PhD Qualifying Exam: Area of Specialty (Question 5)

Researchers studying urban ecology have made the distinction between ecology in the city vs. ecology of the city. Do you consider this a useful distinction? In which of these areas would your proposed study fall?

Ecology is the study of biota and its biophysical environment. The field is young in comparison to its older sibling, Biology, which studies the behavior of species or cells. Ecology takes a step back to observe how species are interacting with each other and their habitat.

Ecology in Cities
In recent decades, a small group of rogue ecologists have chosen to practice ecology in urban environments. Roads, bridges, parking lots, abandoned mills, business districts and rail lines may sound like peculiar sites for ecological praxis. Yet these built environments have harnessed a devout following of urban ecologists, undeterred by rust, concrete, smog, or city sounds. These vanguard urban ecologists have generated a new sub-field in ecology that seeks to understand how species survive, behave, and reproduce in urban landscapes. They apply core principles from the natural sciences to study urban ecosystems and their practice can be understood as Ecology in Cities.

There are several good reasons why we need to understand species behavior in urban environments. In the summer, trees provide shade and reduce the heat island effect. They also are aesthetically pleasing, and if disease were to wipe them out, surly local residents would be upset about losing this amenity (and property values). Similarly, birds are great to hear in the morning, and squirrels are an entertaining feeding attraction.

The urban environment has also offered opportunities to test ecological theories. Landscape ecologists such as Forman and Mendelson have tested Wilson & MacAurthur’s theory of island biogeography. And the insight from landscape ecology provides practical guidance for urban ecosystem management. Urban ecologists have also observed how theories of adaptation and selection are reinforced. Pigeons are very successful urban species, and ecologists have found that they are related to bird species that previously inhabited cliffs. This partially explains why they have adapted well to cities, since tall buildings provide precisely the urban form/habitat they prefer.

Urban ecologists who practice Ecology in Cities are more likely to appreciate the impacts of humans on their study site, but there remains a degree of separation between the social and biophysical worlds. These urban ecologists still seek to understand the basic laws that govern urban species. Nature is still “out there” somewhere.

And yet the findings offered by this school of urban ecologists raises additional questions about the co-evolution of ecological and human species. In the pigeon example, human environments became the ideal habitat for a particular species. Humans in essence, helped the selection of pigeons over other bird species. Therefore in urban environments, and potentially elsewhere too, our ecological companions are products of human choices. If humans are the drivers of selection, then is it accurate to distinguish ecological systems from human systems? While not their intention, the urban ecologists that study Ecology in Cities
illustrated how species co-evolve with cities and human modified environments, and helped question the divide that they still respect.


Ecology of Cities
Social scientists from geography, environmental history and political ecology have blurred the nature vs human divide even further. Cronon deconstructed the concept of wilderness, and other geographers and political ecologists have followed suit by arguing that the no place on planet earth is unaffected by human influences. As such, “Nature is dead” (Castree).

This fusion of human and ecological systems into a singular unit of analysis gave birth to a form of Urban Ecology that studies the Ecology of Cities. Similar to how Ecology broke from Biology by broadening its scope of analysis, practitioners of Ecology of Cities took a step back even further by incorporating human systems as part of the socio-ecological environment. The city is studied as if were its own organism that consumes energy, materials, and water. The city has its own metabolism and excretes waste.

The Ecology of the City takes additional steps in breaking down the divisions between the human and biophysical environments by studying them in unison. This holistic approach is familiar to environmental historians. For example, in Grey Brechin’s historical account of urban growth in San Francisco he describes the flows of money, gold, and water that fed the growth of the City by the Bay. Even more eloquently, William Cronon observed how the agricultural and transportation pattern the Midwest, including the types of seed planted, was determined by the rise of Chicago.

The geographer Paul Robbins offers another example of Ecology of Cities in his study of the suburban lawn. Robbins boldly melds ecological and human systems by suggesting that the lawns themselves control human behavior. While his argument is counter-intuitive at first, he convincingly shows that the biological characteristics of turf grass, ie. the chemicals it needs and the cutting care it relies upon -- ultimately dictates how humans interact with the lawn and their neighborhood. The lawn calls out to be mowed. And people respond, dutifully mowing their lawns on weekends in the late Spring, precisely when the lawn wants to be trimmed.

Ecology in Cities & Ecology of Cities
The distinction between the Ecology in Cities and the Ecology of Cities is useful because it helps break down disciplinary barriers. It is a step toward integration and a movement away from reductionism. The Ecology of Cities adds intriguing complexity to our analysis of urban ecosystems and helps us see that biophysical systems are not independent from historical decisions, human choices or cultural perceptions.

Appreciating this distinction is especially important in an era of interdisciplinarity and sustainability. Everywhere there are calls for improved integration across fields. There is strong impulse to generate new understanding by overlapping and combining knowledge from different arenas. There is a pressure to be more integrative and holistic.

This call for integration and appreciation of the integral role of humans in ecosystems has been well received by some conservation biologists (Armsworth et al. 2007). They are starting to recognize that it is time to include humans into their analysis of ecosystems. For too long conservation biology has focused narrowly on their favorite species or ecosystem and only referred to humans in passing, or as the source of destruction. Armsworth et al (2007) suggested that conservation biologists incorporate humans into the ecosystem, and therefore make the move from Ecology in Cities to Ecology of Cities.

And while most agree that the synthesis proposed by practitioners of Ecology of Cities is valuable, I am humbled by the implications of this daunting task. Meaningful integration of human and biophysical systems is an enormous undertaking. The assumption is that it will provide more clarity into the phenomenon observed. However more clarity is not guaranteed. While I agree that this integration is useful and necessary, I am wary of how it will materialize.

To appreciate the complexity implicit with this integration, we can look to the difficulties ecologists have encountered when combining physical and ecological models. These difficulties persist despite the rigidity of the physical laws and relationships more common in the physical sciences.

Carl Walters from the University of British Columbia has studied ecological modeling and adaptive management in coastal and river ecosystems and he provides an excellent review of the difficulties associated with modeling the biophysical world. He points out that river manager’s need four types of models to understand river systems: a geomorphologic model, a hydrological model, a physical-chemical model for water quality, and an ecological model. Each model operates different time and spatial scales, with different resolutions, units of analysis and degrees of uncertainty. Adding new parameters often leads to compounding errors multiplicatively, and therefore decreasing the utility of the model. Thus Walters is skeptical that these models can be meaningfully integrated without field experimentation. He warns that researchers trust their models too much, and they are over ambitious in what they think they can achieve. Walters laments that for every complex relationship that is nearly impossible to explain, there is a researcher who will claim the capacity to model the relationship if only granted enough money. Walter’s observations about the difficulty in combining different biophysical models is useful warning for interdisciplinary graduate students who may underestimate the difficulty in integrating knowledges from the biophysical world with the social sciences.

Where does my research fall?
I will draw from the knowledge generated by both types of Urban Ecologists, but the direction I will pursue follows the spirit of those who study the Ecology of the City. My dissertation will have at least two components. I expect to begin with an environmental history of salt pollution in the Llobregat River. Similar to Cronon, Brechin and White, this segment will follow the tradition of urban ecologists concerned with the ecology of the city. The environmental history will trace the evolution of potassium mining, pollution and the urban settlements near the Llobregat side by side. I seek to uncover how people shaped the river, but also how the river shaped human choices and perceptions in the past and today.

Following the environmental history, my dissertation will study how the management of ecosystem services may help river and water treatment managers seeking to remediate river pollution. The particular circumstances in the Llobregat River, whereby salt pollution in the river increases water treatment costs, provide a convenient link between the biophysical and human systems. This part of my research will reflect more similarities to the research of Ecology of Cities since it bridges both human and ecological systems.

Research concerning ecosystem services seeks to break down barriers between social and biophysical sciences and to make the connections between these systems more explicit. In this sense, research on ecosystem services is consistent with the Ecology of Cities approach. And yet, the field of ecosystem services has chosen to push together the human and ecological systems very close, but refused to mesh them together entirely. After all, most researchers in ecosystem services were trained in the biological of physical sciences. These researchers are grounded in a distinct philosophical and epistemological tradition that makes it very difficult for them to accept all of the claims made by political ecologists who advance the study of urban systems as one single system. Furthermore, the methods and tools used in ecosystem service science resemble those from their peers, traditional Ecologists, who study Ecology in Cities.

Therefore researchers in ecosystem services resist wiping away all distinctions between natural and human worlds as some political ecologists have proposed. Researchers in ecosystems services are unlikely to give non-human things agency, nor are they likely to believe that “Nature is Dead”. In many respects they are holding on to the differences between the two fields. Researchers of ecosystem services are therefore an interesting amalgam of both urban ecololgists, that drawn on the tools from Ecology in the City, yet seek to advance the cause of those who subscribe to studying Ecology of the City.

In sum, the distinction between Ecology in Cities and Ecology of Cities is useful because it shows different levels of integration between human and ecological systems. Placing my work on environmental history and ecosystem services within this continuum clarifies how I will contribute to Urban Ecology. It shows that while my tendency is to advance the integration proposed by study of Ecology of Cities, there are still limits to this integration. These limits to integration are driven by both technical challenges in creating meaningful understandings that cross disciplinary boundaries, as well as by philosophical and epistemological beliefs about how to conduct research, and the extent to which the biophysical world is a human construct.