We generated five general principles to satisfy these intellectual and practical requirements (Table 1).
- Cities are ecosystems.
- Cities are spatially heterogeneous.
- Cities are dynamic.
- Human and natural processes interact in cities.
- Ecological processes are still at work in cities.
What’s a Principle, Anyway?
|Research and management in vacant lots (photo: C. Swan)|
- Cities and urban areas are human ecosystems in which social-economic and ecological processes feed back to one another.
- Urban areas contain remnant or newly emerging vegetated and stream patches that exhibit ecological functions.
- Urban flora and fauna are diverse, and this diversity has multiple dimensions (e.g. taxonomy, cladistics, function, geographic origin).
- Human values and perceptions are a key link mediating the feedbacks between social and ecological components of human ecosystems.
- Ecological processes are differentially distributed across the metropolis and the limitation of services and excess of hazards is often associated with the location of human communities that are poor, discriminated against, or otherwise disempowered.
- Urban form is heterogeneous on many scales, and fine-scale heterogeneity is especially notable in cities and older suburbs.
- Urban form reflects planning, incidental, and indirect effects of social and environmental decisions.
- Urban form is a dynamic phenomenon and exhibits contrasts through time and across regions that express different cultural and economic contexts of urbanization.
- Urban designs and development projects at various scales can be treated as experiments, and used to expose the ecological effects of different design and management strategies.
- Definition of the boundaries and content of an urban system model is set by the researchers based on their research questions or the spatial scope of its intended application.
- Urban comparisons can be framed as linear transects or as abstract gradients, and the abstract comparisons acknowledge the spatial complexity of urban heterogeneity.
- Urban land covers and land uses extend into and interdigitate with rural or wild land covers and uses.
- The flux of water, including both clean water supply and stormwater management, is of concern to urban and urbanizing areas worldwide, and connects them explicitly to larger regions.
What do Principles Do?
- Identify the main concerns of a theory.
- Serve to link general and specific components of theory.
- Lay out expectations of mechanism or interaction.
- Summarize patterns of interest to the theory.
How are Principles Arrived At?
|Thirteen ways of looking at urban ecology (apologies to Wallace Stevens), arranged as a nested conceptual hierarchy.|
Ecology/Ecologies: One Science, Many Models