ABSTRACT

In recent years an area of study and concern has emerged from the traditionally separate areas of “urban” and “ecology.” Previously, most “urban” studies tended to concentrate on the social and ignore the ecology of the city, although the Chicago School of the 1920s did employ biological terms such as invasion and succession in their understanding of the city, and this strain of social ecology did remain. However, the terms became metaphors, more analogies than fully theorized concepts. Most of traditional “ecology” in turn tended to focus on the less urbanized areas. The science of ecology developed out of a primary concern to understand “natural” processes. The emphasis was on ecosystems with minimal human connections. The early models were developed with primary reference to pristine ecosystems. Between 1995 and 2000, of the 6,157 papers in the nine leading ecological journals, only 25 (0.2%) dealt with cities. A new urban ecology has emerged that considers cities as sites of biophysical processes interwoven with social processes in complex webs of human—environmental relations. We will use the term urban ecology to refer to the ecology of cities rather than simply the study of ecology in cities. Specific journals such as International Journal of Urban Sustainable Development, Urban Ecosystems and Urban Ecology publish a wide variety of papers in this new and exciting field. Researchers in urban ecology are developing both general models and specific case studies. From the rapidly growing and rich body of work, here are just three examples. Mary Cadenasso and her colleagues, for example, theorize the Baltimore metro area as a complex of biophysical, social and built components. They apply standard ecological approaches such as ecosystem, watershed and patch dynamics in order to answer three general questions: What is the overall structure of the urban ecosystem? What are the fluxes of energy, matter, population and capital in the system? What is the nature of the feedback between ecological information and environmental quality? 1 In a more specific vein, Milan Shrestha and colleagues show how rapid urbanization affects spatio-temporal patterns of land fragmentation in the Phoenix metropolitan area. 2 Nikos Georgi and K. Zafiriadis look at the impact of trees in parks on urban microclimates. They show, with reference to Thessalonica in Greece, that trees reduce summer temperatures, increase relative humidity and have a general cooling effect. 3