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Demographic Correlations of the Wari Conquest of JuninAuthor(s): David L. BrowmanSource: American Antiquity, Vol. 41, No. 4 (Oct., 1976), pp. 465-477Published by: Society for American ArchaeologyStable URL: http://www.jstor.org/stable/279012Accessed: 13/08/2010 18:59

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DEMOGRAPHIC CORRELATIONS OF THE WARI CONQUEST OF JUNIN

DAVID L. BROWMAN

The shift from llama pastoralism to potato agriculture in the Jauja-Huancayo basin of highland Peru has previously been considered a result of the Wari conquest. An alternative hypothesis, based on population pressure, is suggested here. As an adjunct to the description of population distribution, the concepts of an exploitable territory threshold model and of site catchment as a part of central place theory are explored.

MY MAJOR HYPOTHESIS is that demographic pressures contributed directly to the shift from llama pastoralism to tuber agriculture in the Jauja-Huancayo basin of the Peruvian sierra (Fig. 1) during the Early Intermediate period. I am concerned with the historical significance of this shift because it coincided with the Wari imperial expansion into the region and strongly affected the relationships between the Wari and the local population. In light of evidence derived from exploitable territory thresholds and site catchment models, I propose that the local population exceeded the carrying capacity of llama pastoralism by A.D. 400-500, resulting in a number of economic and sociopolitical shifts, and that internal rather than external factors are responsible for the shifts in economic systems.

PACI F IC

Fig. 1. Location of the Jauja-Huancayo basin.

465

AMERICAN ANTIQUITY

EARLY INTERMEDIATE PERIOD SETTLEMENTS

The archaeological evidence indicates a pattern of population increase from the first Late Pleistocene hunting groups. Until the Early Intermediate period, group fissioning was the most

probable method of alleviating population pressure, but subsequently the surrounding zones were

occupied to the extent that other alternatives had to be explored. Two major ceramic units characterize the Early Intermediate period settlements: Usupuquio

(A.D. 200-450) and Huacrapuquio (A.D. 450-600) (see Fig. 2). Survey data and test excavations

(Browman 1970, 1973) indicate the Usupuquio phases are the last in which alpaca and llama

pastoralism is the major subsistence mode. Population pressures placed a premium on more intensive land utilization techniques during the subsequent Huacrapuquio phases.

The typical wet-season Usupuquio settlement pattern is small hilltop or upper hillslope hamlets, each associated with one of the four or five valley floor centers. (The dry-season herding and

hunting encampments were mainly in the surrounding puna, outside the area of intensive survey.) The hillside hamlets ranged from 3-15 houses, yielding hamlet population estimates between 15 and 75 persons, assuming the ethnohistoric and contemporary averages of 5-6 persons per household are valid prehistorically, as indicated by the constancy in house floor areas.

Valley floor centers were utilized on a year-round basis, and show evidence of continual use over long periods. In contrast, the wet-season hillside hamlets were short-lived; some of the Usupuquio phase encampments seem to have been utilized for only one or two seasons. The population served by each of the valley floor centers is estimated to be approximately 250 persons. Thus five or six hillside hamlets are associated with each valley floor administrative and ceremonial center. The correlation of the seasonal sites with the various centers (Figs. 3 and 4) is based both on various distance measures, defined later, and on cultural remains.

Huacrapuquio phase archaeological remains suggest a cultural crisis. Population centers at the upper end of the basin are abandoned; the number of mid-basin settlements is reduced; and the heaviest population density is now at the lower end of the basin. There was increasing contact between the Jauja-Huancayo area and the Ayacucho-Huanta region following A.D. 450-500, culminating in the incorporation of the ea into the incorporation of the area into the Wari state around A.D. 600-650 (Middle Horizon epoch I B). Very specific ceramic features are shared between the contemporary Pongora or Huarpa style of Ayacucho and the Huacrapuquio style of Huancayo (MacNeish, Patterson, and Browman 1975), and Wari-derived ceramics essentially replace local wares in the subsequent Calpish phases. There is substantial evidence to suggest that the entire Wari class structure was borrowed by the Calpish peoples (Browman 1970).

While earlier settlements were seasonal, the first permanent settlements with stone architecture appear at the end of the Huacrapuquio period. Permanent year-round settlements are common by A.D. 600, with Wari-introduced towns appearing, and with structures occurring in grid patterns around rectangular courtyards and compounds. Storage buildings (colca) first appear early in the

Calpish occupation. Three important Middle Horizon temple complexes were constructed (including the famous branch oracle of Wariwilka) in areas close to the earlier Huacrapuquio centers of Orcotuna, Huacrapuquio and Sapallanga (Fig. 4).

The Huacrapuquio population shift to the south end of the valley is not wholly understood. The southern end of the basin is closest to the Wari state, and it might be argued that there were political and military reasons for the shift. However, even after extension of Wari political control far to the north, the settlements remained at the south end of the valley. Local rain shadow effects

appear to be a more important consideration. The southern end of the valley receives 100 mm more rain than the northern (740 mm versus 635 mm, Browman 1970); and today year-round gardening is practiced at the southern end while only seasonal agriculture is possible at the northern end. Thus agriculture seems to be a strong factor in the population shift in the

Huacrapuquio and Calpish phases. Striking changes are evidenced in the lithic assemblages as well. From the earliest evidence

through the Usupuquio phases, lithic assemblages are dominated by hunting implements and tools associated with carcass processing, with a slight shift in tool inventories noted about the fourth millennium B.C. associated with the shift from hunting to pastoralism. This lithic assemblage undergoes a dramatic change in the Huacrapuquio phases, and by the Middle Horizon hunting and

[Vol. 41, No. 4, 1976 466

WARI CONQUEST OF JUNIN

Jauja-Huancayo

Terminal Preceramic

2000 B.C. Tinyari

Southern Sierra

Cachi

Northern Sierra Coastal Peru

Lauricocha III Gaviota

1800 B.C.

1600 B.C.

1400 B.C.

1200 B.C.

Early Horizon

1000 B.C.

800 B.C.

600 B.C.

400 B.C.

200 B.C.

Early Intermediate Period

0 A.D./B.C.

A.D. 200

Pirwapuquio Marcavalle Kotosh- levels DEF/4

Wichqana

Atalla Chanapata

Cochachongos

Rancha

Chupas

Uchupas

Usupuquio

Kotosh- levels BC/23

Chavin-Mosna and San Bias

San Bias

Huaylas

Wimpilley

Curayacu CD

Los Patos

Ocucaje 8-10

Topara (Chongos)

Miramar

Caja

Middle Horizon

Late Intermediate Period

Late Horizon

Colonial

Republican

A.D. 400 Huacrapuquio Huarpa

Chakipampa A.D. 600 Calpish Ocros

Vifiaque

A.D. 800 Quinsahuanca (Huarpa 11) Coras Pillpintuyoq

A.D. 1000

A.D. 1200

Matapuquio

Arhuaturo

A.D. 1400 Arhuaturo-lnca Viques Llaqsa

A.D. 1600 Ocopa

Retama

A.D. 1800

A.D. 2000

Arjalla Patarjay

Inca (Angara)

Huamachuco Cajamarca III

(Chimu?)

Nieveria

Pachacamac AB (Atarco)

Pachacamac-I nca

Modern

Fig. 2. Jauja-Huancayo phases compared with other Peruvian sequences.

carcass processing implements have completely disappeared, and are replaced by agricultural tools. This crucial epoch, perhaps no more than a century in duration, marks the shift from primary

llama and alpaca pastoralism, with secondary hunting and horticulture, to a new economic base of primary agriculture with secondary herding.

Initial Period

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WARI CONQUEST OF JUNIN

LLAMA PASTORALISM AS AN ADAPTIVE STRATEGY

Llama pastoralism is an efficient adaptive stategy under certain population conditions. The earliest domestic camelids or ilamoids are found at Pachamachay rockshelter near Lake Junin around 5000 B.C. and at Pikimachay cave in Ayacucho around 4500-4000 B.C. The period from 4000-1000 B.C. marks an epoch of manipulation of phenotypic characteristics of the llamoids and an epoch of consolidation and integration of the pastoral regime.

In investigating the pressures causing a shift from a pastoral exploitative strategy to an

agricultural one, it is useful to outline the selective forces favoring pastoralism. I have dealt with this question elsewhere (Browman 1973, 1974) and here only outline a few points.

(1) The extremely variable meteorological conditions in the high Andes place a premium on mobility, favoring pastoralism as a subsistence mode, and upon a diversity of resources, favoring the development of secondary subsistence modes such as horticulture and trade networks, and technological specialization such as mining and pottery manufacture.

(2) Pastoralism is integrated into and maintains the structure of the previous hunting ecosystem. It is a conservative innovation that preserves the former nomadic hunting lifeways to a greater extent than other alternatives.

(3) Pastoralism is a response to population pressure. It permits more efficient exploitation and

predators, may crop approximately ten percent of the available biomass (Schaller 1972; Pimentel and Soans 1971; Martin 1973). The shift to pastoralism eliminates the competition of other predators, reduces social intolerance and its genetic limitation on host species reproduction, reduces effects of weather and vagaries in food supply, and thus permits human groups to crop a much greater percentage, in some cases as much as 20-30% of the herbivore biomass.

(4) The Andean puna and altiplano are areas of high forage productivity for herd animals, but are in general poorly suited for cultivated crops. In such an environment, llama pastoralism allows cultural expansion by enlarging the resource fields to sources previously not exploitable.

(5) There are pressures from surrounding agricultural groups upon the pastoralists that act as positive feedback, reinforcing pastoralism. Trade with nomadic pastoralists is one way that settled agriculturalists may continue to utilize resources that they formerly exploited, but which their sedentary lifestyle has removed from their local resource field.

EXPLOITABLE TERRITORY THRESHOLD MODEL

A human population finds it profitable to directly exploit resources in the vicinity of their occupation site. The cost curve rises geometrically as distance increases from the occupation site (Fig. 5). Distance and its associated costs may be conceptualized as having four major components: (1) geodesic distance, the straight line distance between two points; (2) pheric distance, the time needed to cover topographic space, such as hills versus plains; (3) transport costs, such as the energy costs for the hunter to bring game back to camp, the agriculturalist to bring field produce back to the settlement, as well as the more traditional sense of transporting goods to market centers; and (4) social and psychological costs, such as incurred when the hunter's game or the farmer's field are far enough away to require temporary separation from the social community. There will be one range where returns increase more rapidly than costs, the preferred territory of exploitation (up to Threshold A); a second range where costs rise sharply toward a limit of what is considered a maximum range of economic exploitation (Threshold B); and a marginal range where exploitation is considered uneconomic, and which is generally not exploited without modification of the system of exploitation, establishment of new settlements, or in periods of economic crisis (between Thresholds B and C).

Sedentary populations, such as agriculturalists, have distance costs that are different from mobile economies, such as herders and hunters. A major constraint upon the territory that can be effectively exploited, in both cases, is that it lies within a day's round trip from the occupation site. The form of the curve in Fig. 5 will be the same for both, but the numerical values of the thresholds will be different.

Browman] 469

AMERICAN ANTIQUITY

EXPLOITABLE TERRITORY

THRESHOLDS

A B /

/

n Z z/ economic and 0 iI

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0\

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_ - g rgross /

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DISTANCE

Fig. 5. Exploitable territory thresholds model.

Estimation of numerical values for mobile economies is difficult, for although there are substantial data on hunting and politically defined territories, there is little information on the territory exploited from a single encampment. African and Australian data indicate that in areas of high vegetative food yields, limits on collecting are more important than those on hunting, while evidence from northern Canada suggests the reverse is true where meat sources are the more important energy sources. The Pitjandjara of the western Australian desert (Tindale 1972) select campsites on the basis of game within easy walking distance for the men, and plants, grubs, and small animals within easy collecting distance for the women. The women prefer these sources within 2-3 km; begin complaining when they must go 4-5 km; and begin to rebel when they must go more than 5-6 km. Among the Hadza of eastern Africa (Woodburn 1968, 1972), the women collect within a radius of 4-5 km or a one hour's distance; the men may go further to hunt, but generally abandon a wounded animal if it is not caught within a day's journey from camp. Hunting in other geographic areas is comparable: Great Basin Shoshone hunt within a radius of one day's journey, a maximum radius of 35 km (Steward 1938; Thomas 1972), and Bolivian Siriono initiate a hunt only if the spoor is within a half-day's walk of camp (Holmberg 1969).

The best data come from the Bushmen of southern Africa. Threshold A is about a two-hour hike (7-10 km) for both the G/wi Bushmen of the Kalihari desert (Silberbauer 1972) and the !Kung Bushmen of the Dobe (Lee 1968, 1969, 1972). For the !Kung Bushmen, Threshold B is reached between 16 and 22 km and Threshold C is reached at approximately 30-35 km.

Data for threshold estimations for agricultural settlements are more abundant. In the most encompassing survey, Chisholm (1968) noted that at one km, the decline in net return was significant as a factor adversely affecting the prosperity of the subsistence agriculturalist; at 3-4 km, the costs rise sufficiently to be oppressive; and beyond 3-4 km the costs of cultivation become prohibitive without modification of the system of cultivation or settlement.

470 [Vol. 41, No. 4, 1976

WARI CONQUEST OF JUNIN

The same regularities have been observed in studies of central place theory. In the United States and England (Loesch 1954; Brush and Bracey 1955), Germany (Christaller 1966), Rhodesia (Roder 1969), and China (Skinner 1964), the lowest level agricultural central places are spaced with maximum exploitative areas of 4-6 km radius, or one hour's walking distance. Morrill (1970) estimates that with modern transportation this radius is closer to a half-hour maximum.

Archaeological studies allow us to extend this threshold backward in time. Hodder (1972) found the preferred distance in Roman Britain was a radius of 3-6 km; Hammond (1972, 1974) and Bullard (1960) noted a radius of 3-6 km among the lowland Maya; and Adams (1972) has indicated a radius of perhaps 3-8 km in Mesopotamia.

Most agricultural studies have been of permanent rather than shifting cultivation. However, studies of the Maya as well as those in Amazonia (Carneiro 1956; Butt 1970) and New Guinea (Clarke 1971) indicate that for shifting cultivation, farming is impracticable much beyond 5 km, with a maximum radius of 7-8 km. Thus the one hour radius limit appears to hold for subsistence agriculture, whether based upon permanent irrigation or on any of a variety of fallowing systems.

SITE CATCHMENT MODEL IN PERU

Using data similar to the above, Higgs, Jarman, and Vita-Finzi (Jarman 1972; Higgs and Vita-Finzi 1972; Jarman, Vita-Finzi and Higgs 1972) developed a model termed "site catchment." Under their model, the critical threshold (Threshold A in Fig. 5) for hunting and gathering

walking distance: thresholds which would permit an effective working day after discounting travelling time. These limits appear to be the same as those postulated for classical central place theory. In one formulation of that theory, Christaller (1966:159-60) regarded one hour's distance as the basic measure for the establishment of the size of the lowest ranked region, and suggested the time-measure had an important geographical effect in determining the number and distribution of central places. Investigation of site catchment therefore can provide results that will partially explain the economic and social costs which determine the location of settlements.

In applying the site catchment model to the Peruvian llama pastoralists, I have hypothesized that the intermittently occupied, wet-season sites and their distances from the recurrently utilized valley floor administrative centers should be described by one of the two limits developed: either the one hour walking distance limit (34 km in the basin) or in the two hour walking distance limit (6-8 km). Because the constraints placed on herding are more similar to those of hunting than to those of farming, I expected to find the distance to be the two hour limit, 6-8 km.

The Early Intermediate period data (Figs. 3, 4, 6) appear to support this prediction. In Fig. 6, there are two modes of clustering in the sample of 90 sites (55 Uspuquio and 35 Huacrapuquio): one mode about 3 km from the centers, and a second mode about 6-7 km from the centers. The major mode of 6-7 km is just that hypothesized, the two-hour limit; the apparent mode at 3 km needs further examination. Of the 90 sites, only three lie at significantly greater distances than 11 km. Two of these were guard or lookout sites and should not be expected to conform to the same restrictions regarding effective distance from centers. The third may belong to a center outside my survey area.

The administrative centers also appear to conform to the distance patterns as predicted by our two models. The sample is too small to be statistically significant, but the centers appear to be located more than an effective day's round trip apart. The median distance separating administrative centers is 21 km; this is about twice the observed distance of 11 km that appears to be the maximum effective exploitative distance from each respective center. With reference to the exploitable thresholds model (Fig. 5), the value of Threshold A is 6-7 km, and the value of Threshold B is about 11 km.

POPULATION GROWTH AND DEMOGRAPHIC CRISIS

A basic assumption here is that with the exception of a few marginal groups, human populations do not reach homeostasis, but operate as systems of inherent growth, a concept

Browman] 471

AMERICAN ANTIQUITY

Distance Of Seasonal Occupation Sites From Valley Floor Centers

Early Intermediote Period, Jauja-Huancayo

20-

18-

16-

14-

E

...

..............'.'

6 - ..: .. .3 ..4 - - 7.......... 8 9 1 113 1 1517 ............ ........

:: .......':::::: ... . ...........

0 1-2 3 4 5 6 7 8 9 I0 II 12 13 14 15 16 17 18

Number Of Kilometers From Ceremonial And Administrative Sites

Fig. 6. Site catchment distances for the Usupuquio and Huacrapuquio phases.

(1972), and Cohen (n.d.). Several factors may reduce the llama and alpaca herds below the level adequate for the

minimum, household-maintaining herds; the factor I am isolating is human population growth. For human populations to continue to grow in a pastoral regime, there must be continually increasing herd sizes. At some point, the carrying capacity of the land with respect to grazing is reached, inhibiting further growth in herd size, and the human population, still growing, reaches what might be termed a demographic crisis.

Continued growth of the human population will result in herd sizes below the socially and economically viable minimum. The pastoral group may choose to attempt to reach a steady state through birth control, infanticide, warfare, and other population reducing mechanisms. A second choice is to increase the efficiency of resource utilization. The shift from guanaco hunting to llama herding was one step toward more efficient use of the animal biomass. The shift to plant energy sources is another step. Plant exploiters utilize a primary level of trophic energy whereas herders exploit a second, less efficient level, in which the herd animals serve as intermediaries between

plants and man. Therefore agriculture permits intensification of available energy through application of new techniques, and higher population densities may be maintained.

In the case of the Jauja-Huancayo basin, I propose that the human population had grown so large by the end of the Early Intermediate period that the pasture within reasonable access was insufficient to support continually greater herd numbers, thus making it impossible to maintain a lifestyle predicated primarily upon llama and alpaca pastoralism. Population densities of surrounding zones were large enough that it was no longer possible to reduce local densities by fissioning and emigration. This population expansion and new agricultural emphasis is also noted

472 [Vol. 4'1, No. 4, 1976

WARI CONQUEST OF JUNIN

north of our study area in the puna around Lake Junin and Lake Lauricocha (Cardich 1974), where hunting and pastoralism were dominant previously.

To demonstrate a demographic crisis, it is necessary to determine the minimum herd size under primary pastoralism, the upper limits on the number of animals which could be herded without degradation in the basin, and to then show that the human population was greater than could have been supported under primary pastoralism.

If a major portion of nutrition is to be derived from pastoralism, then the average size of the lama and alpaca herds must be significantly larger than the size of contemporary llama herds, maintained primarily for wool and pack animals. The average size of contemporary herds is 70 animals per household (Browman 1974); herd composition and fertility are such that the annual increase to meet social and economic obligations is only 6-8. If the same low fertility and high mortality were also the case for earlier herds, and if the earlier herd composition was more similar to that of other ethnographically-known primary pastoralists, then I have estimated (Browman 1973) a herd size for primary llama and alpaca pastoralism to be 150-200 animals per household. Thus herd sizes per household pre-A.D. 500 must be two to three times larger than the post-A.D. 500 economic reorientation.

Estimates of the maximum number of llama and alpaca which could have been herded within reasonable access without environmental degradation are more difficult. Quantitative data are practically non-existent, so I have used two different models to arrive at estimates. Both estimates are based on a guess that the Early Intermediate period population probably exploited land no morer than three days'journey from the valley. The problem of overlap of the exploitation areas of different ethnic groups was ruled out to simplify the estimating procedures, but as population densities increase, such overlap becomes a significant factor contributing to the demographic pressre on the resource base. Based on the estimates obtained from the ththrhold and catchment models, this three days' radius is equivalent to about 30 km, corresponding to an area of exploitation for the basin of 8,400 km2 or 840,000 ha.

The Biomass Estimate. The first estimation of the maximum number of llamas and alpacas on this 840,000 ha is based on biomass estimates worked out in Africa, Asia, and North America for the maximum animal units per section that various biotopes can support. Grasslands such as the Andean punas theoretically should be capable of carrying ten animal units per section (Martin 1973). Converting English to metric units, the equivalent is 1.75 kg/ha, or in terms of current weight distribution statistics, the amount of land required to support one alpaca or llama will vary between 3 and 5 ha. Thus 168,000-280,000 animals could be supported on the 840,000 ha. Conversion factors are based partly on the carrying capacity with reference to European domesticates, but the llamas and alpacas are between 10 and 50% more efficient than cattle and sheep. in metabolizing the high cellulose grasses, depending on the forage species (Fernandez Baca 1971). This increase in metabolizing efficiency will increase the carrying capacity in terms of animal numbers, but it is not directly calculable. It does indicate, however, that the number of animals under this estimate is low.

The Ethnographic Estimate. My second estimate is based on recent figures on land needed by different age and sex sets of camelids (Maccagno 1932; Flores Ochoa 1968). These figures indicate that each animal requires 1.5-3.5 ha, or that the sample area could support 240,000-560,000 animals.

These two estimates of carrying capacity are roughly within the same range: the biomass estimate 168,000-280,000 camelids, and the ethnographic estimate 240,000-560,000 camelids. In terms of our problem, we need to know how many people could be supported under primary pastoralism for these estimates. If an average of 200 animals per household is used (Browman 1973), then the biomass estimate suggests a maximum of 840-1,400 households and the ethnographic estimate 1,200-2,800 households.

To indicate demographic pressure, the number of households during the Early Intermediate period should be greater than the maximum number of households estimated possible above. To obtain estimates of household numbers in the basin, I used two separate procedures.

The Survey Estimate. The first estimate is based on my survey data on 305 sites in the basin

Browman] 473

AMERICAN ANTIQUITY

(Browman 1970 and unpublished field notes). To simplify computation, I assumed that I had located 100 percent of the occupation sites, that I had made accurate site measurements, and that the estimates of population ranges were approximately correct. These assumptions may short-change the data and will yield low estimates, but they have allowed numerical approxima- tion. This estimating procedure yielded the following household counts (variation due to survey data):

A.D. 250 Usupuquio phase 300-450 households A.D. 500 Huacrapuquio phase 900 households A.D. 750 Calpish phase 1,600-3,200 households

The Population Increase Estimate. My second estimate is based on an assumption of a constant population increase rate. Patterson (1971) argued that an annual increase of 0.20-0.25% will generate the observed population densities on the central coast of Peru. The second estimating procedure assumes that this rate of increase can usefully be extended to the central highland Jauja-Huancayo region. Ethnohistoric census data (Browman 1970; Vega 1965) indicate 30,000 households in the Jauja-Huancayo basin at the Spanish conquest in A.D. 1532. Using these figures, the following household counts may be computed:

A.D. 250 Usupuquio phase 900 households A.D. 500 Huacrapuquio phase 1,800 households A.D. 750 Calpish phase 3,600 households

From carrying capacity computations, the maximum number of households possible for a primarily pastoral subsistence mode was 800-1,400 households using the biomass estimate, and 1,200-2,800 households using the ethnographic model estimate. But household estimates computed by the survey data and population increase estimating procedures indicate actual household counts as large as 3,200-3,600 households during the early Middle Horizon Calpish phases. The fact that the number of households during the Calpish phases is substantially greater than predicted on the basis of carrying capacity estimates under a primarily pastoral subsistence mode strongly suggests that llama pastoralism was no longer the major subsistence base. One may infer from the known data and the above discussion that a demographic crisis occurred during the late Early Intermediate period when the carrying capacity of the region with respect to llama pastoralism was surpassed.

Other modes of subsistence (agriculture) were then required to support the growing human population. Because other highland communities were wholly agricultural for at least 3,000 years before the Jauja-Huancayo area abandoned its pastoral mode, acquisition of knowledge of agricultural techniques is not an explanation. The population in the Jauja-Huancayo area was clearly aware of agricultural technology, but preferentially chose to maintain a pastoral lifestyle until the Middle Horizon. Another explanation must be offered for the subsequent change in economic orientation: this analysis suggests that it was population pressure.

CONCLUSION

There was a shift from primary pastoralism to primary agriculture in the Jauja-Huancayo basin approximately A.D. 500. The Jauja-Huancayo basin was incorporated into the Wari empire approximately A.D. 500. One possible explanation for the co-occurrence of these two events is that the Wari people, through military conquest, forced the change in subsistence mode from herding to farming.

Demographic and carrying capacity data summarized in this paper, however, imply that even if there had been no Wari conquest, the valley would still have shifted from pastoralism to agriculture at the same time. Population control was not effective in maintaining a zero population growth. Group fissioning, as an alternative to alleviate population pressure, functions only as long

474 [Vol. 41, No. 4, 1976

WARI CONQUEST OF JUNIN

as there are underutilized areas for the new groups to exploit. By the Early Intermediate period, fissioning was no longer a viable alternative as the empty space no longer existed, and other alternatives for maintaining a larger population, such as increasing the economic base by shifting to agriculture, were explored.

The demographic crisis experienced at this time made the people receptive to the advances being made by the forming state in the Ayacucho area. The Huacrapuquio polity in Huancayo extensively borrowed cultural traits from the Pongora-Huarpa polity in Ayacucho. I suggest the reason the Jauja-Huancayo area was so completely dominated by Wari concepts was that the basin was experiencing social disorganization due to the collapse of its pastoral mode just at the time of the Wari expansion. Therefore the inhabitants of the Jauja-Huancayo area were extremely receptive to the new modes of organization represented by the Wari expansion, and accepted them in a wholesale fashion that is otherwise very difficult to explain. If the Wari capital was over-extended in its local valley as Isbell (1973) has suggested, then there was additional reason for them to aid in the rapid conversion of the Jauja-Huancayo lands to their full agricultural potential. Thus the Jauja-Huancayo area may have been an important logistical support area for the Wari just

Acknowledgments. Fieldwork was partly supported by a NSF grant. An earlier version of this paper was presented at the 39th Annual Meeting of the Society for American Archaeology in Washington, D.C. I am indebted to Robert Canfield, William Isbell, Jonathan Kent, Edward Robbins, Robert Sussman, and Patty Jo Watson for valuable comments on later drafts.

Adams, R. McC. 1972 Patterns of urbanization in early southern Mesopotamia. In Man, settlement and urbanism, edited by

P. J. Ucko, R. Tringham, and G. W. Dimbleby, pp. 73549. Schenkman, Boston. Boserup, E.

1965 The conditions of agricultural growth: the economics of agrarian change under population pressure. Aldine, Chicago.

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