Culture and Ecology of Chaco Canyon and the San Juan Basin

A Broader Perspective 339whom fall between the fourth threshold and the lastthreshold, suggested to Binford that similar kinds ofdensity-dependent changes affected each of thesedifferent societies.A. Johnson's Southwestern HorliculturalistsPueblo horticulturalists were studied by A.Johnson (1997), whose goal was to determine why thepace of the adoption of horticulture and the process ofvillage formation vary across the Southwest. Becausethe environment has changed very little over the past4,500 years, the Southwest offered an opportunity toexamine the transition to food production. At thisregional scale, Johnson examined 25 Pueblo and 15non-Pueblo ethnographic cases. The initial conditionsthat formed the basis for explaining the pace andprocess of the development of food-producing strategiesand village formation were subsistence, mobility,population density, and group size.Based on permanent settlements, surface treatmenton ceramics, and aspects of house forms,adaptive strategies for each of the cases were classifiedinto three adaptive phases:Phase I represents the span of time betweenevidence of the earliest maize and the initial appearanceof early pottery and round houses. Huntinggatheringis the primary subsistence strategy. In thisphase, cultigens were considered seasonal supplementsto the gathering of wild resources, which is differentfrom the adoption of horticulture. Sites with theearliest maize are located in contexts of relativelystable hunter-gatherer groups. At the end of phase I,plain pottery, more permanent sites, and an increasedreliance on cUltigens occur.Phase II covers the span of time from the appearanceof plain pottery to the construction of siteswith up to 100 rooms, integrative features, andtextured and painted pottery. This period was indicativeof a horticultural adaptation, which is a subsistencespecialization around which other activities ofthe group are organized. This strategy appears in theleast stable hunter-gatherer areas. Organization of thehorticultural strategy will vary with aspects of thelocal environment.Phase III begins with the appearance of large(more than 100 rooms), aggregated sites with communalarchitecture represented by large integrativefeatures and massive labor investment. Agriculture,or farming, as the chief subsistence pursuit, providedsubsistence needs. The earliest population aggregationsand evidence for a permanent, stable aggregatedcommunity are found in different environments.Aggregation responds to labor needs that are found inareas with tbe lowest subsistence diversity. Foodproduction responds to mobility options in areas withhigher subsistence diversity.Throughout the Southwest, horticulturalsites are located in environments wherehunter-gatherer subsistence options wouldhave been least diverse, and least stable.Under conditions of population packing,labor investment in horticulture wouldhave been the only intensification option inthe Southwest, where aquatic resources arenegligible. In areas where hunter-gatherersubsistence diversity is expected to be low,any reduction in mobility options associatedwith population packing could lead toa critical reduction in subsistence options,forcing greater reliance on a much narrowerrange of resources. Investment inhorticultural strategies could mitigate therisk of relying on such a narrow range ofwild resources in a number of ways. First,it could increase the utility, from thestandpoint of humans, of primary productivity-e.g.,grasses with large seeds aremore useful than shrubs or grasses withsmall seeds. Second, it could increase thepredictability of both the timing and theamount of resources available. Finally,increased labor investment in fertilizing,watering, and weeding, could increaseyields beyond the productivity of thenatural vegetation. While the distinctionbetween non-horticultural and horticulturalsite locations follows the niche breadthgeneralization throughout the study area, itis expected that the organization ofhorticultural strategies will vary dependingon which aspects of local environments