ANASAZI (PRE-COLUMBIAN NATIVE-AMERICAN) MIGRATIONS DURING THE MIDDLE-12TH AND LATE-13TH CENTURIES – WERE THEY DROUGHT INDUCED (original) (raw)
Related papers
The MIDDLE-12 TH and LATE-13 TH Centuries – Were They Drought Induced ?
2007
Severe droughts in the middle-12th and late-13th centuries appear to have affected Anasazi (pre-Columbian Native American) populations. During the first drought most of the great houses in the central San Juan Basin were vacated; the second drought resulted in the abandonment of the Four Corners region. During the first drought, villages may not have been completely abandoned. The multi-year drought periods probably were characterized by reductions in both winter and summer precipitation. Maize is dependent on winter precipitation for its germination and initial growth and on summer (monsoonal) precipitation for its continued growth. Reductions in precipitation are hypothesized to have resulted in low yields of maize, the dietary staple of the Anasazi. A comparison of historic climate data and tree-ring-based reconstructions of precipitation in the Four Corners region with tree-ring-based reconstructions of the Pacific Decadal Oscillation (PDO) and the Atlantic Multidecadal Oscillat...
Quaternary Science …, 2007
One or more of three intense and persistent droughts impacted some Native American cultures in the early-11th, middle-12th and late-13th centuries, including the Anasazi, Fremont, Lovelock, and Mississippian (Cahokian) prehistorical cultures. Tree-ring-based reconstructions of precipitation and temperature indicate that warm drought periods occurred between AD 990 and 1060, AD 1135 and 1170, and AD 1276 and 1297. These droughts occurred during minima in the Pacific Decadal Oscillation and may have been associated with positive values of the Atlantic Multidecadal Oscillation. Each of the Native American cultures was supported, to a greater or lesser degree, by precipitation-dependent resources. Both the Four Corners region and Cahokia were sites of intense growth between about AD 1050 and 1130, and by AD 1150, cultures in both regions were undergoing stress. By AD 1300 the Anasazi and Fremont cultures had collapsed and their residual populations had either left their homelands or withered. In the case of Fremont populations, the AD 990-1060 drought may have had the greatest impact. This drought also may have affected the Anasazi, for it was at the end of this drought that some people from Chaco migrated to the San Juan River valley and founded the Salmon Ruin great house. Detailed data do not exist on the number of Lovelock habitation sites or populations over time; however, Lovelock populations appear to have retreated from the western Great Basin to California by AD 1300 or shortly thereafter.
Droughts, floods, and farming at Quebrada Tacahuay from late prehispanic to colonial times
We describe diachronic evidence of moisture reduction and its consequences for coastal irrigation, agriculture, and settlement at Quebrada Tacahuay, a large drainage south of the Osmore River in far southern Peru. These observations are the first for a drainage of this size and for one with occupation spanning over 12,000 years for southern eru. Following several millennia of occupation by coastal foragers, farming populations settled the lower elevations of the drainage. Our analysis indicates that agricultural production was well developed in the fourteenth century prior to a previously documented, catastrophic El Niño Southern Oscillation (ENSO) flood that took place sometime during the early-fourteenth century. Later in the fifteenth century the Inca conquest of the region and establishment of a coastal tambo and village was accompanied by agricultural expansion and the creation of new terraces. Subsequent Spanish colonization took place during the Little Ice Age and a period of increased coastal moisture. The historic and modern contraction of a large olive grove document the ongoing reduction in the coastal aquifer.
Human Vulnerability to Climatic Dry Periods in the Prehistoric U.S. Southwest
Dissertation, 2010
This study investigates the vulnerability of subsistence agriculturalists to food shortfalls associated with dry periods. I approach this effort by evaluating prominent and often implicit conceptual models of vulnerability to dry periods used by archaeologists and other scholars investigating past human adaptations in dry climates. The conceptual models I evaluate rely on an assumption of regional-scale resource marginality and emphasize the contribution of demographic conditions (settlement population levels and watershed population density) and environmental conditions (settlement proximity to perennial rivers and annual precipitation levels) to vulnerability to dry periods. I evaluate the models and the spatial scales they might apply by identifying the extent to which these conditions influenced the relationship between dry-period severity and residential abandonment in central Arizona from A.D. 1200 to 1450. I use this long-term relationship as an indicator of potential vulnerability to dry periods. I use tree-ring precipitation and streamflow reconstructions to identify dry periods. Critically examining the relationship between precipitation conditions and residential abandonment potentially sparked by the risk of food shortfalls due to demographic and environmental conditions is a necessary step toward advancing understanding of the influences of changing climate conditions on human behavior. Results of this study support conceptual models that emphasize the contribution of high watershed population density and watershed-scale population-resource imbalances to relatively high vulnerability to dry periods. Models that emphasize the contribution of: (1) settlement population levels, (2) settlement locations distant from perennial rivers, (3) settlement locations in areas of low average annual precipitation; and (4) settlement-scale population-resource imbalances to relatively high vulnerability to dry periods are, however, not supported. Results also suggest that people living in watersheds with the greatest access to and availability of water were the most vulnerable to dry periods, or at least most likely to move when confronted with dry conditions. Thus, commonly held assumptions of differences in vulnerability due to settlement population levels and inherently water poor conditions are not supported. The assumption of regional-scale resource marginality and widespread vulnerability to dry periods in this region of the U.S. Southwest is also not consistently supported throughout the study area.
Climate of the Past Discussions, 2019
This article presents the historical evidence concerning the occurrence of drought in North America from 1510-1610CE based on a comprehensive review of original written records concerning all early European expeditions into the present US and Canada. It compares this evidence from the archives of societies with maps and time series of drought generated from the tree ring-based North American Drought Atlas (NADA). This comparison demonstrates the reliability of 10 early colonial historical records as sources of evidence concerning drought, as well as the applicability of the NADA to the scale of local and regional human historical events. The comparison further verifies the occurrence and societal impacts of certain major droughts previously identified in dendroclimatological studies, but suggests that some summer hydrological deficits indicated in the tree ring record reflect a deficiency of summer rather than winter precipitation. Finally, this review of evidence from both the archives of societies and archives of nature highlights the extraordinary challenges faced by early 15 European explorers and colonists in North America due to climatic variability in an already unfamiliar and challenging environment. 1 Introduction The frequency and severity of regional droughts before the instrumental period may be reconstructed on the basis of either the archives of nature or the archives of societies. The former, which comprise natural records containing proxies for precipitation 20 or soil moisture, such as tree ring width or isotopic variations in speleothem layers, are usually employed for the more distant past and for world regions without detailed historical records. The latter, which comprise descriptions and observations of natural phenomena left by people, are usually employed for the past five to six centuries in regions with abundant personal records and official archives, such as Western Europe and China. In some cases, however, reconstructions of both types may be combined or compared in order to achieve a level of continuity, homogeneity, resolution, spatial extent and/or seasonal 25 coverage lacking in one type of archive alone, as well as to cross-check their respective results. This approach may be particularly useful where the archives of societies are plentiful enough to provide useful data but insufficient for a complete independent reconstruction of historical drought (e.g., Mendoza et al., 2006; Stahle et al., 2007). This article presents the evidence concerning the occurrence and the human impacts of droughts in North America (present US and Canada) during the first century of European exploration and colonization of the continent, 1510-1610CE, 30 based on an original comprehensive review of the primary historical sources for those expeditions. It compares this evidence from the archives of societies with drought reconstructions based on archives of nature, principally reconstructions of summer Palmer drought severity index (PDSI) from the tree ring-based North American Drought Atlas (NADA). This reconstruction and comparison serves the following four purposes: (1) to test the objectivity and reliability of these historical observations, and thus the potential for exploration and colonization records to be used in drought reconstruction; (2) to crosscheck the 35 NADA reconstructions-including those for extreme events reconstructed during the 16 th and early 17 th centuries-and the NADA's applicability to the scale of human historical events; (3) to gain further insights into the seasonality and severity of historical droughts found in each type of evidence; and (4) to better understand the human impacts of droughts during this critical and vulnerable phase of North American exploration and colonization. By 1610-with the foundation of enduring
Climate Change and Cultural Response in the Prehistoric American Southwest
KIVA, 2009
Comparison of regional tree-ring cutting-date distributions from the southern Colorado Plateau and the Rio Grande region with tree-ring-based reconstructions of the Palmer Drought Severity Index (PDSI) and with the timing of archaeological stage transitions indicates that Southwestern Native American cultures were periodically impacted by major climatic oscillations between A.D. 860 and 1600. Sitespecifi c information indicates that aggregation, abandonment, and out-migration from many archaeological regions occurred during several widespread megadroughts, including the well-documented middle-twelfth-and late-thirteenthcentury droughts. We suggest that the demographic response of southwestern Native Americans to climate variability primarily refl ects their dependence on an inordinately maize-based subsistence regimen within a region in which agriculture was highly sensitive to climate change.
The generation of paleoclimate series based on dendrochronological techniques, allows the historical analysis of climatic variability. Dendrochronology is an excellent alternative when the instrumental data bases of short extension are available, that limit to historically analyze its variability over time. The aim of this paper was to analyze the climatic variability over the past 600 years in northeastern Mexico, to determine the frequency of extreme hydroclimatic events (droughts) and their impact on society, using as proxy the growth rings of the species Pseudotsuga menziesi and Pinus cembroides. In this paper, paleoclimate series of over 400 years for the northeastern Coahuila and of 600 years for southern Nuevo León were analyzed, there were rebuilt severe droughts that had a significant impact on water availability, agricultural production, damage to livestock and therefore, a socioeconomic impact. Droughts in the northeastern region of Mexico for the period 1400-2004, have a recurrence of 50 years (p< 0.05); but more intense events were observed (p< 0.05) at intervals of 100 years; 1450, 1560, 1660, 1750-1760, 1850-1870 and 1950-1960, the latter with great social and economic impact. The reconstruction of paleoclimate series provide basic information for modeling extreme hydroclimatic events that may occur in the future under different climatic scenarios; information for substantiating technical decisions for the sustainable use of water resources in this region.
Maize and ancient Maya droughts
Scientific Reports
The ancient Maya culture of Mesoamerica shaped landscapes for centuries, in an area where maize (Zeamays) cultivation is considered a fundamental crop in the diet of present and ancient Mesoamerican cultures. Pollen records from sites with different environmental and climatic conditions of the Yucatán Peninsula (Mexico) and Peten (Guatemala) evidence a clear relationship between increased maize pollen and periods of reduced precipitation caused by El Niño Southern Oscillation (ENSO) while moist periods are characterized by low maize pollen presence. ENSO conditions were not evenly distributed across the Yucatán Peninsula, and regional droughts vary according to regional climate and geographical conditions. Our results indicate a strong relationship of increased maize and tropical forest decrease with dry periods, while the Late Preclassic Humid Period (ca. 500–200 BCE) is characterized by the absence of maize pollen. The dry Late Preclassic (300 BCE-250 CE) was a key period for incr...