Margaret C. Nelson

The cross-scale interplay between social and biophysical context and the vulnerability of irrigation-dependent societies: archaeology's long-term perspective.

What relationships can be understood between resilience and vulnerability in socialecological systems? In particular, what vulnerabilities are exacerbated or ameliorated by different sets of social practices associated with water management? These questions have been examined primarily through the study of contemporary or recent historic cases. Archaeology extends scientific observation beyond all social memory and can thus illuminate interactions occurring over centuries or millennia. We examined trade-offs of resilience and vulnerability in the changing social, technological, and environmental contexts of three long-term, pre-Hispanic sequences in the U.S. Southwest: the Mimbres area in southwestern New Mexico (AD 650–1450), the Zuni area in northern New Mexico (AD 850–1540), and the Hohokam area in central Arizona (AD 700–1450). In all three arid landscapes, people relied on agricultural systems that depended on physical and social infrastructure that diverted adequate water to agricultural soils. However, investments in infrastructure varied across the cases, as did local environmental conditions. Zuni farming employed a variety of small-scale water control strategies, including centuries of reliance on small runoff agricultural systems; Mimbres fields were primarily watered by small-scale canals feeding floodplain fields; and the Hohokam area had the largest canal system in pre-Hispanic North America. The cases also vary in their historical trajectories: at Zuni, population and resource use remained comparatively stable over centuries, extending into the historic period; in the Mimbres and Hohokam areas, there were major demographic and environmental transformations. Comparisons across these cases thus allow an understanding of factors that promote vulnerability and influence resilience in specific contexts.

Resisting Diversity: a Long-Term Archaeological Study

The value of “diversity” in social and ecological systems is frequently asserted in academic and policy literature. Diversity is thought to enhance the resilience of social-ecological systems to varied and potentially uncertain future conditions. Yet there are trade-offs; diversity in ecological and social domains has costs as well as benefits. In this paper, we examine social diversity, specifically its costs and benefits in terms of decision making in middle range or tribal societies, using archaeological evidence spanning seven centuries from four regions of the U.S. Southwest. In these nonstate societies, social diversity may detract from the capacity for collective action. We ask whether as population density increases, making collective action increasingly difficult, social diversity declines. Further, we trace the cases of low diversity and high population density across our long-temporal sequences to see how they associate with the most dramatic transformations. This latter analysis is inspired by the claim in resilience literature that reduction of diversity may contribute to reduction in resilience to varied conditions. Using archaeological data, we examine social diversity and conformity through the material culture (pottery styles) of past societies. Our research contributes to an enhanced understanding of how population density may limit social diversity and suggests the role that this association may play in some contexts of dramatic social transformation.

Archaeological and ecological perspectives on reorganization : A case study from the mimbres region of the U.S. Southwest

Collapse and abandonment dominate the popular literature on prehistoric societies, yet we know that reorganization is a more common process by which social and ecological relationships change. We explore the process of reorganization using the emerging perspective of resilience theory. Ecologists and social scientists working within a resilience perspective have argued that reorganization is an important component of long-term adaptive cycles, but it remains understudied in both social science and ecology. One of the central assumptions to emerge from the resilience perspective is that declines in the diversity of social and ecological units contribute to transformations in social and ecological systems. We evaluate this assumption using archaeological data, which offer an opportunity to investigate a time span rarely examined in studies of resilience and reorganization. We focus on the 11th to 13th century in the eastern Mimbres area of southwestern New Mexico, a period within which a substantial reorganization occurred. Much is known about the regional-scale changes that resulted in the depopulation of nearly every large village in the Mimbres region, what some have referred to as the “Mimbres collapse.” Our analyses examine both continuity and change in aspects of house- and village-level reorganization.

Understanding Abandonments in the North American Southwest

The North American Southwest is renowned for its rich archaeological record. Thousands of prehistoric houses and ceremonial centers remain partially standing or form mounds that mark prehistoric villages that were once actively occupied and remain important to the descendants. The visibility of archaeological remains has sparked interest in questions of abandonment among archaeologists and the lay public. We explore reasons for this interest, how it is manifest in archaeological research, and how perception of that research influences popular views of the past and of native people. Our focus is on explanations for the causes of site and regional abandonment as well as on explications of the processes by which abandonments occur. Essential to our perspective is the view that abandonment is a process that involves decisions to move, which may be promoted by dire circumstances, but which are most often settlement strategies. The process of moving requires economic, social, and political decisions about the places from which people move and to which they move.

Abandonment is not as it seems : An approach to the relationship between site and regional abandonment

Abandonments of residential sites by prehistoric farmers are most often explained as failures or responses to poor social or environmental conditions. These perspectives ignore the role of residential mobility among farmers as a regionally sustainable approach to land use. To understand the various reasons for abandonment of residential sites, movement patterns at both site and regional scales must be empirically linked. In this study of the eastern Mimbres area of southwestern New Mexico, we examine the relationship between site and regional occupation patterns. Rather than assume that site abandonment implies regional depopulation and that site abandonments are responses to stress or crisis, we use multiple lines of evidence to document the occupational histories of sites in an effort to evaluate whether the abandonment of villages correlates with regional abandonment. Architectural, ceramic, and chronometric data provide evidence for occupational continuity and growth of small residential sites during the twelfth century in the eastern Mimbres area in the context of the depopulation of large villages. This regional reorganization in settlement suggests a strategy for maintaining regional occupational continuity.

Climate challenges, vulnerabilities, and food security

Significance Climate-induced disasters are impacting human well-being in ever-increasing ways. Disaster research and management recognize and emphasize the need to reduce vulnerabilities, although extant policy is not in line with this realization. This paper assesses the extent to which vulnerability to food shortage, as a result of social, demographic, and resource conditions at times of climatic challenge, correlates with subsequent declines in social and food security. Extreme climate challenges are identified in the prehispanic US Southwest and historic Norse occupations of the North Atlantic Islands. Cases with such different environmental, climatic, demographic, and cultural and social traditions allow us to demonstrate a consistent relationship between vulnerability and consequent social and food security conditions, applicable in multiple contexts. This paper identifies rare climate challenges in the long-term history of seven areas, three in the subpolar North Atlantic Islands and four in the arid-to-semiarid deserts of the US Southwest. For each case, the vulnerability to food shortage before the climate challenge is quantified based on eight variables encompassing both environmental and social domains. These data are used to evaluate the relationship between the “weight” of vulnerability before a climate challenge and the nature of social change and food security following a challenge. The outcome of this work is directly applicable to debates about disaster management policy.

Grinding-tool design as conditioned by land-use pattern

The form in which archaeologists recover artifacts is the product of intentional design, use modification, and postdepositional alteration. Analysis of grinding tools, from small prehistoric sites in southwestern New Mexico, indicates the effects of intentional design and use modification on artifact form. These variables of technological behavior are considered in relation to anticipated, regular occupation of sites. Distinguishing the extent to which site visits are anticipated and regular can enhance our understanding of how places and resources were used and how land use was organized. Because grinding tools commonly remain on sites, their anticipated reuse signals anticipated reuse of the places where they occur. While characteristics of intentional design positively correlate with regularity of site occupation, the effects of use modification do not.

The Use of Chipped Lithic Material in the Contemporary Maya Highlands

Ethnoarchaeological work in the Mayan Highlands has revealed that some individuals continue to make and use chipped stone implements for the manufacture of manos and metates. As a result site formation processes, effects of resource distribution, and stone tool characteristics can still be studied. Chipped tools of industrial glass are also made and used in the area, and provide useful models for some of the prehistoric uses of flaked stone tools, as well as information relating to their storage, curation, discard, and learning contexts.

Synthesis: Vulnerability, Traps, and Transformations—Long-term Perspectives from Archaeology

In this synthesis, we hope to accomplish two things: 1) reflect on how the analysis of the new archaeological cases presented in this special feature adds to previous case studies by revisiting a set of propositions reported in a 2006 special feature, and 2) reflect on four main ideas that are more specific to the archaeological cases: i) societal choices are influenced by robustness-vulnerability trade-offs, ii) there is interplay between robustness-vulnerability trade-offs and robustness-performance trade-offs, iii) societies often get locked in to particular strategies, and iv) multiple positive feedbacks escalate the perceived cost of societal change. We then discuss whether these lock-in traps can be prevented or whether the risks associated with them can be mitigated. We conclude by highlighting how these long-term historical studies can help us to understand current society, societal practices, and the nexus between ecology and society.

Game Resources, Social Interaction, and the Ecological Footprint in Southwest New Mexico

Humans have modified their environments for millennia, but the role of these impacts on economic and social strategies among communities can be difficult to assess. This is due in part to the difficulty of quantifying impacts, which hinders our evaluations of the effects of different resource acquisition strategies and impairs attempts to understand competing demands on resources and their effects on the evolution of social relations. In this paper we employ footprint analysis, a tool used in ecology, to assess the impact of prehistoric subsistence farming communities on the environment, specifically faunal resources. We use footprint analysis to quantify the impact of various strategies of game acquisition by Classic Mimbres period (AD 1000-1130) farmers in the North American Southwest. Assessments are then employed in identifying changes in social relations among communities that may have contributed to settlement changes in the region.