How Does a Long-Term Study Adjust Its Framework while Preserving Data Integrity?

Long-term ecological research is faced with seemingly contradictory constraints: It must maintain a consistent stream of rigorously comparable data over time while at the same time responding to conceptual and theoretical changes in the disciplines underlying those data.  How can such opposing  constraints be reconciled? 

BES has faced this challenge in developing its most recent proposal.  It was required to shift from a framework that -- although it highlighted a frontier topic in the understanding of social-ecological systems -- proved to be problematical for many readers.  In response, members of the project management team took a step back and sought ways to improve the conceptual framework.  First, they wanted to simplify the conceptual framework.  Second, they wanted to increase its parallelism with frameworks of other LTER sites.  Finally, they wanted to emphasize the interactions on multiple scales that caused the changes in urban social-ecological systems over time.

This stepping back took us to the foundations of BES.  The project was founded to examine the basic biophysical structures and functions in an urban system, and how they interacted with social processes, all in a context of change. 

The Founding Ideas of BES

So the founding question of BES asked: How do biological and social patch dynamics combine to shape and change a metropolitan area?  This question was operationalized by applying the watershed concept in a city-suburban-exurban matrix, and by examining nested hierarchies of social, biological, soil, and hydrological processes as potential causes of urban change. 

In revisiting the framework, we looked at what the first three phases of BES had accomplished, and what they suggested about refinements in the concepts.  Furthermore, we looked at the improved understanding of climate change and globalization that had developed over the nearly 20 year history of BES, to see what those insights suggested about revision of our framework. 

New Pressures in the System

It was clear that effects of climate change through sea level rise, increases in storm intensity and frequency, risk of drought, increase in heat waves, and shifts in species ranges were likely to alter the structure and functioning of our urban ecosystem.  Furthermore, globalization was likely to alter human migrations, increase the pressure from introduced and/or invasive plants, animals, pests, and diseases, as well as work continuing social-demographic changes within our region.  These ideas had not played significant roles in the initial conceptualization of BES, which was concerned primarily with testing how well ecological approaches worked in an environment where they had not been tried previously.

Conceptual Refinement about Urban Ecosystems

An additional refinement emerging from BES and other urban social-ecological research also played a role in the evolving framework.  Early on, leaders of BES and its sibling LTER, the Central Arizona Phoenix project, had pointed out the difference in studying ecology in the city versus studying ecology of the city.  The latter approach required an integrative, interdisciplinary stance and investigated all habitats in an urban-suburban-exurban matrix, not just the conspicuously green patches. 

Taking ecology of the city seriously generated a new land cover conceptualization and classification, and required examining the intimate feedbacks between social and biophysical processes over various temporal scales.  Indeed, the urban ecosystem is now seen as "coproduced" by natural and social processes, and consequently, to possess a hybrid social-ecological-technological structure (Rademacher et al. 2018).

Key Features of a New Framework

These insights, empirical advances, and conceptual refinements have led us to propose a new framework to support our continued collection and analysis of long-term data in the urban ecosystem.  The framework divides the research concerns into 1) exogenous drivers of change, 2) the structure of the urban ecosystem, consisting of biological, physical, constructed, and social components, and 3) the functional responses of the urban ecosystem.  All of these aspects -- drivers, structure, and responses -- interact with each other through time.  In addition, the functional responses of the urban ecosystem feed back onto its structure.  In a system that includes humans as individuals, groups, and institutions, the feedbacks may involve learning and adaptation or adjustment.

Exogenous Drivers. 

Exogenous drivers are those that originate or are controlled from outside of the local or regional urban mosaic.  Climate change is clearly exogenous, as are regional patterns of atmospheric deposition of gasses and particulate pollution.  Much of the economy of urban regions is driven by national and international investments, policy, allocation of jobs, and movement of resources and commodities.  Governance anchored beyond the city, such as requirements of regional compacts, state law and regulation, federal regulations, and private-public interactions, can affect a metropolis or its parts.  Technology emerging elsewhere may also alter the fluxes of matter and energy available to a city, and human population can be altered by regional, national, or international migration numbers and directions. 

Some of the factors enumerated as "exogenous" may, if they are managed or shaped within the city or metropolis, act as local or endogenous factors.  It is the origin and distance which determines exogeneity, not the specific type of flux or influence.  For example, the movement of people within a metropolis could reflect local environmental perceptions, behaviors, and organizational networks.

Ecosystem Structure. 

Exogenous and internal influences come together in the structure of the urban ecosystem.  Like all human ecosystems, urban areas consist of the biological organisms and the physical environment, but also of the various human and social structures, and the constructed environment.  The interactions among these four components drive the functional responses of the urban ecosystem.  All four urban ecosystem components are reflected in the ecosystem function.

Functional Responses. 

The functional responses are divided into three linked process realms, long used to organize BES data collection. Watershed biogeochemistry addresses the amount and content of water flowing through constructed infrastructure and biophysical features of catchments.  Local ecosystem production and nutrient transformations are driven by the biota, represented by plant, animal, and microbial communities. These are indexed by key sentinel species.  Human environmental perceptions, behaviors, and the actions of organizations constitute the social functions of the urban ecosystem.  Clearly, all three functional realms interact with each other.  Equally clearly, the functional interactions feed back on the structural filter by which external drivers impact the system.

Similarity with Other LTER Site Frameworks

This new framework is intended to be readily interpretable by ecologists working outside of urban areas as well as those who focus on urban places.  In fact, the general schema for the framework is very similar to that of the Hubbard Brook Ecosystem Study LTER, located in the forests of the White Mountains of New Hampshire.  Hubbard Brook is one of the oldest LTER projects, and focuses on understanding the dynamics of forested watersheds under the influence of exogenous factors and local management choices and ecological succession.  Exogenous factors are well illustrated by the Hubbard Brook study, where acid rain from distant sources was first identified in North America.  Current examples of climate changes include the role of reduced snow cover, and intensification of winter storms.  Of the existing LTER sites, the vast majority include some sort of exogenous factors in their roster of drivers.  Climate change, sea level rise, and human generated land use change are commonly identified as exogenous drivers.

Accommodating Long-Term Data 

For nearly 20 years, BES has collected continuous or repeated data sets on climate and weather, watershed hydrology, nutrient export,  water quality, biodiversity and key biotic populations, soil processes, land cover and land use, social structures, and social dynamics.  These data sets are arrayed across the seven core areas required of urban LTER sites, as stated in NSF's original request for proposals in 1997 (Table 1).

Table 1. Major BES research areas and their distribution across the LTER core research areas.

BES has revised its conceptual framework by identifying the fundamental ecosystem structures and processes represented by its ongoing, long-term data collection, while at the same time organizing the structures and processes differently than in its original conception.  In this way, we hope to have clarified the big ideas that motivate and tie together the data streams emerging from a still under-studied ecosystem type.  The framework combines some of the most fundamental ideas from ecosystem science with the novel structure and large changes represented by urban systems.

Steward Pickett and Emma Rosi

Background Literature

Cadenasso, M. L., S. T. A. Pickett, and J. M. Grove. 2006. Integrative approaches to investigating human-natural systems: the Baltimore ecosystem study. Natures Sciences Societes 14:4–14.

Pickett, S. T. A., M. L. Cadenasso, E. J. Rosi-Marshall, K. T. Belt, P. M. Groffman, J. M. Grove, E. G. Irwin, S. S. Kaushal, S. L. LaDeau, C. H. Nilon, C. M. Swan, and P. S. Warren. 2017. Dynamic heterogeneity: a framework to promote ecological integration and hypothesis generation in urban systems. Urban Ecosystems 20:1–14. DOI: 10.1007/s11252-016-0574-9

Rademacher, A., M. L. Cadenasso, and S. T. A. Pickett. 2018. From feedbacks to coproduction: Toward an integrated conceptual framework for urban ecosystems. Urban Ecosystems. DOI: 10.1007/s11252-018-0751-0

Zhou, W., S. T. A. Pickett, and M. L. Cadenasso. 2017. Shifting concepts of urban spatial heterogeneity and their implications for sustainability. Landscape Ecology 32:15–30. DOI: 10.1007/s10980-016-0432-4

Two Ways to Discover Disturbance

Ecological disturbance is often defined as an event that disrupts the structure of a specific system (Pickett & White, 1985).  This kind of material or physical disruption is important because it can result in changes in behavior of the system, or leave heterogeneous structural legacies that affect the system in the future (Pickett, Cadenasso, & Jones, 2000; Wiens, 2000).  Such a general and potentially significant ecological process requires conceptual clarity in order to use it successfully (Pickett, Kolasa, Armesto, & Collins, 1989).  As is often the case, seemingly simple definitions actually require great subtlety in their application.  Disturbance invites that kind of attention. 

This essay shows that disturbance can be recognized in two ways.  The first is based on empirical experience with events that have, in the past, commonly acted to disrupt structure of various systems.  This approach can be called event-based detection of disturbance.  The second approach allows disturbance as structural alteration to emerge from the comparison of different kinds of trajectories in a system.  Using such a lens, disturbance shows up as the intersection of long-term data about phenomena or processes with long-term data on system structure or function.  This second approach can be labeled emergent detection of disturbance.  This distinction may be important when disturbance is studied in systems where there is little prior empirical experience, or where interaction of events may be particularly complex.

Background: Disturbance as Process

Although disturbance is one of ecology's fundamental processes, the concept continues to be refined as more examples are brought to bear on understanding disturbance (Peters et al., 2011).  Disturbance can be conceived as a process, of which a conspicuous or powerful event is only a part.  

The process as a whole actually involves interaction between the forces embodied in the event and the characteristics of an ecological system that is exposed to the event.  The system characteristics govern how the forces can affect the system of interest.  In this sense, disturbance can be seen as a complex process because of the multiple interactions between an event and a place. 

The description above requires a caveat.  The term system can be used in different ways in reference to disturbance.  One arises because it may be reasonable to consider disturbance itself as a conceptual system of interacting components and phenomena.  "Disturbance as a system" refers to a conceptual model of the event, forces, and characteristics of places that may be affected by disturbance (Figure 1).  In contrast to a conceptual model involving disturbance, "the system of interest," uses the word system to refer to a concrete location, habitat, place, or ecosystem. 

Figure 1. Disturbance as a complex process (based on Peters et al. 2011 and Grimm et al. 2017)

Event-Based Detection of Disturbance

The refined conceptualization of disturbance, assumed here as background, suggests that there is more than one way to recognize or detect a disturbance.  The first is familiar, and rather intuitive when applied to scales comfortable to humans.  If we can travel through a system, and observe its dynamics at multiple points in time, it is usually easy to identify what a disturbance is.  Walking through a forest after a major wind storm may reveal newly fallen canopy trees, with their upturned roots, and the soil pit from which the roots were wrenched.  In that forest, some trees may have been snapped by wind, and saplings and immature trees may have been broken or bent as canopy trees fell on them.  The scene may be a complex jumble of altered forest structure from the canopy to the subsoil.  This is clearly a disturbance to the formerly intact forest ecosystem, and the motive force of wind equally clear as a driver.  Similarly, walking into a forest some time after a fire, whether one that "crowned" and burned the canopy, or one that was restricted to the litter layer on the ground, shows structural disruption of the prior forest structure.  New seedlings, surviving saplings released from competition with canopy trees, and understory herbaceous plants may respond by faster growth or enhanced reproduction following disturbance.  Such a human-scaled, intuitive recognition of disturbance events has led to familiar, if imprecise, statements that floods, fires, ice storms, landslides, hurricanes, and tornadoes "are disturbances" a priori.

The general model of disturbance (Figure 1) captures these intuitive cases that are linked to human size and experience quite well.  The model suggests though, that understanding exactly how the force of wind, the weight of ice, or the chemistry of combustion affected particular parts of an area require that the nature of the potentially impacted system or area to be known.  This requirement may be realized by rigorous and long-term observation of a system.  But generally, the focus on events matches the requirements of the general model well.  This use of the model is an example of the event-based approach to detecting disturbance.

Emergent Detection of Disturbance

Emergence is a contrasting approach to discovering disturbance.  Not everything that causes disturbance may be the result of a familiar or human-scaled kinds of event, like a hurricane or a flood.  In such cases, the disruption of system structure may result from the application of unexpected or non-intuitive forces.  Non-intuitive forces may exist on scales difficult for individual people to comprehend intuitively.  In addition, such unfamiliar drivers of disturbance may be especially characteristic of social-ecological systems.  The difficulty here is that powerful social-ecological drivers may seem ordinary and unexceptional to people in daily life.  Processes of real estate investment, employment opportunities, or government regulation may not seem at first glance to be the stuff of disturbance.  This invisibility of social-economic drivers is in part a result of the hybrid nature of such systems.  Hybridity or social-ecological-technological system structure means that the forces may have material and social momentum. 

What does such hybridity of forces mean in concrete terms?  If disturbance is an event that disrupts system structure, what counts as an effective event depends very much on what the model of the system is.  The requirement that an explicit model be used to determine what is and what is not a disturbance is an often neglected fundamental of disturbance studies.  Models of hybrid systems can express very different kinds of structures, all of which are important facets of the larger, more inclusive urban ecosystem.  The models state what components the system contains, and how the components of the system are networked together.  For example, social-ecological systems can have structures that serve to transfer information, or transmit social expectations.  Information may include the flows of capital or credit, and expectations may be transmitted in the form of such things as social norms or neighborhood cohesion. 

What can alter the such a socially inflected structure?  Of course, the physical disruption of communication infrastructure can be a disturbance.  This is very much like classical disturbance in ecology.  Alternatively, the physical networks may persist while the capacity of the social network to transfer information may break down due to the removal of an institutional node in the flow of information.  Or restriction of loans in specific areas may disrupt the financial resources that permits people to maintain and refurbish housing stock; ultimately this disruption of the financial system may appear as a material disruption in the urban fabric as buildings are abandoned and perhaps demolished. 

Examples of social features of structure can be labeled a "social contract," or an "ecology of prestige," each of which communicates expectations that influence how people interact in particular places.  A social contract in a African American neighborhood is a structure that can be disrupted by the novel, and perhaps conflicting, expectations about how public space is used and regulated that are put in place by gentrification.  The ecology of prestige is a place-specific social structure expressing a shared aesthetic that directly affects environmental form and management.

Figure 2. Illustration of emergence of disturbance as the intersection of a trajectory of lightning strkes and increasing density of wood stems.  Below a certain threshold density an ignition will not result in fire spread. Hence, there would be no disturbance of the larger landscape.

Disturbances of this kind are particularly complex, and may be more readily discovered by examining the trajectories of change in urban systems than by focusing on specific kinds of physical events (Figure 2).  Trajectories in important biophysical features of urban systems should of course be monitored, as should drivers from outside the system that can cause structural disruption.  However, the events that contribute to disturbance as a process can also arise within the system due to the interaction of changes in various system components. 

The fact that disturbance can arise in two ways in social-ecological-technological systems is a part of the complexity of urban ecology that has helped refine the understanding of one of ecology's basic phenomena.  The fact that the Long-Term Ecological Research program listed disturbance as one of the five core areas for research in its study sites is a symbol of the importance of disturbance across a range of system conceptions including populations, communities, landscapes, and ecosystems.  Disturbance can be hypothesized a priori in for some kinds of models, but must be detected analytically in others.

Steward Pickett

Literature Cited

Grimm, N. B., Pickett, S. T. A., Hale, R. L., & Cadenasso, M. L. (2017). Does the ecological concept of disturbance have utility in urban social-ecological-technological systems? Ecosystem Health and Sustainability, 3(1). doi:10.1002/ehs2.1255

Peters, D. P. C., Lugo, A. E., Chapin, F. S., III, Pickett, S. T. A., Duniway, M., Rocha, A. V., … Jones, J. (2011). Cross-system comparisons elucidate distrubance complexities and generalities. Ecosphere, 2, art 81. doi:10.1890/ES11-00115.1

Pickett, S. T. A., Cadenasso, M. L., & Jones, C. G. (2000). Generation of heterogeneity by organisms: creation, maintenance, and transformation. In M. L. Hutchings, E. A. John, & A. J. A. Stewart (Eds.), Ecological consequences of habitat heterogeneity. Malden, MA: Blackwell.

Pickett, S. T. A., Kolasa, J., Armesto, J. J., & Collins, S. L. (1989). The Ecological Concept of Disturbance and Its Expression at Various Hierarchical Levels. Oikos, 54(2), 129–136. doi:10.2307/3565258

Pickett, S. T. A., & White, P. S. (Eds.). (1985). The Ecology of Natural Disturbance and Patch Dynamics. Orlando: Academic Press.

Wiens, J. (2000). Ecological heterogeneity: an ontogeny of concepts and approaches. In M. J. Hutchins & A. J. A. Stewart (Eds.), The ecological consequences of environmental heterogeneity. Malden, MA: Blackwell.

Asphalt: Evolving Urban Boundary Object

Asphalt.  What could be more pedestrian, literally underfoot?  Or ignored as a dull gray ribbon somewhere beneath the floorboards as one navigates along city streets, concentrating on one's destination?  Or still more invisibly, as the cladding along the ditches keeping parking lots and pavement from flooding during rainstorms.

In reality, asphalt is a complex "boundary object" that points out how cities, suburbs, and exurbs are intricate social and ecological systems.  Asphalt as a boundary object links the consideration of social processes and ecological phenomena across the three-dimensional spatial mosaics of urban systems.  Furthermore, as those systems change, the role of asphalt as a boundary object can change through time as well.  

A recent paper by BES colleagues Geoff Buckley, Chris Boone, and Morgan Grove (2016) provides an excellent example of the changing role a boundary object may play, and it does so by elevating the virtually ubiquitous and nearly invisible substance of asphalt to our full attention. I recommend this paper not only for its scholarly rigor, but for the poetic imagery and narrative power it employs in bringing the roles and dynamics of asphalt to our attention.  This post is a teaser for that paper.

Contemporary urban residents would hardly recognize the streets of cities in the late 19th and early 20th centuries.  There was a time when city streets were paved with bricks, cobblestones, and even wood blocks if they were paved at all.  The expense and unstable footing for horses were points contributing to contentious civic discussion about these paving materials.  Buckley and colleagues show in detail how asphalt rose to primacy among a welter of available materials, economic considerations, and networks of political influence.  Asphalt achieved its familiar roles only after it had been argued for by automobile drivers, bicyclists, and those concerned with provision of mud-free school playgrounds.  

Franklin Square school yard, asphalt partially removed.

But as a multifaceted boundary object, the perceptions and actions focusing on asphalt have proven to be anything but permanent.  For example, as cities have shifted from the engineered "sanitary" focus of the last 150 or so years (Melosi 2000) to an emerging sustainability focus by looking toward a future that is jointly motivated by ecological, social, and economic integrity (Grove et al. 2016), so has the role of asphalt shifted.  Now, city policy makers and activists promote the removal of asphalt from school yards in an effort to reduce stormwater runoff and lessen the heat island effects around schools.  So too is asphalt reduced by replacement with pervious pavement, or by piercing the streetside with bioswales or rain gardens.  Over the century of the sanitary city and moving into the desired sustainable city century, asphalt has illustrated an integrative, but changing role in the social-ecological functioning of urban areas.

As a boundary object, asphalt focuses urban social-ecological researchers on the shifting networks of concern and changing understanding of what constitutes an amenity or disamenity among urban ecosystem structures.  The very factors of imperviousness and availability that led to the widespread adoption of asphalt ultimately contributed to its disavowal by environmentally conscious policy makers and by communities and agencies sensitive to social equity.  Have a look at Buckley et al's (2016) paper to understand this compelling history and its ecological implications more fully.

Steward Pickett, Director Emeritus

Literature Cited

Buckley, G. L., C. G. Boone, and J. Morgan Grove. 2016. The Greening of Baltimore’s Asphalt Schoolyards. Geographical Review:n/a-n/a. DOI: 10.1111/j.1931-0846.2016.12213.x

Grove, J. M., D. L. Childers, M. Galvin, S. Hines, T. Muñoz-Erickson, and E. S. Svendsen. 2016. Linking science and decision making to promote an ecology for the city: practices and opportunities. Ecosystem Health and Sustainability 2:n/a-n/a. DOI: 10.1002/ehs2.1239

Melosi, M. V. 2000. The Sanitary City: Environmental Services in Urban America from Colonial Times to the Present. University of Pittsburgh Press, Pittsburgh.

The Human Ecosystem: What's Missing?

The human ecosystem concept is one of the most common tools used in the Baltimore Ecosystem Study LTER.  Adopted from a team of social ecologists and sociologists who were involved in community forestry in the Himalayas, the application of such approaches to underserved areas in American cities, and the conservation and management of US National Parks, the concept is remarkably broad and adaptive.  The human ecosystem is not necessarily tuned to emphasizing the intellectual flavor of the week or most current headline issue for cities, urbanization, sustainability, or development.  However, its inclusiveness, nested hierarchical nature, and adaptability makes it well suited to dealing with shifting or even new emphases in social-ecological systems research and application (Figure 1). 

Figure 1.  The Human Ecosystem Framework
(Adapted from Machlis et al. 1997)

What are some of the hot topics that might seem to be missed in our discussions or presentations, but which in fact have a home in the human ecosystem framework?

Political ecology.  

This is at once a scholarly area and a subject of activist attention.  As a scholarly field, it examines the relationships of politics, economics, and environment.  As a social movement, it focuses on the inequitable distribution of benefits and costs of environmental decisions.  The social movement can be seen as a part of a larger social or environmental justice agenda. 

The multidimensional relationships with which political economy is concerned exercise several components of the human ecosystem framework.  Among the bioecological features, catalogued in the “ecosystems pattern and process foundations” component of the framework, many are relevant, including the distribution of energy, water, nutrient, and biomass resources, the kinds and levels of contaminants and pollution of air, water, and soil, and the heterogeneous or mosaic distribution of all of these factors.  Heterogeneity is important because control of access to resources, exposure to hazards, or distribution of benefits is subject to social – that is power and political – control.  Not all persons, groups, or institutions may be uniformly represented across a spatial mosaic.  The social control of access, exposure, and benefit engages many of the components of the human ecosystem framework.  The social ordering by factors of identity, rank hierarchies, and norms are key to the differential power relationships in human ecosystems.  Social rank hierarchy can further be broken down into ranks based on wealth, control of territory, social status, knowledge as a kind of capital, and, tellingly, power.  Among the social and cultural foundations, the distribution of populations, including by race, class, gender, or ethnicity, and the distribution of information by various institutions may reflect power relationships.  Of course the access to or participation in the institutions of sustenance, health, justice, education, etc. are also dependent on power relationships.  Other aspects of the human ecosystem framework (Figure 1) can also be used to investigate and explain, and therefore intervene in, power relationships in the urban social-ecological systems. 

Technology.  

Recently, our colleague N.B. Grimm has emphasized the fact that social-ecological systems have significant technological content.  Grimm at the 2013 Congress of Urban Ecology, the first such international meeting of the Society of Urban Ecology (SURE), introduced the term Social-Ecological Technical System, or SETS to emphasize the role of technology in how people think about urban ecosystems. 

This healthy reminder and highlight does no violence to the human ecosystem framework.  A classical representation of the significance of technology in human environment relationships is the POET model.  Under this general model, environmental change is said to be a function of human population, the way that humans are organized, and the technology available.  Explicit recognition of the role of technology in urban systems appears in the classical work of Borchert (1967), who notes that urban form in the United States shifted with the introduction of new technologies.  

Emphasizing transportation technology, Borchert proposed five epochs of American urban change: 1) sail and wagon (1790-1830), 2) steam powered ships and initial rail roads (1830-1870), 3) national steam rail network (1870-1920), 4) interstates and propeller air transport, and finally 5) satellites and jet propulsion.  American urban transformation continues, with other epochs hypothesized to represent the “slow growth” proposed in the 1970s of the oil embargo (Phillips and Brun 1978), or perhaps an epoch defined by the technology integrating global finance, manufacturing, and consumption.  In any event, the significance of technological innovation, change, and even retrenchment are clearly major components and drivers of urban change.  These latter technologies have a great deal to do with the current global teleconnections of urban systems with each other and with more rural and wild lands (Boone et al 2014).

Baltimore is a prime example of the role of shifting technologies.  For instance, the urban fabric of Baltimore, as described in Hayward and Belfoure (1999), shifted markedly with each transition -- from the walking city, through the city of horsedrawn trolleys, through the electric commuter rail, through the automobile era.  The industrial power of Baltimore similarly reflects major technological shifts, from the water power of the “fall line” through wood fueled steam, through coal powered manufacturing and steel production.  Other overlapping shifts, such as the opening up of the American South and Southwest with the availability of air conditioning technology there, and government policy for the location of defense industries away from the vulnerability of the east coast so feared during World War II, played a role in Baltimore’s post-industrial shift to a joint service, tourism, and knowledge footing.

In the Human Ecosystem Framework, technology appears foundationally in such things as the source of energy (e.g. water power, vs. wood, vs. coal), or the path of water flow (the location at the fall line between the Piedmont and the Coastal Plain).  Technology also is reflected in the amassing and deployment of labor, as in the contrast between slavery and voluntary immigration as sources, and the shift in capital investment in water-mill industry and canals versus the creation of America’s first long haul railroad – the Baltimore and Ohio.  

The technologies available and the pursuits different technologies make available have powerful influence on social identity, demographic structure, community and neighborhood cohesion and the like.  For example Baltimore still embraces a historical identity as a seafaring town.  This is shown by the fact that a waterfront neighborhood is still referred to as Canton, in honor of Baltimore’s fast clipper ships that cemented trade between China and the U.S. East Coast.  Or the fact that Fells Point, the location of Baltimore’s first deep water port, still retains the ameities and reputation as a freewheeling entertainment district reflecting its early tradition of hosting sailors on leave.  The coal-fired industrial era is honored in the Middle Class Mythology of Baltimore and its blue collar ethos.  These things are all features that find a home in the human ecosystem framework, for example in cultural myths, social identity, and temporal cycles of change in demography and institutional and organizational structures.

Infrastructure.  

Another hot topic these days is infrastructure.  Strictly speaking, infrastructure is what undergirds the various components of a system.  Infra means below.  It is the supporting structure, linkages, flows in any system.  The human ecosystem may seem to be blind to the built and engineered components of urban ecosystems.  This is because the human ecosystem framework assumes those physical foundations.  In 1997, we worked to refine understanding of the bioecological foundations of the human ecosystem.  The original discussions by Machlis and colleagues certainly included the bioecological and biophysical aspects of human ecosystems in the “resource system” component.  Perhaps because buildings, streets, supply pipes, electrical wires, railroads, sewers, storm drains, and so on are such conspicuous parts of urban ecosystems, we hardly felt the need to call attention to them.  Cities are so often defined based on density of built structures and of human inhabitants that pointing toward buildings and infrastructure could be tacitly assumed.

However, a later description of the human ecosystem as a model template showing major kinds of components and their connections attempted to make this assumption clear.  Cadenasso et al. (2006) is a good example of this integration of built – and hence infrastructural – components into general interactive and classificatory models of urban ecosystems (Figure 2).  There is nothing wrong with pointing to the various components of systems as infrastructure, but in a sense, that seems redundant with saying that an urban place is a human ecosystem comprising social, biotic, built, and physical (e.g. soil, topography, climate) components.  Infrastructure is just another word for components, really.  The big idea is that cities, suburbs, and exurbs are systems that contain many specific features and connections, and that those span and connect biology, physical environment, buildings, social processes and the myriad feedbacks among components.

Figure 2. A process model template of the human ecosystem.

A healthy outcome of the infrastructure label may be helping people to remember the often invisible biological components of cities, suburbs, and towns.  Infrastructure is now often spoken of as gray, blue, and green.  This division suggests that the complex system of the city or more broadly, the urban region, depends on services and structures provided by plants, animals, and microbes, and that these services emerge not only from partly or (almost) entirely engineered features, but also from parks, yards, street plantings, derelict field and lots, open streams, wetlands, and freeflowing atmosphere.  Planning, design, management, policy, and education will be better served, and will better serve the human population when the contributions of biological infrastructures and their components are understood and effectively employed.

Conclusion

The message here is that the human ecosystem framework (Figure 1), a hierarchical enumeration of the kinds of biophysical and social structures, resources, processes, and outcomes that make up not only cities and towns, but also wilderness and production landscapes, is adequate to include contemporary and important concerns of power, justice, technology, and infrastructure.  The human ecosystem framework can be considered a causal hierarchy, in which general causes or factors are broken down into more specific mechanisms and interactions.  Specific models of human (in general) and urban (in particular) ecosystem structure, function, and dynamics will draw upon several to many of the ideas and features included in the human ecosystem framework. 

The framework is complemented by a process model template (Figure 2).  This process model template emphasizes that urban systems are composed of biological components and their interactions, physical environments and their links, social structures and interactions, and built components and the interactions among them.  This model template emphasizes the comprehensiveness of kinds of components of cities, suburbs, and exurbs, as well as the interactions among the various components.

Thus, rather than neglecting important contemporary topics in social, engineering, historical, and political realms, urban ecology has frameworks and model templates that in fact can easily accommodate these features.  Technology is a part of the built environment, Power is an aspect of the social structures, and infrastructure is a way to group various built components, networks, and interactions.

References

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.

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Cadenasso, M. L., S. T. A. Pickett, and J. M. Grove. 2006. Dimensions of ecosystem complexity: heterogeneity, connectivity, and history. Ecological Complexity 3:1-12.

Hayward, M. E. and C. Belfoure. 1999. The Baltimore rowhouse. Princeton Architectural Press, New York.

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Phillips, P. D., and S. D. Brunn. 1978. Slow Growth: A New Epoch of American Metropolitan Evolution. Geographical Review 68:274–292.

BES Book of the Year, 2014-2015: Gottdiener and Hutchinson, The New Urban Sociology

The previous Book of the Year focused on bio-ecological theory.  Because BES is a social-ecological research and education endeavor, the Project Management Committee agreed that this year our book should focus on social theory.  An ideal book to help all of us in the project who are not social scientsts is Mark Gottdiener and Ray Hutchinson's book, The New Urban Sociology, 4^th Edition, published in 2010.  Some of us have profited by reading earlier editions of this book, which combines social processes and social heterogeneity thinking.  Hence, it is an excellent social mirror for our originally biological and geophysical spatial approach summarized by patch dynamics and the nested watershed concept.  They label their approach, “socio-spatial,” but those of you in the social sciences should not jump to the conclusion that this book is a resurrection of the discredited aspects of the Chicago School, or that it is an exercise in environmental determinism. 

Because BES is a social-ecological research and education project, the Project Management Committee agreed that this year should focus on social theory.

The book is written as a text book and therefore will be an accessible (but not condescending) introduction for biophysical scientists and educators in BES.  Hopefully, it will also provide fodder for our social science members to weigh in with their own insights and experience on the concepts, cases, and controversies the book discusses. 

The book comprises 14 Chapters that address the foundational theories in urban sociology and the contemporary issues and controversies about the topic.  The chapter titles are as follows:

1. The New Urban Sociology.  Including topics such as urban regions, megacities, and articulation of the socio-spatial approach.

2. The Origins of Urban Life.  The long history of urbanization through capitalist industrialization.

3. The Rise of Urban Sociology.  Here are the field’s founding giants, whose  theories continue to echo in current controversies and applications: Simmel, Wirth, the Chicago School and the rise of human ecology.

4. Contemporary Urban Sociology.  Theories and applications of political ecology, class conflict, capital accumulation, real estate, and urban culture.

5. Urbanization in the United States.  Our national urban history, through the rise of the post-war metropolis.

6. Suburbanization, Globalization, and the Emergence of the Urban Region.  This chapter includes deindustrialization, uneven development, suburbs and beyond, multi-nucleated regions.

7. People and Lifestyles in the Metropolis: Urban and Suburban Culture.  Class differentiation and space, gender, revitalization, and migration are topics.

8. Minority Settlement Patterns, Neighborhoods, and Communities.  Neighborhood dynamics, new forms of community, and interaction without proximity.

9. Metropolitan Problems: Racism, Poverty, Crime, Housing, and Fiscal Crisis.  The socio-spatial approach to social problems, income inequality, affordable housing, and service problems are additional topics beyond those in the subtitle of the chapter.

10. Urbanization in the Developed Nations.  This chapter compares and contrasts urban processes in Western and Eastern Europe and Japan vis a vis the US.

11. Globalization and Urbanization in the Developing World.  Changing perspectives on urbanization, the demographic transition, primate cities, shantytowns, and informal economies are discussed here.

12. Metropolitan Planning and Environmental Issues.  Sprawl, the sociology of land use planning, trends in planning are covered.

13. Metropolitan Social Policy.  Topics include the “tragedy of the commons,” uneven development, privitism, and social justice.

14. The Future of Urban Sociology.  Understanding the new urban world features here.

These topics are all helpful in understanding the social side of the Baltimore equation, as well as for understanding the national and international context in which Baltimore fits.  The changing nature of the global network of urban areas is a crucial ingredient in this understanding.

Each chapter ends with a list of key concepts, important names, and discussion questions.

The book is published in paperback by Westview Press.  The authors chose this publisher to be able to produce a book that was more affordable than the average university textbook.  You can order it from your local bookstore, or your favorite online source.  Used ones go for the mid 20 USD, and new for a little less than 50 USD.  It is also available as an e-book from some sources.  Those of you at colleges and universities might request that your library obtain a copy and put it on reserve.  The OCLC website – worldcat.org – can tell you whether local libraries have the book.

We will be planning a series of webinars to discuss various chapters or topics in the book.  If you want to be alerted to these, contact the BES Project Facilitator, Holly Beyar at beyarh at caryinstitute dot org.