Urban Ecology

Ecology is a branch of biology that studies relationships between and among organisms and their environment. When the environment under study is located in a city, the subfield is called urban ecology. A city is larger than a small town. However, definitions vary as to what minimum population is required to constitute an urban environment. The U.S. Census Bureau requires a population of at least 2,500 to be considered an urban location.

The urban ecology scale of analysis can be a small patch of land within a city, an urban area determined by city boundaries, an urban area determined by settlement boundaries, or a region containing several cities. Sometimes the urban extent of settlement is under- or overbounded by the city limits, making it difficult to use political boundaries to study naturally bounded ecosystems. To solve this problem, some scholars suggest using watershed or alluvial basin as the appropriate naturally bounded unit of study, including one or more urban areas and all of the adjoining agricultural and natural landscapes within them.

Urban ecology is important and useful because it provides a bridge between urban environmental research and the more practical aspects of urban land use planning. Even though cities constitute only a small percentage of the surface of the earth, the anthropogenic impacts are profound—pollution, fragmentation or elimination of habitat, and climate modification, to name a few. With the goal of solving some of the problems associated with urbanization, urban ecology practitioners hope to achieve an efficient and equitable management of resources to improve the quality of life of city residents.

The meaning and methodology of urban ecology among scholars, practitioners, and the general public have evolved significantly over time. Ecology has its roots among naturalists of the 19th century and was not applied to cities until the 1920s and 1930s. Scholars at the University of Nebraska and the University of Chicago sought to use concepts and methods of plant and animal ecology for the explanation of human spatial patterns and changes over time in rapidly growing cities of early-20th-century America. For example, concepts of distribution and growth of animal communities were applied to the distribution of crime and disease and the subsequent spread of these blights in city neighborhoods. Popular among sociologists, economists, and geographers, this emerging subfield was first called human ecology and was not called urban ecology until several decades later. Social scientists of the 1940s criticized this biological approach to studying human populations and began to emphasize the importance of culture and social context. Mapping of urban socioeconomic characteristics was used to develop the earliest urban models that described the ideal city in terms of zones of wealth and poverty as well as areas of concentration[Page 514] and segregation of several generalized socioeconomic groups.

Environmental social movements and resultant legislation of the 1970s propelled research, grassroots involvement, and government mandates to build environmentally healthy and sustainable cities. Rapidly growing cities, increasing urban sociological problems, and ever worsening urban environmental pollution drew the attention of ecologists. Social scientists shifted from past methods of looking only at the socioeconomic variables of city life to considering the environmental concerns of urban sustainability. Issues such as clean water, clean air, waste management, infrastructure development impacts, and interactions with the nonhuman natural environment were of urgent interest. In response, many towns, cities, and states formed governmental and nongovernmental organizations (NGOs) to better understand and promote urban ecology.

...