Culture and Ecology of Chaco Canyon and the San Juan Basin

Environment and Natural Resources 59similar, the survival rate and size of the cobs weremuch different. With watering, some improvementwas noted, but adequate natural precipitation wasneeded. The regime or scheduling of this precipitationwas also critical, especially during the months ofMarch through August. Even in the plot located alongan irrigation ditch, the water flowing through the ditchcame too late in the season to be of use. Theseresearchers concluded that Chaco definitely was amarginal environment for growing com; even inproven locations, farming was risky. The effects ofeven small changes in rainfall on plant and animaldensities during recent times as recorded by Potter andKelley (1980: 103), Scott (1980), and A. Cully andCully (1985b), and discussed above, are similar tothose reported by H. Toll et al. (1985).Yet environmental factors alone cannot beconsidered sufficient to explain human behavior.Dean (1984, 1988, 1992; Dean et al. 1985, 1994) andhis colleagues have been investigating the interrelationshipsof environmental, population, and behavioralvariables in the archaeological record from a regionalperspective. On the southern Colorado plateaus ofArizona, they studied low- and high-frequencyenvironmental variability and attempted to evaluatehuman responses (mobility, shift in settlement, subsistencemix, exchange, ceremonialism, agriculturalintensification, and territoriality).No longer can a single measure ofenvironmental variability, such as rainfallbe involved to "explain" behavioralchange. It is essential that both high andlow frequency processes be documentedand that their interaction with one anotherbe understood. In addition, the behavioralimplications of temporal and spatial environmentalvariability must be accountedfor in understanding adaptive processes.Finally, because so many environmental,behavioral, and demographic variablesinteract in different ,vays to producedifferent adaptive systems, each periodunder investigation is likely to be unique.Generalization, therefore, is difficult.Clearly, retrodicting past environments insufficient detail to understand the culturenatureinteraction is an extraordinarilydifficult task. (Dean et aI. 1985:550)In conclusion, although we have learned muchabout the environment and natural resources, there ismuch work to be done before we can explicitly modelhuman adaptations to the Chaco area. The followingchapters incorporate data and models available duringthe Chaco Project and comment on new informationavailable since that time.