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Global Roundtable - The Nature of Cities

posted Dec 5, 2014, 10:13 AM by James Steenberg   [ updated Jan 4, 2015, 6:43 PM ]
The following is my contribution to a Global Roundtable discussion on the Nature of Cities forum. The Roundtables bring together groups of international authors around a central question. The original posting, and contributions by the 11 other authors can be found here:

How can different ways of knowing—and of producing knowledge—be useful for understanding and managing urban ecosystems?

My current work has me reflecting on models – ecosystem models, that is – and their role in understanding nature in the city. From my viewpoint, anytime an environment, or a system, or a concept, is described in anything but its entirety it becomes a model. This could be through narrative, spatial representation, or ecosystem modelling.

As both researchers and practitioners of and/or in urban ecosystems, we often undertake some form of assumption, abstraction, and aggregation of the real world. We construct a model and therefore omit knowledge. Arguably, the hope is that what has been left behind, whether for the sake of parsimony, practicality, or functionality, does not compromise the model’s utility in describing the ecosystem. This hope is then dependent on what is defined as an ecosystem.

Theoretical discussions on the ecosystem concept no longer view ecosystems as deterministic, stable, or within closed boundaries. They are adaptive, and both scale and context dependent. Importantly, current urban ecological theory now envisions human activities as internal processes that shape ecosystem structure and function, rather than external agents of change and disturbance.

In my own research, I have been attempting to bring this modern urban ecosystem concept from the theoretical to the applied realm. I’m developing a framework for identifying and classifying urban forest ecosystems using quantifiable and spatially explicit variables that represent (i.e., model) their biophysical landscape, built environment, and human population. Ecosystem classification is a form of modelling that attempts to answer the following questions for researchers and practitioners: What does an ecosystem look like? What happened to make it look that way? What will it look like in the future? In such a fashion can they hope to intervene and manage urban ecosystems towards a more desirable state.

However, in the process of ecosystem classification we knowingly ascribe categorical characteristics to continuous phenomena and draw sharp edges around soft boundaries. This latter issue has been long recognized as a caveat of classifying landscapes – as ecosystems or otherwise. Yet, ecosystem classification has still been recognized as a useful tool for modelling and managing complex systems in its hinterland applications where the emphasis is primarily on biophysical ecosystem components.

In the urban landscape, where the influence of densely-settled human populations and their social structures and institutions on ecosystem processes are so evident, can ecosystem classification still maintain its utility? Can it be adapted to account for these theoretical advancements in urban ecology and the ecosystem concept?

These are my research questions, though I will admit to feeling apprehensive in shifting from the theoretical to the applied. Specifically, the quantification and classification of the ‘human component’ of urban ecosystems is fraught with challenges. For example, ecosystem classification is, in part, a statistical endeavour. As illustrated above, people at that tail end of that distribution curve who occupy the space outside two standard deviations will be the most dissimilar ecosystem components. In urban forest management, this population may be at risk of marginalization – or perhaps equally likely, may be a disproportionally vocal and influential subset of the population and ecosystem. In the context of building ecosystem models, is the omission of social knowledge as acceptable as that of ecological knowledge?

As a researcher, I’m as fascinated by the flaws of ecosystem classification as I am by the possible applications. I do think that applying ecosystem classification in strategic urban forest planning and management can be a valuable way of knowing and of producing knowledge about these ecosystems. Rather, I think this dialogue is the result of examining social processes from my own physical sciences perspective, and thus emphasizing the absolute necessity of inter- and transdisciplinarity within the research and management of urban ecosystems.