pete Vayda, his student Tim Jessup, and I designed a comparison of natural versus human-created gaps in Bornean rainforest at various distances from a village in East Kalimantan, Indonesia.  Their field work revealed that all canopy gaps combined natural processes and human actions.  If the middle of Borneo failed to provide natural treefall gaps, perhaps there were few places that might boast purely natural environments. 

Long Sungai Barang, Indonesia (by Akubra)

the novel frontier of the city, changing concepts of nature were beginning to crystallize.

The science of ecology began to discover ever more cases of humans as components of ecosystems.  That has become the expected norm.  The ideal of untouched nature is now seen as a very special and rare case.  Indeed, with climate change, perhaps it is fair to say that the nutrient loadings, precipitation amounts and distribution, seasonal shifts, and frequencies of storms, for example, are imposed by human action on even the most remote ecosystems.

Nature Beyond Parks: Ecology OF the City

As ecology in general began to recognize humans as components of ecosystems, so too was urban ecology beginning to explore beyond the comfortable locations of green spaces in cities.  Ecologists were beginning to interact with social scientists and urban designers to conduct research that encompassed entire cities, and indeed entire metropolitan areas.  Over the last 20 years or so, this approach of ecology OF the city, has produced many novel and in some cases quite unexpected findings.  The Baltimore Ecosystem Study, one of the two Long-Term Ecological Research projects located in a city, provides some examples.  One key insight is that the distributed biology of a city contributes to the absorption of nitrogen pollution.  Similarly, the combined vegetation of cities and suburbs contributes to reduced carbon loading into the atmosphere.  A third example is that tree canopy is unambiguously associated with reduced crime in Baltimore neighborhoods, despite variations in social and economic factors.  The exception proves the rule about trees and crime, since only in the three residential neighborhoods that abut abandoned industrial sites was increased crime associated with tree canopy.  This is hypothesized to be due to a low number of "eyes on the street" in such places.

Combining the insights from Borneo and other   Cities, and urban systems more generally, are human ecosystems, containing biological, social, built, and physical components.  The interactions in these ecosystems, which include material and energy transfers, and the movement of influence, information, and power, involve all four components.  Cities are now seen as being suffused with nature.

The Baltimore Human Ecosystem and spatial complexity.

lightly inhabited places, with the discovery of biological activity dispersed throughout urban systems, led to a revision of the traditional idea that cities and nature are antithetical.

Cities and nature can no longer be dichotomized.  However, this insight leaves the second half of the traditional assumptions about nature and cities still to be examined.  What of the view of nature as fixed, deterministic, or equilibrial?  Ecology has come to emphasize process and change rather than stasis.  Dynamics of plant succession, natural and human disturbances, and even changing climate leave natural systems or natural components of urban systems in periodic or constant flux.  Nature is not a fixed thing.  A watershed event in my own understanding of this idea emerged from my work at the Hutcheson Memorial Forest in central New Jersey.  This old-growth mixed-oak forest was set aside for conservation in 1956, using the philosophy of untouched, undisturbed nature.  But over the next five decades unexpected changes took place.  The arrival of exotic species such as Norway maple, wine raspberry, and stilt grass, the explosion of white-tailed deer, and the absence, since 1711, of Native American-set ground fires, have all contributed to the decline of oak dominance in what was once considered a stable forest.  Many of these changes result from the cultural and physical connections of the forest to the adjoining landscape -- the shift from farms to suburbs, the demise of deer hunting, the planting of exotic species in yards, and so on.  Although there are many management tools that could have helped maintain the desired 1950s forest structure and composition, the philosophy that nature is stable, prevented their application.  Nature itself, is dynamic, and when entwined with human actions, unpredictably so.

The Urban as Process

Auch et al. 2004. USGS Circular 1252.

What of the related idea that urbanization proceeds   This model sees urbanization as a universal, one-way journey.  Maps of urban spread as a red blob bleeding out over a green countryside, are common.  Such "red-blob" urbanization maps, obscure important things about cities.  First, they hide even the obvious biologically dominated land and water systems in cities.  This is especially the case with the slivers and fragments that do not excite the attention of planners or managers.  Yet, these small places have contributions to make to biodiversity, water absorption, nutrient retention, microclimate amelioration, and psychological well being.  Second, red-blob urbanization hides the fact that within cities and urban areas, different patches behave differently.  Even as cities grow outward, some core neighborhoods, old commercial districts, and industrial zones may thin and exhibit abandonment and demolition.  Urban change can be via growth, shrinkage, or shift.  Urban ecology has improved as a science so that it now addresses not only the coarse-scale regional expansion of cities and suburbs, but also the ecologically relevant dynamic heterogeneity within them.  Such spatial complexity has great potential to determine ecological functioning of both individual patches and the entire city-suburban-exurban mosaic.

via a set trajectory through mercantile, industrial, and sanitary phases as seen in the Northeastern U.S. or Europe?

Not only do combined city, suburban, and exurban systems change physically, they also change socially and institutionally.  The location of financial investment and disinvestment, the nature and intensity of economies ranging from industrial to service and from formal to informal, the change in household size and composition, the ethnic and demographic shifts in neighborhoods, are all examples of such drivers.   Especially relevant to parks are the changes that may occur in community perceptions, values, and expressed needs.  The desire for passive versus active recreation, for motorized versus muscle-powered activities, for play and sports equipment, for quiet seating, for rustic versus paved paths, and many other contrasting criteria exemplify the diverse judgments that different age cohorts, household types, and social groups may bring to parks. 

The complexity of the ecological role of parks begins to emerge here.  There are parallels in how urban ecology has come to be a more multi-disciplinary and process based discipline.  Starting from its origins as an ecology in the city, an inclusive study of urban systems as social-ecological systems with broad extent and internal variety has evolved.  Early in this scientific history, parks were a window on the effects of cities on ecosystem processes.  Looking at study plots in parks over the long term has confirmed that the parks themselves are dynamic due to succession, natural disturbance, human use, shifting management strategies or financial and human resources available.  Parks are clearly a dynamic element of the urban social and spatial fabric.  They are, to be sure, an element that hosts and amplifies the ecological work that cities and suburbs can do.  It is perhaps no fluke that one of the seeds that led to the establishment of the Baltimore Ecosystem Study was the interaction of Hixon Professor Emeritus Bill Burch with Dr. Ralph Jones, the late director of the Baltimore City Department of Recreation and Parks.  Stimulated by Burch's community-enhancing forestry work in Nepal, Jones invited Burch to explore similar work -- research and action -- in Baltimore.  The parks were key to this work, but like BES, the expanded ecology OF the city project the Jones/Burch interaction helped prepare for, the community forestry approach supported understanding of the entire city -- parks and all.

Some Principles about the Parallel Views of Parks and Urban Ecology

Can this entwined history of ecology and of parks be tamed with some principles?  The first few principles are the antidotes to the urban legends that introduced this essay.

1. Cities are not distinct from nature.  In fact urban systems are hybrids of social, biological, built, and physical components. 

2. Nature is not always stable or even stabilizing.  Nor is it unchanging.  In fact, natural systems and the natural components of cities are highly dynamic, exhibiting probabilistic and non-linear trajectories of change.  The capacity to adapt is a key part of natural change, but in urban areas management is an ingredient of adaptation, and is required to maintain a natural system or key biological component in some desired range.

3. Parks are a just one entryway to nature in cities.  A lot of the nature in cities remains hidden -- even in parks.   Buried streams, nature in slivers on parcel boundaries, abandoned lots and brownfields, biodiversity represented by shy or small organisms -- all are a part of the nature of cities.  Of course, large parks are an important source of ecological wealth in urban systems.  But they are part of a larger network of nature in urban spaces.  The hybrid nature in cities goes well beyond parks.  Urban ecology has evolved -- from ecology IN to ecology OF -- along with this realization.

Next are principles that emerge from improved understanding of both cities and natural processes.  These help link ecological understanding and processes with the role of parks in cities.

4. Parks change.  Parks may have been designed to suit the needs and philosophy of a particular time period.  For example, their design might reflect decisions by elites in the Progressive Era, rather than a more recently articulated bottom up and inclusive process.  Sometimes the changes that parks exhibit were anticipated by their designers and builders, but the need for management may be forgotten by new generations of park users and managers.  Nor may the financial or personnel resources required for management be available over the long term.  Park change requires action.

5. Cities change too, and the demography and culture of park users -- whether across the street or across town -- is not fixed through time.  Park design and program reflect the values and needs of communities, and as communities change so too do the criteria for judging parks.

6. Parks are a process.  This phrase, coined during discussions among Karen Seto, Lisa Schroeder, Rebecca Salminen-Witt, and Colleen Murphy-Dunning of the recent 21st Century Parks conference at Yale, is perfect for weaving the threads in this essay together.  Parks are a complex process linking biology, society, function, and benefit together.  But contemporary urban ecology also focuses on the processes of social-ecological interaction that structure and transform city-suburban-exurban systems.  Our understanding of parks coevolves with the scientific understanding of urban systems, and with the needs, values, and resources of human communities and institutions.  This leaves us at the doorstep of the most inclusive ecology of them all - the ecology for the city.

Steward T.A. Pickett

Cary Institute of Ecosystem Studies

Millbrook NY

Acknowledgement.

A presentation to the Conference entitled "Science and Management of 21st Century Parks," Hixon Center for Urban Ecology, Yale University School of Environmental Studies and Forestry, New Haven, 13 November 2015.

Background Publications

Cadenasso, M. L., and S.T.A. Pickett. 2008. Urban Principles for Ecological Landscape Design and Management: Scientific Fundamentals. Cities and the Environment 1(2): Article 4.

Cadenasso, M. L., and S.T.A. Pickett. 2013.  Three Tides: The Development and State of the Art of Urban Ecological Science. In Resilience in Ecology and Urban Design: Linking Theory and Practice for Sustainable Cities. S.T.A. Pickett, M. L. Cadenasso, and B. McGrath, eds. Pp. 29–46. New York: Springer.

Childers, Daniel L., Mary L. Cadenasso, J. Morgan Grove, et al. 2015. An Ecology for Cities: A Transformational Nexus of Design and Ecology to Advance Climate Change Resilience and Urban Sustainability. Sustainability 7(4): 3774–3791.

Childers, Daniel L., Steward T. A. Pickett, J. Morgan Grove, Laura Ogden, and Alison Whitmer. 2014.  Advancing Urban Sustainability Theory and Action: Challenges and Opportunities. Landscape and Urban Planning 125: 320–328.

Grove, Morgan, Mary L Cadenasso, S. T. A. Pickett, Gary Machlis, and W. R. Burch Jr. 2015. The Baltimore School of Urban Ecology. New Haven: Yale University Press.

McDonnell, M. J., A. K. Hahs, and J. H. Breuste, eds. 2009. Ecology of Cities and Towns: A Comparative Approach. New york: Cambridge University Press.

McHale, Melissa R., Steward T. A. Pickett, Olga Barbosa, et al. 2015. The New Global Urban Realm: Complex, Connected, Diffuse, and Diverse Social-Ecological Systems. Sustainability 7(5): 5211–5240.

Spirn, A. W.  2012. Ecological Urbanism: A Framework for the Design of Resilient Cities. http://www.annewhistonspirn.com/pdf/Spirn-EcoUrbanism-2012.pdf.

Troy, A., J. M. Grove, and J. O’Neil-Dunne. 2012.  The Relationship between Tree Canopy and Crime Rates across an Urban-Rural Gradient in the Greater Baltimore Region. Landscape and Urban Planning 106(3): 262–270.

The Kind of Solution A City Is

A while ago I wrote about Jane Jacobs’ insight that cities were complex systems[i].  The stone that she dropped in the urban pond in 1961 has rippled widely, and the ideas of cities as complex adaptive systems, with emergent properties, good and bad resilience, and non-linear dynamics now guide much cutting edge urban research.

Of course, when Jacobs used the word problem, she meant an intellectual problem to be solved, and her answer suggested complex systems theory as an approach to understanding cities.  But the word “problem” also calls to mind an antonym.  To every problem there might be considered to be a solution.  In this spirit, with apologies to Jane Jacobs, I ask what kind of a solution a city is.

To get to my answer, I do have to admit that some urbanists have interpreted cities as literal problems, in the negative sense.  For example, members of the Chicago School of Urban Sociology in the 1920s emphasized urban pathologies.  They contrasted the issues that existed in cities with the ideal of village and rural life as they experienced it in turn of the 20th century America.  They studied such things as competition among immigrant communities and the distribution and behavior of gangs.  Of course, there are real negatives associated with cities, including pollution, disease contagion, crowding and stress, for example.  Recent research by Bettencourt and West (2010) has pointed out several negative factors, such as crime, that increase at greater than linear rates with city size.

The Lure of the City

A design for urban farming in vacant lands in West Baltimore.
From an urban design studio supervised by Brian McGrath
and Victoria Marshall.

In spite of the negatives of urban living, cities continue to draw humanity to them.  Urban areas are seen as a solution by societies, governments, individuals, and households who vote with their feet or with their policies.  Edward Glaeser (2011) has discussed at length the draws that urban areas clearly hold for people and institutions.  For instance, cities in the broadest sense, are a prime locus of innovation.  The serendipitous interactions of knowledge workers in cafes, bars, restaurants, and informal gatherings are important sources of new ideas and approaches.  Interestingly, the well known power of social media, which can theoretically operate at a global scale in service of creativity, have not replaced the sparks of face-to-face interaction among diverse people.  Institutions such as businesses and universities clearly recognize the power of the city as a source of creative interaction. 

But individuals also yearn for the city for their own reasons.  People seek access to health care, education, jobs, consumer goods, and excitement.  In particular, some urban migrants seek release from the strictures of tradition, the anonymity to pursue a lifestyle not sanctioned in a less urban setting, or to replace a livelihood taken away by industrial agriculture or resource exhaustion in the countryside.  These lures, presented briefly in narrative form can be considered the services or opportunities provided by urban areas. 

Economies of scale are another way to address the lures of the city.  Again, Bettencourt and West (2010) provide statistical meat on the narrative bones.  They show over a range of city sizes a clear savings in terms of per capita infrastructure, resource use, creative products, and so on.  There is roughly a 15% savings in many areas of urban structure and process compared to urban population size.  In a sense, cities and larger urban areas exist to provide these solutions, these lures.

The Contexts for Solutions: Four Dimensions

“The” city is not just one kind of solution, however.  McHale and colleagues (submitted) identify four dimensions of contemporary urbanization: Diversity, Complexity, Diffuseness, and Connectivity.  These four characteristics are intertwined and interacting.  Together they describe what is new and exciting about cities for an urban ecologist.  The conceptual space identifies the realms in which new solutions for sustainability and resilience can be sought in urban social-ecological systems.

Diversity.  Looking at urbanization and urban change around the world reveals a vast diversity of forms.  The wealthy urban cores of Europe surrounded by less well off or segregated suburbs; the Post-World War II sprawl of the United States with thinning and sometimes even shrinking cores; the megacities or Asia; the metropolises of India and Latin America dotted with favelas and shantytowns; the urbanizing former rural “homelands” of South Africa are a part of the great global diversity of urban settlements.  No single simple model describes all the urban systems around the world, or even in a single country any more.

Complexity.  The early history of cities was marked by compactness and often clear differentiation of districts of cosmological significance, trade, residence, and so on.  Cities have always been characterized by heterogeneity of social groups and social standing.  Today, urban areas are marked by great heterogeneity within their perceptual or legal boundaries.  Neighborhoods occupied by different ethnic groups are cheek by jowl, formal and informal institutions divide up the space of service or influence, networks of transportation span walking, public modalities, private vehicles, and opportunistic sharing.  Such networks are layered and changing, and intersect with the patchiness of economic, social, biological, political, and governance features.  Urbanists continue to remark on the stark heterogeneity of urban areas – cities, suburbs, and exurbs – even as the grain size and patch configuration shift with time and use.

Diffuseness.  Hand in hand with complexity is diffuseness.  The boundaries within urban areas are often porous and functionally indistinct in contemporary urban mosaics.  Commuters move great distances, and the direction of travel is often not in a peripheral to central direction.  Many places that had been considered peripheral under older conceptions of single metropolitan cores are now destinations for travel that avoids such cores.  Diffuseness also extends to governance and institutional arrangements.  The issues and solutions for environmental and social problems are managed by collections of governments, non-governmental organizations that operate at various scales, and linked civil society activities.  Likewise investments and disinvestment span neighborhoods, districts, municipalities, and different kinds of lands in extensive urban-rural agglomerations. 

Connectivity.  Closely linked to diffuseness is connectivity.  The porosity of official and vernacular boundaries within urban regions means that connections between the different areas and included ecosystem types can be extensive.  But this connectivity now goes well and commonly beyond any particular urban node or region.  Global connections of finance, resources, wastes, cultural influences, talent, and livelihood are rife.  Consequently, teleconnections or connections at a distance are now contribute much to the form and functioning of urban regional landscapes.  These connections affect farms, rangelands, forest lands, marine and coastal fisheries, for example, as well as more obviously urban places.

Implications for City as Solutions

A typology of water management designs based on how
they use vegetated and non-vegetated components.
Figure by Brian McGrath, Urban Interface.

The global and regional “facts on the ground” of diversity of type, spatial complexity of mosaics, diffuseness of various boundaries in urban territories, and the connectivity at local, regional, and global scales, must be accounted for in solving urban problems.  Indeed, how to exploit these facts is an open question for improving urban sustainability. 

The diversity of urban forms means that there is the opportunity for trying different solutions in different kinds and contexts of urban systems.  It also means that solutions must be locally tuned and evaluated. 

Complexity means that solutions are likely to be heterogeneous even in a single urban region.  Adaptive approaches to governance, including that by formal and by informal institutions, are likely to be required across complex urban regions. 

Diffuseness means that solutions – and problems – will sometimes not respect formal boundaries.  Highly localized control and decision making cannot succeed without at least accounting for the positive and negative effects on adjoining patches or ecosystem types, neighborhoods and districts.  In fact, governance in both its formal and informal manifestations can take advantage of positive outcomes of diffuseness of solutions.

Finally, connectedness means that problems and processes at great distances may have profound effects on any given urban ecosystem.  The accessibility of global markets to global factories and the length of global supply chains means that cities are at the whim of corporate decisions and lifestyle changes in countries and continents distant from their local control.  Solutions must be sensitive to such global connectivity.  Chasing investment that may itself be ephemeral in its geographic focus is a significant challenge.  Environmentally sensitive attempts to buffer a system from capricious decisions elsewhere are certainly called for, but planning for adaptive resilience rather than relying only on the rigidity of hard buffers is a major opportunity.

The Inclusive Sustainability of the Urban

A final opportunity for solution exists.  As the world population becomes increasingly urban, there may be a tendency to forget about the needs, wellbeing, and influences of those who still live in areas designated as rural.  Some nation’s policies are intensely urban focused, such as in China.  Other countries, such as those in Africa, face projected increases in populations such that the urban tide cannot help but rise.  Rural invisibility is a danger in such situations.  Not only must new and existing urban residents be protected from the vulnerabilities of rapid or ill-placed urban development, and exclusion from decision making processes about social and environmental services, but rural residents are at risk as well in this transition.  The connectivity of the urban and the rural in rapidly urbanizing countries is extraordinary.  In Asia and in Africa, for example, “circular migration” for work and in cities and the resultant disruptions of social capital in both city and countryside are existing or emerging issues.  In China, for example, the problem is recognized in policies of “urban-rural integration” which aim to narrow the gap in wealth and services between village and city residents. 

The diversity, complexity, diffuseness, and connectivity of urban settlements and rural and wild lands around the world, in specific municipalities, and in urban megaregions means that sustainability itself becomes a spatially and conceptually complicated set of goals and trajectories.  The kind of solution a city is likewise becomes a multi-dimensional, spatially extensive approach to sustainability.

Bibliography

Bettencourt, L. and G. West. 2010. A unified theory of urban living. Nature 467:912-913. 

Glaeser, E. 2011. Triumph of the city: how our greatest invention makes us richer, smarter, greener, healthier, and happier. Penguin Press, New York.

McHale, Melissa R., STA Pickett, Olga Barbosa, David N Bunn, Mary L Cadenasso, Dan L Childers, Meredith Gartin, George Hess, David M  Iwaniec, Timon McPhearson, M Nils Peterson, Alexandria K Poole, Louie  Rivers III, Shade T Shutters, and Weiqi Zhou.  A New Global Urban Realm:  Complex, Connected, Diffuse, and Diverse Socio-Ecological Systems. Sustainability, submitted.

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[i] http://besdirector.blogspot.com/2011/06/complexity-hidden-nugget-in-jane-jacobs.html

Why Come to Africa to Fully Understand Urbanization?

The transformation of the Earth’s human population to a predominantly urban home is one of the major milestones of the 21st century.  While urbanization in industrialized regions such as the United States and northern Europe has been intense for more than a century, understanding global urbanization requires that we look beyond the cities of those regions. 

Baltimore tells an ecological story that is shaped by the shift from an industrial economy to a service and knowledge economy, and now hopefully toward a sustainable trajectory.  Thinning in the core, shifts in density toward the suburban and exurban fringe are some of the physical features of that story, which are shared by many U.S. cities.  There are many social and ecological effects of these changes, and the Baltimore Ecosystem Study has discovered new features of urban biogeochemistry, physical environment, biodiversity, economic, and policy interactions among them.  However, there is still a need to put our intense focus on the Baltimore region into a broader context.  Where do the urban transformations that Baltimore is experiencing fit within the diverse trajectories and patterns that urbanization represents around the world?  How do we contribute to and fit within a broader theory of urban ecosystems and urban change?

To help answer this question, I have been interacting with colleagues in various countries.  A while ago, I wrote about my experiences in learning about urbanization in China (http://besdirector.blogspot.com/2014/10/baltimore-and-beijing-learning.html).  This year’s urban intellectual adventure has taken me to South Africa.

                               

What do I expect to learn about urbanization at the southern tip of Africa?  This visit follows on intense interactions with Melissa McHale of North Carolina State University and David Bunn, Director of the Knowledge Hub (http://www.knowledgehub.wits.ac.za/) at the University of the Witwatersrand Rural Facility near Bushbuck Ridge, South Africa.  These interactions have resulted in discussions and field trips that have identified features of urbanization that are not part of the standard American patterns of urban change (cf. McHale et al. 2013).

One reason that Africa is an important venue for understanding urbanization is that it is the next and last great frontier for urban intensification on the globe.  Everybody knows that the shifts from traditional, rural residence and lifestyle, agrarian livelihoods and consumption patterns to those that are shaped by urban attitudes, equity, economies, and information flows, are proceeding apace in China and India.  China has a purposeful policy of converting its vast population to the urban realm.  New city building, engulfing of villages in urban megaregions, and replacement of farming livelihoods with industrial employment are hallmarks of this transformation.  The diverse nations of sub-Saharan Africa exhibit an array of urbanization patterns and transformations from which the world might learn.

Africa is still predominantly a rural continent, in spite of hosting some truly huge cities like Lagos.  United Nations has estimated that the population of Africa may quadruple from its 1.1 billion by 2100 (http://worldpopulationreview.com/continents/africa-population/).  Population projections over the course of a century are admittedly subject to some uncertainty, but even if it is off some, the changes promised for Africa are immense.  The growth rate in sub-Saharan Africa is estimated to be especially large. 

This remarkable population growth has profound implications for urbanization in Africa.  Some urban population growth will be the result of people moving to established cities and towns.  Informal settlements and shanty towns are already a part of this trend, and will very likely continue to be.  In other cases, urbanization will involve the conversion of already dense rural areas into new form of settlement in which aspects of rural life ways and urban patterns of culture and consumption mix.  Already a great deal of African urbanization is occurring without the industrial-to-sanitary city conversion that is familiar in North America and Europe.  It is also proceeding with broad connectivity, but with little hard-wired infrastructure.  For example, cell phones link people and provide banking without bricks and mortar, along with new opportunities for scamming the unwary.  African urbanization also exhibits much more spatial and temporal flexibility than we are used to in the Global North.  Commercial and social uses of particular places shift over the course of a day in ways that are virtually unheard of in the highly zoned sanitary city. 

As I begin a month in northeastern South Africa to explore and discuss with colleagues the striking features of urbanization, here are some initial thoughts.  Some are captured in the literature already, and some are points of discussion and curiosity. 

• Africa will be the final frontier of global transformation from rural to urban, but the nature of the resulting patchworks will be different from those in the Global North.
• Urban areas and rural areas are parts of interconnected, patchy regions.
• The linkages between cities and rural areas in Africa flow both ways.  People move back and forth depending on jobs, informal employment, and government grants to the aged and for children.
• Rural and urban lifestyles mix and match with families and “households” spread across regional extents.
• Infrastructure for communication and electrical power may not always follow the gridded model with centralized supply and distribution.
• Consumption may be a more compelling model for urban migrants than the benefits of the industrial or sanitary city.
• Perhaps the biggest general idea, very relevant to Baltimore, is that what looks distinctly urban or distinctly rural may in fact be hybrid systems. 

These points, many of which are the topics of new or needed research, suggest a very different set of models for urbanization and indeed the continued change of urban regions than exist in North America.  In essence they bound a conceptual space in which the structure, function, and change in Baltimore are a subset.  Urban is no longer just about the city.

Acknowledgements.  In addition to host Prof David Bunn, Director of the University of the Witwatersrand Knowledge Hub for Rural Development at the Wits Rural Facility, I have been fortunate to share this visit with Prof Dan Childers from Arizona State University.  Financial support provided by a Fullbright Specialist Program grant, and the Urban Sustainability Research Coordination Network.

Bibliography

Boone, C. G., C. L. Redman, H. Blanco, D. Haase, J. Koch, S. Lwasa, H. Nagendra, S. Pauleit, S. T. A. Pickett, K. C. Seto, and M. Yokohari. 2014. Reconceptualizing land for sustainable urbanity. Pages 313-330 in K. C. Seto and A. Reenberg, editors. Rethinking urban land use in a global era. MIT Press, Cambridge.

Knox, P., editor. 2014. Atlas of cities. Princeton University Press, Princeton.

McHale, M. R., D. N. Bunn, S. T. A. Pickett, and W. Twine. 2013. Urban ecology in a developing world: how advanced socio-ecological theory needs Africa. Frontiers in Ecology and Environment 11:556-564.

Pickett, S. T. A., M. L. Cadenasso, J. M. Grove, P. M. Groffman, L. E. Band, C. G. Boone, W. R. Burch, Jr., C. S. B. Grimmond, J. Hom, J. C. Jenkins, N. L. Law, C. H. Nilon, R. V. Pouyat, K. Szlavecz, P. H. Warren, and M. A. Wilson. 2008. Beyond urban legends: an emerging framework of urban ecology, as illustrated by the Baltimore Ecosystem Study. BioScience 58:139-150.

Simone, A. 2010. City life from Jakarta to Dakar: movements at the crossroads. Routledge, New York.

UN Habitat. 2014. The state of African cities 2014. United Nations, New York.

Baltimore and Beijing: A Learning Expedition to China

Famously Rampant Urbanization

This last summer, I had the pleasure of being hosted as a Visiting International Professor by the Research Center for Eco-Environmental Sciences in Beijing.  This center is part of the Chinese Academy of Sciences, and is the home of the State Key Laboratory of Urban and Regional Ecology.  My goal in spending three months in China was to learn about its form, magnitude, and rate of urbanization. The speed and novelty of urban growth in China are exceptional.  Although some countries have faster annual percent rates of conversion of population from rural to urban, none has a greater absolute number of participants in the process.  Nor do other countries rival China in the extent of the creation of new cities virtually from scratch across broad regions.  It is a perfect place to help put our work in Baltimore in a larger perspective.  In addition, researchers in China are excited and very well prepared to share their new knowledge about urbanization with the rest of the world.

China has for thousands of years been a largely agricultural

country.  The establishment of the People’s Republic saw the proportion of rural residents in the solid majority.  Although Chinese cities boast histories reaching back thousands of years, they were mostly distinct settlements, often retaining ancient defensive walls and sharing key aspects of their city plans.  However, starting from the late 1970s, with the establishment of new policies, the growth of its cities, and the transformation of its population from predominantly rural to mainly city-dwelling, took off.

Chinese urbanization is more than simply the growth of established cities, however.  The idea of urban agglomerations, more recently conceptually deepened in terms of urban megaregions, was one that originated to capture the extraordinary spatial scope of urban change in China and elsewhere in Asia.  There are 23 planned megaregions or urban agglomerations in China (Fang 2011).

Twenty-three existing and planned urban megaregions in China (Fang 2011)

Urban megaregions require understanding urban change in an inclusive way, as something that embraces old city cores, new neighborhoods, novel extensions within large urban administrative units, the engulfing of ancient villages by dense and often high-rise urban fabric, the replacement of agricultural villages by mixed industrial settlements, the demolition of villages and their replacement by superblocks of gated high-rise condos or apartment buildings, and even some modest development of villas, or what we in the U.S. would call single-family houses with yards. 

The richness of the kinds of change and the spatial mosaics produced are novel and not well researched at this time.  Chinese urban ecologists recognize a pressing need to understand the environmental implications of this long list of transformations.

Shifting Policy Landscape

Coming from the United States, I had the impression that China’s strong central government would make urban policy easy to understand, and would also make rational urban plans the norm.  What I learned however, was the existence of a complex, multi-level and multi-sector process of urban change.  In addition, I learned of a fluid policy landscape.  For example, until late July of this year, urban residents had to be registered.  This excluded many people who wished to migrate from the countryside from full participation in urban life and its amenities.  Children of unregistered residents were not permitted to attend public schools. Furthermore, unregistered rural migrants were often crowded into less-than ideal rental units. 

In July 2014 the central government announcemed that this policy, labeled hukou, would apply differently depending on the size cities.  Although the intent is to more evenly spread urbanization across the spectrum of cities, there may well be an pulse in migration to cities as a result.  The social and ecological consequences will be not only interesting, but very likely potent.

The revision of the hukou policy is situated within a larger trajectory of policy evolution in China.  The previous central government policy prioritized industrial development.  The term “development” is used all over the world and is the stuff of headlines and political slogans.  However, it strikes me that most uses in the public discourse in China and elsewhere are rather vague and loaded.  In the past, given the evidence on the ground (and in the heavy, polluted air!) development in China suggested an industrial pathway, and China’s prowess as a maker for the world has been rightly recognized as a result.  But the term development, again based on my personal observations of the culture of consumption that has saturated the big cities with global brands, automobiles with foreign name plates, familiar fast food restaurants, and multi-story shopping malls, also implies a growing emphasis on the provision and acquisition of luxury goods.  The urbanization policy now driving demographic and spatial change in cities, suburbs, with its implications for villages and rural life, shifts emphasis to domestic consumption as a driver for development.

Of course industrially based economic activities and infrastructure will continue to be built and operated in China.  But the new emphasis on urbanization intertwines with a new national policy on the environment.  How these two strands will be reconciled and whether there are the desired environmental – and human well being – outcomes, remains to be seen. 

Chinese urban ecologists are concerned to be part of the dialogue, and many ecological leaders are well placed to help urban planners and municipal authorities to improve the ecological processes and services within their jurisdictions.  I did, however, see evidence of some shortfalls in linking ecological and urbanization processes.

Shortcomings in Contemporary Urbanization

One problem is the sheer speed of urban development.  An interesting and salubrious institution in many large Chinese cities is the city planning museum or planning exhibition hall.  I visited three of these: Beijing, Tianjin, and Shanghai.  In some cases, a glance at the current iteration of the city regional plan was jarring in its dissonance with the facts on the ground.  Much of the greenspace promised by the current plan for Beijing had already disappeared under roads and buildings.  An aspect of the plan that was clearly successful was the protection of the mountain districts in the extensive megacity administrative boundaries of Beijing. These lands were well preserved under the rubric of protecting the air and watersheds on which the city depends, although as a plant ecologist I was interested to know how much impact the transplantation of large, mature trees from the forests into new city and urban developments affected the source stands. 

Tianjin’s urban plan seemed to have clearer bioecological content, and establishing boundaries to protect sensitive forests, lakes, seacoast, and rivers was a part of the plan.  Lands were set aside for parks for urban residents as well, and restoration of wetlands formerly devoted to agriculture in the city boundaries was called for.  The ecological rationale for such conservation and restoration was well laid out in Tianjin’s exhibition hall.

Another issue is the predominance of an economically driven real estate industry, a social institution not unknown in the capitalist west, of course.  My naïve view of the communitarian nature of the Chinese state did not prepare me for the news about the power and efficiency of the private real estate juggernaut in China.

The final shortcoming was the nature of many eco-cities.  As an ecologist and an urbanist who thinks that sustainability is a reasonable strategy for visualizing multi-dimensional improvements in urban social-ecological systems, I had high hopes for the eco-city idea.  However, eco-city developments seem to emphasize a rather narrow suite of strategies, such as engineering efficiencies, multimodal transportation and density, improved onsite stormwater management structures, supplementation of energy sources with renewables, such as wind.  They also have generous street tree plantings and green courtyards in the high-rise residential blocks.  However, the eco-city developments, which were conspicuous in the impressive city models in the planning exhibitions, and evident on the ground in many places, had significant lapses in my view.  I highlight several below.

The rich diversity of commercial opportunities scattered throughout the older urban neighborhoods and even in larger villages, were relegated to centralized shopping malls in the eco-cities.  Three was little to invite residents to interact on the street, and although the individual residential clusters apparently provide recreational amenities behinds their gates, the life on the street seemed depauperate.  This seems to violate one of the tenets of functional urbanism, and was a great disappointment to see so often.  Altogether, the utility of the sustainability concept, which calls for the joint attention to ecological integrity, social functionality and equity, and economic vitality, seems to be poorly realized in much of the urban growth that I saw in China.

Visualizing Urbanization: Opportunities for Enhancement

China also offers insights into the visualization of urban change, a problem that is widely shared.  The process of land conversion and of remaking existing cities is so striking that it is frequently and compellingly represented by a few contrasting colors on GIS maps.  Derived from aerial imagery, such maps represent core urban zones in red, agricultural areas in yellow, and forest and grassland in shades of green.  Because the shifts over five or ten years are so great, such color contrasts over time tell a powerful story.  

Change of land covers in Beijing from 1984 through 2010. Red is
developed urban land.  Copyright
Prof. Weiqi Zhou.  Do not duplicate without permission. 

  

But such coarse classification of urban lands – red blob mapping -- neglects much of the subtlety of urban form.  This is due to both the frequent use of coarse spatial resolutions on the order of 10s of meters, as well as to the fact that these classifications are blind to the rich array of ways in which people actually use different patches.  And here I do not mean use in the sense of simple zones like commercial, industrial, or transportation areas.  Nor does even recognizing the height of buildings reveal key social and ecological relationships that different spatially recognized patches might possess.  There is a great opportunity in China to break down the land covers within urban and urbanizing areas into more specific categories, while recognizing the three dimensional structures of patches.  This approach is one that was pioneered in Baltimore, and I look forward to exploring it with Prof. Weiqi Zhou and other colleagues in China.  The detailed spatial heterogeneity of city regions is a key dimension along which ecological and social understanding have been demonstrated to advance. 

This sort of theoretical perspective on cities also matches very well with the concerns and practices of urban designers, including architects, landscape architects, planners, as well as sociologists concerned with the patchiness of human institutions and social arrangements.  Once more subtle land cover maps are available for Chinese urban regions, the opportunity will arise to understand the social structures, norms and policies, governance arrangements, and of course, the bioecological patterns and processes that exist in those heterogeneous structural mosaics.  The power of fine scale, highly conceptually resolved land classifications in Chinese cities and their rampantly changing urban regions has hardly been tapped.

The Reach of Urbanization

The impact of urbanization in China – or anywhere for that matter -- is not something that is confined to cities and their expanding fringes.  Rather, the growth of cities in China touches even distant villages and rural areas.  Indeed, the national urbanization policies mentioned earlier in this essay guarantee that the link between urban and rural changes will be strong. 

One thing that I explored with Prof Weiqi Zhou and members of his laboratory, was how the continuum of urbanity can be used to advance the understanding of the regional nature of China’s urbanization. 

The continuum of urbanity identifies four dimensions along which the structures and processes of urban change play out: Livelihood, lifestyle, spatial connections including local, regional, and global, and the social and biophysical nature of specific places.  The continuum of urbanity is a conceptual ordering of the shift between urban and rural influences and processes (Boone et al. 2014).  It is not necessarily a literal transect on the ground, but rather the idea applies to various scales and can be used to understand the effects of urbanization at local, regional, and global spatial scales.

The four components of the continuum of urbanity examine 1) how people support themselves and whether and how they participate in formal and informal economies, 2) the nature and expression of their social identities and the implications of social identity for consumption and symbolic decisions, 3) the spatial scope of influences and material connections, including long-distance linkages or tele-connections, and finally 4) the interaction of the other three dimensions with the biological, physical, cultural, and social environments of specific places.  Such specificity of place can apply to very local or to broader areas.  In describing the interaction with place, it is important that sometimes features of the bio-geo-cultural environment act as constraints on the other three dimensions of the continuum of urbanity, and sometimes the environment is in fact changed by the processes represented by the other dimensions.

Urban district rising on recently converted agricultural land
between Beijing and Tianjin.

It is clear that the continuum of urbanity plays out in China in many ways.  The connections between cities and villages are diverse and impactful.  Some villages are swallowed up into expanding cities, with consequent changes in livelihood and lifestyle.  Some villages continue to exist, but become sites of industrial production as factories excluded from polluted cities relocate to rural areas, while some are converted to tourist economies, for example.  In other cases, villages are bought out and the land converted to high-rise, gated apartment blocks with the associated transportation infrastructure.  

And the continuum of urbanity does not stop at China’s borders.  As the official policies to generate a more urban, domestic consumer-based society move forward, a rising middle class demands more meat, for example, which alters land use and livelihoods as far away as Australia and the Americas.  Pig farming, migration of fruit bats to cities, and shifts in bat-borne disease risk are outcomes of the continuum of urbanity that spans from China to Australia. 

The continuum of urbanity represents a useful way to organize research on the extensive effects of urban development in China.  It can focus on fine scale heterogeneity within cities, as called for above, or it can expose the continental and global effects of urbanization.  The mutual relationships of urban regions linked in a global system are eliciting greater attention in the world of economics, and ecology will change at both ends of any urban teleconnections.

An Urban Ecological Future

The changes in China’s urban realm, and its megaregional, continental, and global reach are vast research frontiers.  To summarize what I learned in China:

1. There is great need for describing, modeling, and working with spatial heterogeneity at refined conceptual resolutions and at various spatial grains.

2. Social phenomena and dynamics need to be better connected with ecological and physical data and representations of urban change.

3. The connections between both former and persistent-but-altered rural zones and villages with cities are an open research task.

4. Addressing the shortcomings of some “eco-city” approaches, and applying sustainability as a linked set of social, environmental, and economic goals are important challenges.

The richness, speed, and nature of Chinese urbanization are a useful intellectual foil to the specific history and trajectory of urban change in Baltimore.  China defines at least one extreme of the conceptual space that all urban social-ecological research and application occupy.  Opportunities for comparison and for collaboration are great.

Acknowledgments.

My trip to China was supported by an International Visiting

Professorship from the Chinese Academy of Sciences.  My hosts were Prof. Weiqi Zhou and Prof. Zhiyun Ouyang of the State Key Laboratory of Urban and Regional Ecology of the Research Center for Eco-Environmental Sciences.  The graduate students and faculty in Prof. Zhou’s lab were indispensable guides and warm friends, and I am indebted to them all for many kindnesses, including compensating for my attempts to apply New York rules for jaywalking in an inappropriate cultural context.  I know a lot more about urbanism and urban ecology now than I did when I landed in Beijing.  They also taught me how to make dumplings.

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