For the city planners of ancient Greece, successful city-states were those that not only provided an economic and cultural base for its citizens, but could also be covered on foot in a day. Each city-state contained an acropolis, or high city, atop a hill, and a marketplace surrounded by homes and farms at the base of the hill. Those early planners could never have dreamed that Athens would someday become one of the most congested cities in the world. Needless to say, times have changed. Phoenix isn't the first city to grapple with the issue of explosive growth and some of its negative impacts-- congestion, pollution and the destruction of natural habitats. But Phoenix is unique among the major cities of the world. It is young and it is located in the desert, adjacent to undisturbed, biotically rich areas of the Sonoran Desert. This makes it an ideal subject for the study of the effects of urbanization on the environment.

A long-term urban ecology study of the Phoenix metropolitan area (as well as at other sites around the country) is presently underway, thanks to a grant received by Arizona State University from the National Science Foundation. This study, known as Long-Term Ecological Research (or LTER), will be directed by ASU's Center for Environmental Studies, but will involve professionals from many disciplines and coordinate data from a wide range of projects. To date, little research has been conducted on urban ecosystems. Yet, as more people have migrated from rural to urban areas in this century and cities encroach on undisturbed natural environments and prime agricultural land, the need for such research has become critical. Quality of life issues for urban and suburban residents also deem it necessary. It is hoped that the information garnered from this broad study will become an important tool for planning more ecologically sound urban environments in the future.

One of the major areas the research will focus on is the study of plant growth patterns at various land-use sites in the region. This portion of the study will help establish how these growth patterns are altered as land-use changes take effect. GIS data gathered from satellite and aerial imagery will be used to map vegetation types and density for the entire region. Tree productivity will be measured at specific sites via coring of native and non-native species. This procedure is an effective tool for monitoring long-term climatic conditions at a given site. The growth pattern of grasses and shrubs in suburban yards will also be assessed. Plant water-use efficiency experiments that measure carbon dioxide uptake and evapo-transpiration will be conducted on two kinds of sites: native remnant sites of creosote and cactus, and turf areas in urban greenbelts. In addition, surveys of mycorrhizae, root fungi that form a mutually beneficial symbiotic relationship with plants, will help determine the effect of human disturbance on their populations, and thus plant growth, in the greater Phoenix area.

Human impact on populations of various organisms will also be monitored. Four species groups have been selected: humans, arthropods, birds and plants. A survey of native and cultivated species in the region (essentially a "Flora of Phoenix") will reveal long-term changes in plant communities due to urbanization when it is compared with a similar census conducted 20 to 30 years ago. Similarly, lichenologists will monitor lichen communities to detect changes in air quality over time. Bird populations will be surveyed with the aid of state agencies and The Audubon Society. This portion of the study will also seek clues as to how ecological diversity is maintained in remnant native sites along urban, desert and agricultural boundaries. A comparison of species composition and richness in recently isolated sites will be made with previously isolated sites.

Other areas of research include organic matter accumulation and movement of nutrients through ecosystems, particularly nitrate accumulation in groundwater and salinization of soils and aquifers. To help predict and plan for future changes, land-use studies that incorporate demographic and socioeconomic data will also be implemented. An outreach education program for grades K-12 will allow student participation in the study. The CAP- (Central Arizona Phoenix) LTER database will incorporate student-acquired data in areas such as monitoring of bird and insect populations and air and water quality testing.

For further information on this study, you can visit its website at: caplter.asu.edu