Urban ecology (Encyclopedia of Environmental Issues, Revised Edition)
In the 1920’s sociologists Robert E. Park and Ernest Burgess developed a theory of urban ecology that postulates that cities are environments similar to those found in nature, regulated by principles analogous to those that govern nature and natural evolution. This theory views the overall structure of cities as the consequence of the struggle for limited urban land, which influences cities to evolve gradually into five concentric rings. The term “urban ecology” also refers generally to that part of the science of ecology that studies the interactions among human beings, plants, and animals within urban and metropolitan areas, as well as the effects that urban development has on natural ecosystems and on biodiversity in these areas.
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Importance of Biodiversity (Encyclopedia of Environmental Issues, Revised Edition)
High levels of biodiversity (genetic, species, and habitat diversity) are important not only for plant and animal species but also for the quality of life of human beings. The higher the level of biodiversity in an ecosystem, the better able the ecosystem is to face instability, whether of natural or anthropogenic (human-caused) origin.
In regard to biodiversity, human-nature interactions in urban and metropolitan areas face two challenges. First, the rapid and increasing pressure that will result from foreseeable demographic growth is likely to have substantial negative impacts on biodiversity. The United Nations estimates that in 2050 the world population will reach 9.1 billion, most living in urban areas; this trend will substantially increase the human pressure on natural ecosystems. Second, climate change, although still uncertain in its extent, requires adaptation and mitigation measures in urban and metropolitan areas that will increase the resilience of urban ecosystems. On the other side, changes in land cover affect the stocks of carbon, and through that effect these changes are also expected to have impacts on climate. For this reason, changes in land cover owing to anthropogenic factors constitute another facet of urban ecology that needs to become a central issue in urban planning.
(The entire section is 198 words.)
Changes in Urban Planning (Encyclopedia of Environmental Issues, Revised Edition)
During most of the twentieth century the environment was not a central theme in urban planning, and most planners did not develop urban biodiversity strategies. Since the 1970’s, however, protection of the environment has gradually become a key component of urban planning. Urban green spaces and green corridors are important elements in the urban planning paradigm, known as the new urbanism, that developed in part as a reaction against modern urbanism. Urban ecology also gradually became part of the core disciplines that constitute the multidisciplinary field of urban planning.
In addition to conducting biodiversity inventories (such as inventories of native plants in risk of extinction in specific urban areas), urban ecologists examine the impacts of urbanization on native species of plants and animals (both vertebrates and invertebrates) and on wildlife in general (including reptiles, aquatic vegetation, and native fish). They also evaluate the effects of streets, roads, and other urban infrastructures on plant and animal species.
The study of the urban ecologist ends, in most cases, in policy recommendations in the form of an urban biodiversity strategy, as part of a wider urban planning process. These policy recommendations address different types of actions, both direct and indirect. An urban biodiversity strategy may suggest, for example, that a city or metropolitan area create habitats or restore...
(The entire section is 327 words.)
Further Reading (Encyclopedia of Environmental Issues, Revised Edition)
Goudie, Andrew. The Human Impact on the Natural Environment: Past, Present, and Future. 6th ed. Malden, Mass.: Blackwell, 2006.
McDonnell, Mark J., Amy K. Hahs, and Jürgen Breuste, eds. Ecology of Cities and Towns: A Comparative Approach. New York: Cambridge University Press, 2009.
Marzluff, John M., et al., eds. Urban Ecology: An International Perspective on the Interaction Between Humans and Nature. New York: Springer, 2008.
Raven, Peter H., and Linda R. Berg. Environment. 5th ed. New York: John Wiley & Sons, 2006.
Selman, Paul. Local Sustainability: Managing and Planning Ecologically Sound Places. London: Paul Chapman, 1996.
(The entire section is 92 words.)