Monday, December 13, 2010

Urban Ecology: Use and Abuse

In the first two decades of the 20th century, two new scholarly disciplines were being established in the United States. One was the biological science of ecology, and one was sociology. Although both had deeper European roots, and began to flourish in several American universities, there was one school that was a seedbed for both: the University of Chicago. Historian Jennifer S. Light examines the relationship of these two disciplinary schools and the decades long ramifications of that intellectual hybridization on American urban policy (Light 2009). Her book is much richer in insights about urbanism and the linkage of ecology and policy than can be represented in a brief essay, so I encourage people to peruse her work directly.

The biological ecologists at the University of Chicago had been instrumental in elucidating the patterns and processes of change in plant communities through time. Chicago’s Henry Chandler Cowles in 1899 had published a long, multi-part paper that described the succession of plant communities on the dunes at the southern end of Lake Michigan (Cowles 1899). As the land was still rising in elevation, rebounding from the weight of the thick glaciers that had melted away some 12,000 years previously, new sandy substrate was exposed at the margin of the lake. Cowles (pronounced like the stuff burned in a furnace) described the ever taller and more complex plant communities that occupied the bands of surfaces that were located farther and farther from the lake shore.

The kinds of patterns that Cowles described as one moves from the lake shore inland were generalized by Frederick E. Clements (Clements 1916). Clements generated a theory of succession, in which he proposed that plant communities experienced progressive trends of change, leading to a diverse, stable assemblage. He likened the temporal patterns of change in assemblages of plants in the field to the life cycle an organism. Communities of plants were said to go through phases of colonization, growth, and maturation (Pickett and Cadenasso 2005).

A version of Clements’ theory was enthusiastically adopted by he Chicago sociologists in their attempt to understand their rapidly changing metropolis (Light 2009). They saw the city as a series of rings surrounding downtown, in which new immigrants invaded near the commercial core, and through competition moved outward. Like the first theory of plant succession, the sociological explanation of spatial pattern was considered to be a set life cycle. However, one important difference was that the sociologists substituted a decadent, blighted community as the end point as opposed to the idealized diverse, tall, and spatially complex “climax” forest.

The sociologists were apparently unaware of problems that were emerging with the theory of succession in biology (Miles 1979). Cowles’ original assumptions had some problems – sites that had better developed plant communities on the lake shore transect in some cases turned out to be different in other ways than just age of the substrate. Furthermore, Clements’ grand theory of succession as the life cycle of an organism was ultimately found to too rigid and methodologically problematical. Succession actually involved much variety in the patterns of change, and the mixture of causes was much more contingent on history and the landscape context than the developmental biology of individual organisms. The progressive theory of succession formulated by Clements was in dispute as early as 1917, and alternative views of the causes and patterns of succession were being worked out by a number of plant ecologists, some elsewhere in Illinois (Gleason 1917).

Why were the Chicago School sociologists so enamored of the life cycle metaphor they took and modified from ecology? Chicago had doubled in population in the early years of the 20th century, and was absorbing massive numbers of migrants from the American South and from Southern and Eastern Europe. These migrants represented groups that had largely been absent from Chicago before. They saw the effects of these waves of migrants as a succession that led to blighted neighborhoods. Slums and social pathologies were identified as problems to be solved by identifying where a neighborhood was in its life cycle, and intervening to counteract any tendencies toward blight.

Several kinds of intervention were possible. One social intervention was exemplified by the work of “settlement houses,” which were intended to introduce new migrants to values held by the predominant antecedent culture of a city. Another intervention was to attempt to keep some neighborhoods from changing to accommodate new migrants. This was accomplished by discriminatory laws or discriminatory lending practices. A third was urban planning, which could in cases where blight had proceeded beyond tolerable limits, be employed to clear slums and install new housing and neighborhood layouts intended to promote desirable social interactions. Light documents the intellectual lineages, the persistence of the life cycle approach, and the pervasive effects of this perversion of ecological thinking on the form of late 20th century American cities.

What Does This Mean for BES?

One lesson for an interdisciplinary research program emerges from Light’s analysis. The ecology that was used by the Chicago School sociologists was a superficial metaphor. Communities changed through time, that change was driven by competition, and expressed itself in an inexorable life cycle. The real mechanistic complexity that was emerging from scientific research in biological ecology was not apparently known to the Chicago sociologists. The metaphor was established in sociology through reading of ecological texts, but apparently not through conversation with practicing bioecological researchers. The complexity, the controversy, and the alternative models of vegetation change did not become part of the toolkit of the social science deployed to understand rapidly changing cities. Nor were these features of understanding community and spatial dynamics available to those who shaped federal policy of urban life cycles – the policy that supported urban renewal.

Although metaphor is a powerful bridge between disciplines, and from disciplines to application, substantive dialog between researchers and practitioners who know the frontiers of their disciplines is a sounder link. Analogy and metaphor are only tools for starting the dialog. Light provides a compelling analysis that will be of value to all urban researchers and practitioners.

References Cited

Clements, F. E. 1916. Plant succession: an analysis of the development of vegetation. Carnegie Institution of Washington, Washington.

Cowles, H. C. 1899. The ecological relations of the vegetation on the sand dune of Lake Michigan. Botanical Gazette 27:95-117,167.

Gleason, H. A. 1917. The structure and development of the plant association. Bulletin of the Torrey Botanical Club 44:463-481.

Light, J. S. 2009. The nature of cities: ecological visions and the American urban professions 1920-1960. Johns Hopkins University Press, Baltimore.

Miles, J. 1979. Vegetation dynamics. Wiley, New York.

Pickett, S. T. A. and M. L. Cadenasso. 2005. Vegetation succession. Pages 172-198 in E. van der Maarel, editor. Vegetation Ecology. Malden, MA, Blackwell Publishing.

Photo by Brian P. McGrath.

Wednesday, November 10, 2010

The New BES

The original guiding questions for the Baltimore Ecosystem Study (BES) are instances of the three most fundamental things that researchers can ask: How is the system I am interested in put together and how does it change through time? How does the system interact with and influence matter and energy flows? What difference does this knowledge make?

These questions have served us well over the first dozen years of the Baltimore Ecosystem Study. So why are we adopting a new guiding question for the third phase of BES, which has been recently funded by the National Science Foundation for another six years? Why change a good thing? In fact, shouldn’t a long-term study keep doing the same thing?

Stability of effort is one of the advantages and requirements of a long-term project. Certain things must be measured consistently for many years to disentangle what causes what, and how the causes change. But that stability must be balanced by an ability to respond to change. Two kinds of change are important for motivating BES III.

One of the changes we must track is the development of urban ecology itself as an interdisciplinary science. Urban ecology is becoming more integrated across research disciplines. We must take advantage of more tightly sewn seams between social-economic and biophysical sciences. This requires us to explore new models and new joint data projects. An additional change in the science is its improving connections with urban professions and policy makers. As a result, concerns with climate change and with sustainability must become more a part of our efforts. The emergence of new views of urban sustainability and resilience drive new scientific questions.

We have adopted the idea that cities – in the broadest sense – are evolving from a sanitary city model to a sustainable city model. The sanitary city was a solution to the stresses and contamination of the industrial city in which pollution, disease, and social dislocations were seen as major problems. Brilliant engineering and public health solutions were developed, and master planning segregated harmful activities from those places where citizens lived and played. This approach was refined from the middle of the 19th century through most of the 20th century. It focused on separate sectors of urban activity, in which focused solutions were sought in isolation. This history has been reviewed in a very readable book by Martin Melosi (2000), entitled The Sanitary City.

As many cities in the global north have shifted from an emphasis on industrial production to service economies, and as many cities in the global south have even leapfrogged into service and consumption models with no intervening industrial phase, new approaches to urban management are emerging worldwide. As urban dwellers, policy makers, and designers have come to recognize that healthy economies, equitable access to environmental benefits, and resilient social networks are all required for quality of life in urban areas, the sustainability worldview has been more widely and enthusiastically embraced. Sustainability concepts suggest that cities should be designed and revitalized to include more ecological processes, to reduce resource demand and waste production, and to facilitate the formation and function of positive social networks. Of course, economic vitality is a goal as well, and one that usually gets the lion’s share of attention. Yet all these components of sustainability must receive equal weight in decision making, and that need suggests that decision making be based on improved communication and goal-setting across social and institutional boundaries. Based on the sustainability model, cities should be conceived of and managed as complex socio-ecological systems, rather than sectors solving important but narrow engineering problems. Grove (2010) has outlined the emergence of the sustainable city, and provides an entry point into the literature.

A New Guiding Research Question

The main question that emerged from our years of planning for BES III is “How do biogeophysical and social adaptive processes influence and respond to policies aimed at enhancing sustainability in the Baltimore region?” This question assumes that the policies in place and evolving in Baltimore City, Baltimore County, and the State of Maryland will themselves lead to changes in structures, activities, and socio-ecological interactions in the region. Climate change is a key aspect of the discourse and planning for a more sustainable metropolitan Baltimore. Adaptive processes are the whole range of conditions, mechanisms, resources, and actions – in both the biophysical and social realms of the Baltimore ecosystem – that can drive or constrain the extent to which sustainability is achieved.

Focusing on sustainability plans, policies, and actions suggests three, more specific research areas: 1) How do adaptive processes change as the metropolis as a whole or different segments within it evolve from a sanitary city approach to a sustainable city approach? 2) What scenarios do current and alternative policies aimed at sustainability suggest? 3) How can information exchange and education improve adaptive processes?

BES III will embody the working out of these large issues. There are fundamental scientific theories that resonate with these questions. We have chosen the theory of locational choice by households and firms, the theory of spatial heterogeneity in biodiversity, and the concept of an engineered urban stream continuum as our touchstones for linking the paradigm of sustainability with research. The community of scholars, researchers, and educators in BES have taken the understanding and application of the transition from the sanitary to the sustainable city as their motivation for the next six years of work.


Grove, J.M. 2010. Cities: Managing Densely Settled Social–Ecological Systems. Pp 281-294 In F. Stuart Chapin, III, Gary P. Kofinas and Carl Folke (eds.) Principles of Ecosystem Stewardship Resilience-Based Natural Resource Management in a Changing World. Springer, New York.

Melosi, M. V. 2000. The Sanitary City: Urban Infrastructure in America from Colonial Times to the Present. Johns Hopkins University Press, Baltimore.

Wednesday, October 20, 2010

The Journal, Nature, Highlights Cities.

The journal Nature has featured the need for research in urban areas in its October 20th issue. The editors introduce the issue in an editorial that says, in part: "Scientists are city people. More than one-tenth of the workforce in the Washington DC metropolitan area are scientists and engineers. Beijing has more than 160,000 professionals in research and development. Worldwide, resources such as universities and researchers are concentrated in urban areas. So why do so many scientists ignore the needs of our cities? It is time to encourage scientists and universities to pay more attention to urban areas, and Nature this week includes a package of articles about researchers and cities" (Editorial, "Save our Cities," Nature 467: 883-884 doi 10.1038/46788b).

For the details, follow this link from your school or local library: The articles appear in volume 467, issue number 7318. In addition to the editorial quoted above, the special feature includes an overview of "The Urban Equation," a geographic description with excellent maps of urban population and growth entitled "The Century of the City," an article by Cynthia Rosenzweig et al. on "Cities Lead the Way in Climate-Change Action," and a synthesis of urbanization by Bettencourt and West entitled "A Unified Theory of Urban Living."

Members of the Baltimore Ecosystem Study and those interested in urban ecology should find this collection of articles of value.

Thursday, March 11, 2010

Baltimore Ecosystem Study: Renewal Proposal

The Baltimore Ecosystem Study LTER renewal proposal was submitted for the February 1st 2010 deadline. This was a massive effort involving the contributions of more than forty researchers, educators, community practitioners, and administrative and information management staff. The proposal emerged from a series of meetings begun more than two years ago. These meetings, which have been discussed in previous posts, involved the entire BES community in identifying crucial measurements to continue, important research to add, and new strategies to better integrate our biogeophysical and social research approaches. Continuing conversations with our partners at various levels of government identified points of contact between their policy and management concerns and the emerging research and education plans.

The title of the proposal includes the phrase, “from sanitary to sustainable city,” in recognition of the emerging vision of sustainability in the world’s growing urban realm, and to help us better link with on the ground activities in Baltimore City, Baltimore County, and the State of Maryland. We use the word city here to represent the entire city-suburb-exurban (CSE) system. The sanitary city identifies the present form and function of the CSE, with its separate, engineered systems and management by sector – housing, transport, waste, health, and so on. The sanitary city is the result of more than a century of efforts to overcome the negative effects of the industrial city and reduce the risks of contagion in dense agglomerations of people. The sanitary city achieved many of its local benefits by transferring waste downstream, downwind, or segregating disamenities in disempowered neighborhoods. The sustainable city seeks to meet environmental goals throughout its extent and beyond, while at the same time improving social conditions and economic opportunities. The move toward sustainability in systems reinforces the cross-disciplinary integration we seek by requiring attention to the environmental, the social, and the economic structures and processes in our study region.

A sustainability focus also encourages us to look to the future. An approach we will develop in cooperation with our partners in government and in communities is scenario building. This is a modeling technique that will explore alternative forms that change can take. Scenarios can be generated that explore responses to policies, or to projected environmental conditions. Policies thus become a part of the landscape we study as much as the effects of climate change or shifts in investment and human population.

We have spent more than a dozen years laying a firm foundation of understanding the structure and function of metropolitan Baltimore as a socio-ecological system. Our proposed new work aims to focus and refine our theoretical framework. The planning process identified three theoretical areas, each with its own disciplinary interest and motivation, but which we believe will also stimulate integration. One is locational choice theory for households and firms, which combines economic and social processes. The second is biological metacommunity theory adapted for CSE systems. The third is the urban stream dis/continuum concept, a version of the river continuum originally developed for non-urban watersheds. These three theories advance our existing concerns with socio-demographic structure and dynamics, with urban biodiversity, and with inhabited and infrastructurally invested watersheds. Linkages through the economics of decision making, feedbacks between biota and different scales of social features, and exposing the complexities of connection and disconnection in CSE watersheds are benefits that can emerge from these new theoretical foci.

For more information, we invite you to peruse our renewal proposal, available as a pdf here or as a zip file here.