Although population growth rates may have been low initially, populations nevertheless did grow over time, and high-elevation foragers began to move into new niches and use ones occupied earlier in different ways. In the Andes, this process can be seen primarily through the lens of the relative degree of mobility of these foragers. Obviously, mobility and land-use patterns were tempered by local resource configurations as well as regional-scale climatic changes. The middle Holocene (6400-3800 BC) was characterized by a trend of increasing, sometimes severe, aridity. In the salt puna of northern Chile and northwestern Argentina, for example, Nunez (1983) has long argued for a so-called “silencio arqueologico,” wherein much of the Andean highlands were abandoned for much of the period. Although more recent research has refined his concept both regionally and temporally (Aldenderfer 1988; Nunez, Grosjean, and Cartajena 2002), it is clear that the foragers of that region were tethered to water and moved frequently between resource patches as they were exhausted. In the circum-Titicaca region during this period, precipitation is estimated to have been only 40% of that seen today, and Lake Titicaca fell from between 50 to 100 m below its modern level. Its waters would have approached one-half the level of salinity of sea water. However, this was interrupted by sharp, but brief, rises in lake level (Cross et al. 2001). This suggests that resource predictability and certainly productivity would have been highly variable in the basin. In contrast, the Junin puna, while certainly drier than in modern times, saw precipitation remain
More constant, and therefore, primary productivity would have been more consistent on an annual basis (Seltzer et al. 2000).
This variability is reflected in clear differences in settlement patterns between the two regions. In the Titicaca basin, in both the Rio Ilave and Rio Huenque drainages, residential mobility remained high from 7000-3200 BC. Large numbers of sites are found in redundant locations on the landscape, but none show evidence of long-term residential occupations (Aldenderfer 2002; Klink 2005). A similar level of mobility is seen also in the Rio Moquegua drainage. Although these foragers did not descend into lower elevations, they did range into the margins of the puna as well as move to different residential bases in other nearby drainages (Aldenderfer 1998). More moderate levels of residential mobility are seen in the Rio Santa, where foragers practiced what Lynch (1980) has described as a form of transhumance. The highest elevations of the valley were used during the austral winter, while lower elevations were used in the summer. In contrast, the data from Pach-amachay show a remarkable pattern of sedentary occupation of the site from 8100-5900 BC (Rick 1980). Here, foragers focused their subsistence attention almost exclusively upon the hunting of vicuna, a territorial camelid that was both predictable in numbers and location. While these peoples may have made logistical forays to other sites, these were brief.
That mobile settlement patterns were maintained for much of the middle Holocene can be attributed to overall low resource densities as well as low regional-scale population densities. Even at Pachamachay, where the foragers were sedentary, there is no evidence for regional packing on the Junin puna, and indeed, the data from Telarmachay, only 35 km away, show that foragers apparently moved from the high puna to the upper reaches of the surrounding valleys on a seasonal basis (Lavallee 1987).
World History
