Central Arizona-Phoenix LTER

Figure 1. Annual changes in amount and location of residential fringe development from 1990-1998. Growth at the fringe occurs in waves of new housing development that influence microclimatology, runoff patterns, and ecological processes (Gober et al. 1998).

Landmark Nitrogen-balance project provides guidance for city management at CAP LTER

Anthropogenic sources far outstrip natural sources of N in the nitrogen mass-balance of the CAP ecosystem. More interestingly, the vegetation and soils in the city are likely sinks for retaining much of the enormous production of N from combustion-derived NOx production (Baker et al. 2001). Such information can be used to help guide responsible use of commercial fertilizers by accounting for the use of high-nitrate content groundwater for irrigation.

Modeling Metropolitan Growth

A study of the growth of the Phoenix metropolitan area, determined that the spread of the city through the construction of new single-family houses at the periphery could be characterized by a "wave of advance" model (Fig. 1; Gober et al. 1998). Related studies are showing that this wave is instrumental in determining changes in key ecological variables such as microclimate, soils, and vegetation cover. The initial data for this came from county records but is now being supplemented by CAP LTER researchers who are using sequences of aerial photos to monitor land-use change in greater detail. At the same time our remote sensing team is developing a classification scheme to carry this study forward into the future in a more time efficient and comprehensive manner.

Environmental Injustice in the Phoenix metro area

A third key study has looked at whether there is a systematic relationship between the distribution of environmental hazards and location of minority and/or economically disadvantaged residential groups. Examining both sources of toxic releases and patterning of air pollution, it is clear that ethnic minorities and the poor are exposed to greater environmental hazards (Fig. 2; Bolin et al. 2000). As the pattern of industry changes, however, this correlation may change as well. With the shift from traditional smokestack polluters to new economy chip manufacturers comes a greater tendency for polluters to be located in more affluent neighborhoods. Part of our study is looking at how local residents perceive these risks and the type of action they take to ameliorate the situation.

Figure 2. Map illustrating the co-association of social patterns with perceived and real environmental risks of toxic releases. (Bolin et al. 2000).