Most urban ecology in cities remains an “ecology in cities” rather than an “ecology of cities.” Accomplishing the latter requires the inclusion of humans within the concept of “ecosystem,” both how humans alter the properties of urban ecosystems and how these alterations in turn influence human well-being. These influences are both direct (e.g., physiological and psychological influences on the human organism) and indirect, by influencing ecosystem sustainability.
For the 2007 ESA meeting, Larry Baker, Loren Byrne, Jason Walker, and Alex Felson organized a symposium to address the relationships among human choices and urban ecosystems. In the introductory talk of this symposium, these authors discussed how the cumulative effect of individual household choices can have major effects on the properties of urban ecosystems. For example, direct resource consumption by households accounts for 40% of U.S. energy use; in the Twin Cities of Minnesota, households account for 75–80% of total N and P inputs. Households also have a major impact on vegetation biodiversity in cities. Drawing from the social science literature, this first talk introduced the variety of conceptual models that have been put forth to understand how humans make choices. Economists use classic supply–demand models to understand consumption of market goods (such as energy) and other tools to understand the value of nonmarket goods. Environmental psychologists have often used the Theory of Planned Behavior and related models to explain barriers to adopting specific environmental practices. Political scientists focusing on group processes stress the process by which choices are made and the distributive effects of decisions. Although ecologists often focus on how human behaviors are environmentally destructive, there are also many examples of how collective choices have had very positive environmental outcomes. These include large declines in soil erosion and smaller declines in fertilizer P use by farmers in the United States, widespread adoption of household recycling, greatly reduced household water consumption in some water conservation programs, and rapid increases in the sales of the Prius hybrid automobile in recent years. Programs leading to these positive environmental choices generally include a mix of several of the following: a persistent, meaningful message; dissemination of accurate, trusted knowledge; early adoption by trusted individuals; financial incentives or disincentives; targeting of high-consumption individuals; direct regulations; personal economic benefit and feedback.
Three presenters examined factors regarding choices of managing the vegetation in urbanized landscapes. Morgan Grove from the Baltimore Ecosystem Study (BES-LTER) discussed an “ecology of prestige” in which consumption and expenditure on environmentally relevant goods and services are motivated by group identity and perceptions of social status associated with different lifestyles, and have used this theory to examine landscaping patterns. Grove and his colleagues combined high-resolution social and ecological spatial and temporal data such as property parcels and land cover (>1 m) with composite measures of population, social stratification, and lifestyle for this presentation. Fig. 1 shows the relationship between percentage tree canopy cover (height of bars) with PRIZM lifestyle classifications. Of particular interest in a long-term context is the relationship between cause and effect: the possibility that some social groups are attracted to and conserve existing, desirable landscapes at a neighborhood scale, while others move to and rehabilitate their landscapes.
Baker, L., A. Brazel, L. Byrne, A. Felson, M. Grove, K. Hill, K.C. Nelson, J. Walker, V. Shandas. 2007. "Effects of human choices on characteristics of urban ecosystems." Bulletin of the Ecological Society of America October: 404-409.