Urban Ecology

It has become a truismdalmost a clichédto note that humans are now a predominantly urban species. This simple fact elides the substantial implications that an urban future has for humans and nonhumans alike. In the opening decades of the 21st Century, the Earth has becomedin many waysda planet of cities. Cities range in size from tens of thousands to tens of millions of inhabitants; they vary in form and in functiondas centers for commerce and employment, places of education and cultural exchange and of course, they provide housing for people, recreational opportunities, and livelihoods. Cities also traverse biomes, soil types, climatic zones, topographic features, and territorial boundaries; they extract and exchange resources from hinterlands (tributary regions) that extend well beyond their metropolitan areas. The hinterlands of some megacities, with metropolitan populations of more than 10 million inhabitants, can span thousands of kilometers, and we are now seeing the dawn of “hypercities” with populations of 40 million or more (e.g., the Jingjinji Metropolitan Region in China, comprised of Beijing, Tianjing, and Hebei cities). Yet these sorts of labels mask the heterogeneity and complexity of settlements. Cities are places of lifedand death, renewal and decay, flourishing, and extinction.

Cities consume vast quantities of energy, contribute to carbon pollution and climate change, generate a bewildering range of wastes, and alter the biogeochemical cycles of local, regional, and increasingly global environments. The future of human and nonhuman life is inextricably tied up in the urban condition. Core tasks for geographers include: better understanding how materials and energy circulate through the fabric of built environments; how urban spaces are created through diverse labor relations, processes of exchange, and the machinations of global capitalism; how life chances are unevenly distributed through urban space; and how different species inhabit the urban environment and navigate urban lifespaces. Of particular interest is how discourses of the urban are produced and circulate and the work they perform. Surrounded by everyday natures in the citydweeds, cockroaches, ratsdand by remnant vegetation and animals that cling tenaciously to the scraps of former biomes, we can become blind to the throng of living things that share our cities. Moreover, we tend to fetishize the terrestrial in cities, forgetting about the aquatic, atmospheric and subterranean spaces that comprise urban worlds.

Despite their particularities, or perhaps because of them, cities of both the industrialized north and developing south have become an interconnected global urban socionatural system of genetic, chemical, material, information, and energy exchange. Humans and nature are now fused in networks of relations. Commentators increasingly see socioecological relations as indicative of a new geological epoch termed the Anthropocenedan epoch now challenging the Western Enlightenment schism between people and nature. As undeniably socioecological entitiesdsimultaneously natural and culturaldcities challenge our ideas about the natural world. In cities, humans and nonhumans appropriate, metabolize, and transform “natural” environments, reconstituting them through the application of technology and labordcreating buildings, roads, urban forests, stormwater systems, and gardens as well as dens, dams, nests, humus, and hives (among other things). Mirroring this increasingly metabolic understanding of cities are changes within the burgeoning of a field of scholarship termed urban ecology.