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Village Ecodynamics Project

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Publications

A 2,000-year reconstruction of the rain-fed maize agricultural niche in the US Southwest
Author(s): R. Kyle Bocinsky and Timothy A. Kohler
Citation: Bocinsky, R. Kyle and Kohler, Timothy A. 2014 A 2,000-year reconstruction of the rain-fed maize agricultural niche in the US Southwest. Nature Communications, 5:5618. doi: 10.1038/ncomms6618.

Humans experience, adapt to and influence climate at local scales. Paleoclimate research, however, tends to focus on continental, hemispheric or global scales, making it difficult for archaeologists and paleoecologists to study local effects. Here we introduce a method for high-frequency, local climate-field reconstruction from tree-rings. We reconstruct the rain-fed maize agricultural niche in two regions of the southwestern United States with dense populations of prehispanic farmers. Niche size and stability are highly variable within and between the regions. Prehispanic rain-fed maize farmers tended to live in agricultural refugia—areas most reliably in the niche. The timing and trajectory of the famous thirteenth century Pueblo migration can be understood in terms of relative niche size and stability. Local reconstructions like these illuminate the spectrum of strategies past humans used to adapt to climate change by recasting climate into the distributions of resources on which they depended.

[News stories were carried by several venues on this: here's one in Ukrainian: http://www.reiseklima.net/Wissen/edu/Paper-Ancient-climate-change-could-explain-historical-migration]

A Scale Model of Seven Hundred Years of Farming Settlements in Southwestern Colorado
Author(s): Timothy A. Kohler and Mark D. Varien
Citation: Kohler, Timothy A., and Mark D. Varien, 2010, A Scale Model of Seven Hundred Years of Farming Settlements in Southwestern Colorado. In Becoming Villagers: Comparing Early Village Societies, edited by Matthew S. Bandy and Jake R. Fox, pp. 37-61. University of Arizona Press, Tucson.
Empirical Bayesian Methods for Archaeological Survey Data: An Application from the Mesa Verde Region
Author(s): Ortman, Scott G., Mark D. Varien, and T. Lee Gripp
Citation: 2007 Empirical Bayesian Methods for Archaeological Survey Data: An Application from the Mesa Verde Region. American Antiquity 72:241-272.

Cultural resource databases represent the single largest compilations of archaeological site data, but these databases are seldom used in research because they were designed for management purposes, evolved from paper-based inventories, contain significant interobserver variation, and record information inconsistently. In this paper we present methods designed to alleviate these problems in an analysis of more than 3,000 ancestral Pueblo habitation sites from southwestern Colorado. Our methods draw heavily upon Bayesian statistical concepts and utilize the rich excavation records of our study area to quantify the relationship between surface evidence and excavation results using probabilities. This approach offers a number of advantages over ad hoc, judgmental approaches, and produces a more empirically justified history of ancestral Pueblo settlement in our study area. We believe methods like these have great potential for reconstructing settlement patterns from survey data.

Erratum to: Factors Controlling Pre-Columbian and Early Historic Maize Productivity in the American Southwest, Part 2: The Chaco Halo, Mesa Verde, Pajarito Plateau/Bandelier, and Zuni Archaeological Regions
Author(s): Larry V. Benson
Citation: Journal of Archaeological Method and Theory DOI 10.1007/s10816-010-9091-y
Explaining the Structure and Timing of Formation of Pueblo I Villages in the Northern U.S. Southwest
Author(s): Kohler, Timothy A., and Charles Reed
Citation: In Sustainable Lifeways: Cultural Persistence in an Ever-changing Environment, edited by Naomi F. Miller, Katherine M. Moore, and Kathleen Ryan, pp. 150-179. University of Pennsylvania, Philadelphia.

We propose that the development of leadership structures in northern Pueblo I societies can be understood as the most available solution to the assurance game (or trust dilemma) that these rapidly growing societies were faced with as they attempted to maintain traditional high levels of deer harvest in increasingly depleted landscapes. Results from agent-based models, and large faunal assemblages from the Dolores Archaeological Project, provide frameworks that underpin our assumptions and conclusions.

Factors Controlling Pre-Columbian and Early Historic Maize Productivity in the American Southwest, Part 1: The Southern Colorado Plateau and Rio Grande Regions
Author(s): Larry V. Benson
Citation: Journal of Archaeological Method and Theory DOI: 10.1007/s10816-010-9082-z

 Maize is the New World’s preeminent grain crop and it provided the economic basis for human culture in many regions within the Americas. To flourish, maize needs water, sunlight (heat), and nutrients (e.g., nitrogen). In this paper, climate and soil chemistry data are used to evaluate the potential for dryland (rain-on-field) agriculture in the semiarid southeastern Colorado Plateau and Rio Grande regions. Processes that impact maize agriculture such as nitrogen mineralization, infiltration of precipitation, bare soil evaporation, and transpiration are discussed and evaluated. Most of the study area, excepting high-elevation regions, receives sufficient solar radiation to grow maize. The salinities of subsurface soils in the central San Juan Basin are very high and their nitrogen concentrations are very low. In addition, soils of the central San Juan Basin are characterized by pH values that exceed 8.0, which limit the availability of both nitrogen and phosphorous. In general, the San Juan Basin, including Chaco Canyon, is the least promising part of the study area in terms of dryland farming. Calculations of field life, using values of organic nitrogen for the upper 50 cm of soil in the study area, indicate that most of the study area could not support a 10-bushel/acre crop of maize. The concepts, methods, and calculations used to quantify maize productivity in this study are applicable to maize cultivation in other environmental settings across the Americas.

Factors Controlling Pre-Columbian and Early Historic Maize Productivity in the American Southwest, Part 2: The Chaco Halo, Mesa Verde, Pajarito Plateau/Bandelier, and Zuni Archaeological Regions
Author(s): Larry V. Benson
Citation: Journal of Archaeological Method and Theory DOI 10.1007/s10816-010-9083-y

Chemical and nutrient analyses of 471 soil samples from 161 sites within four archaeological regions (Pajarito Plateau/Bandelier, Zuni, Mesa Verde, and the Chaco Halo) were combined with historical climate data in order to evaluate the agricultural productivity of each region. In addition, maize productivity and field-life calculations were performed using organic-nitrogen (N) values from the upper 50 cm of soil in each region and a range (1–3%/year) of N-mineralization rates. The end-member values of this range were assumed representative of dry and wet climate states. With respect to precipitation and heat, the Pajarito Plateau area has excellent agricultural potential; the agricultural potentials of the Zuni and Mesa Verde regions are good; and the agricultural potential of the Chaco Halo is poor. Calculations of N mineralization and field life indicate that Morfield Valley in Mesa Verde should be able to provide 10 bu/ac of maize for decades (without the addition of N) when organic N-mineralization rates exceed 2%. Productivity and field-life potential decrease in the following order: Zuni, Mesa Verde, Bandelier, Chaco Halo. The Chaco Halo is very unproductive; e.g., 10 bushels per acre can be achieved within the Halo only from soils having the highest organic N concentration (third quartile) and which undergo the highest rate (3%) of N mineralization.

Historical Ecology in the Mesa Verde Region: Results from the Village Ecodynamics Project
Author(s): Varien, Mark D., Scott G. Ortman, Timothy A. Kohler, Donna M. Glowacki, and C. David Johnson
Citation: 2007 Historical Ecology in the Mesa Verde Region: Results from the Village Ecodynamics Project. American Antiquity 72:273-300.

Using the occupation histories of 3,176 habitation sites, new estimates of maize-agriculture productivity, and an analysis of over 1,700 construction timbers, we examine the historical ecology of Pueblo peoples during their seven-century occupation (A.D. 600–1300) of a densely settled portion of the Mesa Verde archaeological region. We identify two cycles of population growth and decline,the earlier and smaller peaking in the late-A.D. 800s, the later and larger in the mid-A.D. 1200s. We also identify several episodes of immigration. Formation of aggregated settlements, which we term community centers, is positively correlated with increasing population and the time elapsed in each settlement cycle,and it persists during periods of regional population decline, but it does not correlate with climatic variation averaged over periods. Architectural and land-use practices depleted pinyon-juniper woodlands during the first cycle, but more stable field systems and greater recycling of construction timber resulted in more sustainable management of wood resources during the second cycle, despite much higher population densities. Our estimates for maize production are lower than previous estimates, especially for the A.D. 1200s, when population reached its peak in the study area. Even so, considerable potential agricultural production remained unused in the decades that immediately preceded the complete depopulation of our study area.

Inferring Ancestral Pueblo Social Networks from Simulation in the Central Mesa Verde
Author(s): Stefani A. Crabtree
Citation: Crabtree, Stefani A. 2015 “Inferring Ancestral Pueblo Social Networks from Simulation in the Central Mesa Verde” in special issue: The Connected Past. B. Mills and T. Brughmans (Eds.). Journal of Archaeological Method and Theory. DOI 10.1007/s10816-014-9233-8

Understanding exchange is essential for understanding past societies. The exchange of knowledge and goods undeniably influenced the development of Pueblo culture. Previous studies within southwestern archaeology have mostly focused on the exchange of material goods such as ceramics or prestige items since these items do not decay, while other day-to-day exchanges, such as the exchange of food items, are relatively undetectable in archaeology. Sahlins (1972) notes that in small-scale societies food exchange is essential for the survival of individuals in patchy landscapes. Moreover, Sahlins’s research shows that cross-culturally in small-scale societies the exchange of food is one of the fundamental structuring mechanisms for alliances. With this knowledge we may want to study the exchange of food within societies, but without being able to see the actual exchange, how can archaeologists explore the impact of food exchange given the relatively sparse archaeological record?
In this paper I use computer simulation to explore the extent to which food-sharing practices would have been instrumental for the survival of Ancestral Pueblo people across the patchy landscape of the prehispanic American Southwest and suggest that we can see direct evidence of exchange through the aggregation of households into clustered settlements. Social networks would have created stable bonds among these exchanging individuals, further helping the survival of those individuals and their progeny. Specifically, I engage Sahlins’s notion of balanced reciprocal exchange networks (BRN; when unrelated individuals rely upon reputation building to inform exchange relationships) within the experimental test-bed of the Village Ecodynamics Project’s agent-based simulation.

Long and spatially variable Neolithic Demographic Transition in the North American Southwest
Author(s): Kohler, Timothy A., and Kelsey M. Reese
Citation: Kohler, T. A. and K. M. Reese, 2014, Long and spatially variable Neolithic Demographic Transition in the North American Southwest. PNAS July 15, vol. 111, no. 28, 10103

In many places of the world, a Neolithic Demographic Transition (NDT) is visible as a several-hundred-year period of increased birth rates coupled with stable mortality rates, resulting in dramatic population growth that is eventually curtailed by increased mortality. Similar processes can be reconstructed in particular detail for the North American Southwest, revealing an anomalously
long and spatially variable NDT. Irrigation-dependent societies experienced relatively low birth rates but were quick to achieve a high degree of sociopolitical complexity, whereas societies dependent on dry or rainfed farming experienced higher birth rates but less initial sociopolitical complexity. Low birth rates after A.D. 1200 mark the beginning of the decline of the Hohokam. Overall in the Southwest, birth rates increased slowly from 1100 B.C. to A.D. 500, and remained at high levels with some fluctuation until decreasing rapidly beginning A.D. 1300. Life expectancy at 15 increased slowly from 900 B.C. to A.D. 700, and then increased rapidly for 200 y before fluctuating and then declining after A.D. 1400. Life expectancy at birth, on the other hand, generally declined from 1100 B.C. to A.D. 1100/1200, before rebounding. Farmers took two millennia (∼1100 B.C. to ∼A.D. 1000) to reach the carrying capacity of the agricultural niche in the Southwest.

Mesa Verde Migrations
Author(s): Kohler, Timothy D., Mark D. Varien, Aaron M. Wright, and Kristin A. Kuckelman
Citation: 2008 Mesa Verde Migrations. American Scientist 96:146-153.

New archaeological research and computer modeling suggest why Ancestral Puebloans deserted the northern Southwest United States.

Modeling Historical Ecology
Author(s): Johnson, C. David, Timothy A. Kohler, and Jason Cowan
Citation: 2005 Modeling Historical Ecology, Thinking about Contemporary Systems. American Anthropologist 107:96-108.
Modelling prehispanic pueblo societies in their ecosystems
Author(s): Kohler, T. A., R. K. Bocinsky, D. Cockburn, S. A. Crabtree, M. D. Varien, K. E. Kolm, S. Smith, S. G. Ortman, and Z. Kobti
Citation: Ecological Modelling, on-line corrected proofs, http://dx.doi.org/10.1016/j.ecolmodel.2012.01.002

We review a suite of agent-based models developed by the Village Ecodynamics Project (VEP) to study ecological, economic, social, and political processes among prehispanic Puebloan (“Anasazi”) populations in the Northern US Southwest in the context of a dynamic natural environment. Collectively these models shed light on processes that include the local intensification of turkey raising, the emergence of complex societies in this region, and the complete depopulation of the Northern Southwest in the thirteenth-century AD. Quantitative computational modelling contributes to the explanatory goals of a scientific archaeology and such models should eventually provide standards allowing for more rigorous comparison of distinct archaeological sequences. 

Population and Warfare: A Test of the Turchin Model in Pueblo Societies
Author(s): Kohler, Timothy A., Sarah Cole and Stanca M. Ciupe
Citation: 2009 Population and Warfare: A Test of the Turchin Model in Pueblo Societies. In Pattern and Process in Cultural Evolution, edited by S. Shennan, pp. 277-295. University of California Press, Berkeley.
Settlement Ecodynamics in the Prehispanic Central Mesa Verde Region
Author(s): Kohler, Timothy A., C. David Johnson, Mark Varien, Scott Ortman, Robert Reynolds, Ziad Kobti, Jason Cowan, Kenneth Kolm, Schaun Smith, and Lorene Yap
Citation: 2007 Settlement Ecodynamics in the Prehispanic Central Mesa Verde Region. In The Model-Based Archaeology of Socionatural Systems, edited by Timothy A. Kohler and Sander van der Leeuw, pp. 61-104. School for Advanced Research Press, Santa Fe.
Simulating Ancient Societies
Author(s): Kohler, Timothy A., George J. Gumerman, and Robert G. Reynolds
Citation: 2005 Simulating Ancient Societies. Scientific American July:76-84.
The Better Angels of Their Nature: Declining Violence Through Time among Prehispanic Farmers of the Pueblo Southwest.
Author(s): Kohler, Timothy A., Scott G. Ortman, Katie E. Grundtisch, Carly M. Fitzpatrick, and Sarah M. Cole
Citation: American Antiquity 79(3):444–464

The central Mesa Verde and the northern Rio Grande regions housed two of the densest populations of prehispanic Pueblo peoples in the North American Southwest. We plot incidence of violent trauma on human bone through time in each region. Such violence peaked in the mid-A.D. 1100s in the central Mesa Verde, and in general was higher through time there than in the northern Rio Grande region. In the central Mesa Verde, but not in the northern Rio Grande, there is a tendency for violence to be greater in periods of low potential maize production per capita and high variance in maize production, though these structural tendencies were on occasion overridden by historical factors such as the expansion and demise of the Chacoan polity and the regional depopulation. Violence generally declined through time in the northern Rio Grande until the arrival of the Spanish, even as populations increased. We propose that this decline was due to the combination of increased social span of polities, the importance of inter-Pueblo sodalities, the nature of religious practice, “gentle commerce,” and increased adherence to a set of nonviolent norms.

Las regiones de Mesa Verde central y Río Grande norte albergaron dos de las poblaciones más densas de las gentes Pueblo prehispánicas en el Suroeste Norteamericano. Registramos la incidencia de trauma producto de violencia en huesos humanos a través del tiempo en cada region. La violencia alcanzó su máximo a mediados de los 1100s A.D. en Mesa Verde central, y en general fue más alta a través del tiempo ahí que en la región de Río Grande norte. En Mesa Verde Central, pero no en Río Grande norte, hay una tendencia de incremento en la violencia en periodos de bajo potencial en la producción de maíz per capita y alta variación en la producción de maíz, aunque estas tendencias estructurales en ocasiones fueron anuladas por factores históricos como la expansión y decaimiento del gobierno de Chaco y la despoblación regional. La violencia generalmente declinó con el tiempo en Río Grande norte hasta la llegada de los españoles, incluso con el incremento de la población. Proponemos que este declive se debió a la combinación del incremento del alcance social de los gobiernos, la importancia de las sodalidades inter-Pueblo, la naturaleza de la práctica religiosa, el “comercio gentil,” y un aumento en la adhesión a un grupo de normas no violentas.

The Coevolution of Group Size and Leadership: An Agent-Based Public Goods Model for Prehispanic Pueblo Societies
Author(s): Timothy A. Kohler, Denton Cockburn, Paul L. Hooper, R. Kyle Bocinsky, Ziad Kobti
Citation: Kohler, Timothy A., Denton Cockburn, Paul L. Hooper, R. Kyle Bocinsky, Ziad Kobti 2012 The Coevolution of Group Size and Leadership: An Agent-Based Public Goods Model for Prehispanic Pueblo Societies. Advances in Complex Systems 15:xxx-xxx. DOI: 10.1142/S0219525911003256.

We present an agent-based model for voluntaristic processes allowing the emergence of leadership in small-scale societies, parameterized to apply to Pueblo societies of the northern US Southwest between AD 600 and 1300. We embed an evolutionary public-goods game in a spatial simulation of household activities in which agents, representing households, decide where to farm, hunt, and locate their residences. Leaders, through their work in monitoring group members and punishing defectors, can increase the likelihood that group members will cooperate to achieve a favorable outcome in the public-goods game. We show that under certain conditions households prefer to work in a group with a leader who receives a share of the group’s productivity, rather than to work in a group with no leader. Simulation produces outcomes that match reasonably well those known for a portion of Southwest Colorado between AD 600 and 900. We suggest that for later periods a model incorporating coercion, or inter-group competition, or both, and one in which tiered hierarchies of leadership can emerge, would increase the goodness-of-fit.

The Mesa Verde Community Center Survey - 2011 Progress Report
Author(s): Donna M. Glowacki and R. Kyle Bocinsky
Citation: Glowacki, D. and R. Bocinsky. 2011. The Mesa Verde Community Center Survey: 2011 Progress Report. Manuscript submitted to the National Science Foundation and Mesa Verde National Park, on file with Crow Canyon Archaeological Center and Washington State University in compliance with deliverable for NSF Grant DEB-0816400.

The Mesa Verde Community Center Survey (MV-CCS) is a multi-year field project that seeks to expand our understanding of the distribution and organization of large, ancestral Pueblo villages in Mesa Verde National Park (MVNP) that were occupied from AD 600-1290. The 2011 survey focused on characterizing the distribution of community centers (large, aggregated Pueblo villages) in Little Soda Canyon, and on completing documentation for those visited during the 2009 season. We delimited four community centers in the upper reaches of Soda Canyon: 1) the 34-plex excavated by Deric O’Bryan in the late 1940s; 2) the 34-plex Isolated Great Kiva; 3) Juniper Flats; and 4) Battleship Rock. Our fieldwork involved synthesizing the existing archaeological documentation done by NPS archaeologists during the Chapin V post-fire assessment to produce composite maps of these villages in order to better understand their cultural landscape. We also analyzed the pottery found on these sites to determine occupation histories of the villages (N sherds). This research is part of the National Science Foundation-funded “Village Ecodynamics Project II”, or VEP II, which is a multi-disciplinary project that seeks to understand the changing relationships between Pueblo societies and their environments.

The Mesa Verde Community Center Survey: Documenting Large Pueblo Villages in Mesa Verde National Park
Author(s): Glowacki, Donna M., with Elise Alonzi, Kyle Bocinsky, and Kelsey Reese
Citation: Glowacki, Donna M., with Elise Alonzi, Kyle Bocinsky, and Kelsey Reese, 2012, The Mesa Verde Community Center Survey: Documenting Large Pueblo Villages in Mesa Verde National Park. Ms. on File, Mesa Verde National Park and Department of Anthropology, Washington State University, Pullman.

The Mesa Verde Community Center Survey (MV-CCS) is a multi-year field project that seeks to better understand the distribution and organization of large, ancestral Pueblo villages in Mesa Verde National Park (MVNP) that were occupied from AD 600–1290. It is a component of the National Science Foundation-funded “Village Ecodynamics Project II”, or VEP II, which is a multi-disciplinary project that studies the changing relationships between Pueblo societies and their environments. We have spent three field seasons documenting community centers (2009, 2011, and 2012) and have conducted fieldwork at 13 of the largest, aggregated villages in Mesa Verde National Park. For each community center, we produced a composite map of the village that synthesizes the existing archaeological documentation done by NPS archaeologists in order to better understand their cultural landscape. We also conducted in-field pottery analysis to augment existing data and to determine occupation histories of the villages

Uniform Probability Density Analysis and Population History in the Northern Rio Grande
Author(s): Ortman, Scott G.
Citation: Ortman, Scott G., 2014, Uniform Probability Density Analysis and Population History in the Northern Rio Grande. Journal of Archaeological Method and Theory. Published on-line 28 December. DOI 10.1007/s10816-014-9227-6

One of the basic challenges facing archaeology is translating surface evidence into population estimates with sufficient chronological resolution for demographic analysis. The problem is especially acute when one is working with sites inhabited across multiple chronological periods and the production curves for pottery types are unknown. In this paper, I present a Bayesian statistical method which I call uniform probability density analysis that is tailored to this situation. This method combines uniform distributions derived from the local pottery chronology with pottery assemblage data to reconstruct the population history of individual settlements. I also illustrate applications of this method at the site and regional level using data from Cuyamungue and the surrounding Tewa Basin/VEP II New Mexico project area. The results allow one to identify a period of significant population movement corresponding to the period of Tewa ethnogenesis in the thirteenth century CE.

Entering Second Phase

The first phase of this project, VEP I, was focused on an 1800-sq-km window of the central Mesa Verde region in Colorado. We are currently working on a final report on that project, to be submitted to the University of California Press, and all of our publications through 2009 result from VEP I research.

In January 2009 we began the Village Ecodynamics Project II, which more than doubles the area under examination in southwestern Colorado and adds a comparative window in the northern Rio Grande region of New Mexico that stretches from the southern border of Bandelier National Monument north to the Chama valley. Fieldwork for this project begins in summer 2009 in Mesa Verde National Park. Some early results from this new round of research were reported at the 75th Society for American Archaeology meetings in St. Louis in 2010 and can be seen under the Presentations tab of this page.

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