The following is the established format for referencing this article:
Schoon, M., C. Fabricius, J. M. Anderies, and M. Nelson. 2011. Synthesis: vulnerability, traps, and transformations—long-term perspectives from archaeology. Ecology and Society 16(2): 24. [online] URL: http://www.ecologyandsociety.org/vol16/iss2/art24/

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

Michael Schoon ¹, Christo Fabricius ², John M. Anderies ¹ and Margaret Nelson ¹

• Abstract
• Introduction
• Testing Propositions of Management for Resilience
• Societal Choices and Robustness–Vulnerability Trade-offs
• The Influence of Robustness–Performance Trade-offs on Robustness–Vulnerability Trade-offs
• Lock-in and Persistence in the K-phase of the Adaptive Cycle
• Feedback Influencing the Perceived Cost of Change
• Can Lock-in Traps be Prevented?
• Conclusions
• Responses to this Article
• Literature Cited

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.

Key words: archaeology; robustness; trade-offs; transformation; vulnerability

1. Manage for as many potential configurations of SESs as possible. The idea of managing for multiple potential configurations is useful at the scale of a single resource system, but probably does not make sense at the scale of a society. Management, whether conscious or not, at the level of the society in the cases in this special feature relates to agricultural strategies and migration. Anderies and Hegmon (2011) show how movement between three different regions with different productivity levels can increase the resilience of a SES in the face of variability in either population changes, resource availability, or a combination of social–ecological changes. In this case, the potential configurations relate to distribution of resource abundance in three regions annually. Migration allows for populations to adjust resource-use intensity to these potential configurations. However, there are issues with how costs of migration strategies are borne depending on particular resource configurations. This emphasizes the point that increasing resilience or robustness can be costly (for some).


2. Manage at multiple scales as much as possible. The papers in the special feature provide evidence suggesting that societies, whether consciously or not, manage at multiple scales. Whereas the proposition finds support with respect to migration to and from densely populated centers and the hinterlands (Anderies and Hegmon 2011) and the distribution of resources through trade (Janssen 2011), other studies indicate the problems with failure to manage across multiple scales. Nelson et al. (2011b) identify cases where the minimization of disturbances at one scale may come at the expense of increased vulnerability to disturbances at another scale. This case illustrates real limits to the capacity to manage at multiple scales. Cross-scale institutions for trade, such as reciprocity or relation building, may build adaptive capacity through innovation and ideas from narrower or broader scales.


3. Attend to slow variables. Spielmann et al. (2011) show how people responded to the slow variable of long-term change in precipitation by gradually, that is, over centuries, shifting to permanently watered areas. This shift ultimately meant giving up a flexible strategy of frequent movement of residences and field areas that had been used for centuries to adjust to climate variability. This centuries-long solution of mobility was replaced by an adjustment to slow processes. In this case, attention to slow variables may have negative consequences by reducing the capacity of the system to adjust to fast variables. This again emphasizes the importance of trade-offs, suggesting that attending to slow variables is not sufficient. This statement might be extended to read: attend to multiple temporal scales, paying attention to trade-offs induced by various responses to particular temporal scales. Additionally, several of the papers note how social and physical infrastructure slowly build up over time in response to fast variables such as small-scale seasonal flooding in irrigation-fed agriculture and, in the process, increase vulnerability to longer term changes in slow variables, like the climatic systems (Spielmann et al. 2011, Nelson et al. 2011b). Janssen (2011) also examines the interaction of long-term population dynamics, short-term climatic variability, and the storage, sharing, and exchange of resources among spatially disparate groups. In these last examples, the cases point to a loss of resilience because of inattention or lack of understanding of the slow variables.


4. Manage for diversity. Nelson et al. (2011b) illustrate well how simplifying production for increased efficiency (Anderies et al. 2006) can contribute over the long term to dramatic transformation. The Hohokam efficient irrigation system ultimately collapsed along with social institutions, people died, and others left the region because the system became rigid and specialized on canal irrigation. The contrasting Zuni system of diverse, shifting farming locales and strategies persisted through climate changes and social changes in the region.
   
   Nelson et al. (2011b) examine why people might reduce social diversity to increase the ease of decision making in small-group settings. They show that this shift to reduced diversity in material expressions of social relations is associated with dramatic transformations in some contexts, supporting this principle but also noting some of the reasons for reductions in social diversity.


5. Accept that maintaining resilience incurs costs. Nelson et al. (2011b), in comparing the Hohokam, Mimbres, and Zuni, explore trade-offs between short-term efficiency and long-term persistence. The Hohokam system, which was heavily capitalized toward efficiency for improved productivity, collapsed most dramatically. The long-term study of this Hohokam case does show that the costs of investing in this infrastructure were, for several centuries, ameliorated through effective social networks that distributed resources widely. However, when these networks were broken, the system experienced a slow, difficult decline. The authors illustrate that the costs of any strategy are context dependent. As mentioned above, Anderies and Hegmon (2011) illustrate that maintaining resilience to climate shocks at various scales usually incurs costs for at least some groups in the system. Managing trade-offs requires attention to the specifics of each context in both short and long time frames.


6. Embrace adaptive governance. Anderies and Hegmon (2011) and Nelson et al. (2011a) examine how a flexible social system, in this case one that supports frequent movement and reorganization of people across landscapes and villages, provides the backdrop to allow solutions to difficulties. In the Mimbres case, people adjusted to population–resource challenges, climate change, and social tensions by reorganizing, rather than through short-term solutions of capitalizing their investments in land and infrastructure. The social flexibility of the system made this possible.


7. Recognize that vulnerability cannot be eliminated. Both the agent-based modeling of Janssen (2011) and the dynamic modeling of Anderies and Hegmon (2011), as well as the empirical studies presented here, strongly support the idea that robustness–vulnerability trade-offs exist and are important. In each case, societies made decisions, both implicitly and explicitly, to shift vulnerabilities temporally or spatially. In no instances were vulnerabilities wholly removed or displaced, but were shifted through societal choices.

1. Why are some societies prepared to remain in the trap of aggregation and high population density, inevitably leading to malnutrition, disease, and social conflict when they have other options? Why do others escape such traps?


2. When does the K-phase of the adaptive cycle coincide with channelization of thoughts and actions, path dependency, and lock-in that result in collapse, and what makes it possible for others to adapt before collapse and dramatic transformation?


3. How do lessons learned over the long term through archaeological research inform current trends of social–ecological systems in the K-phase, for example, increasing urbanization, continued dependence on fossil-fuel based economies, the build-up of physical and social infrastructure?

1. Rigidity and conformity in social infrastructure. Archaeological research shows that two factors were closely associated with rapid and severe transformations in these prehistoric American societies: 1) limitations in social and materials diversity, and 2) investments in infrastructure that limited options. Nelson et al.(2011a) find that, in some cases, low material diversity, such as of pottery ware, is indicative of conforming behavior preceding dramatic transformations, and postulate, along with theorists (Folke 2006), that diversity can increase resilience. Nelson et al. (2011b) show that rigidly designed, “heavy” canal systems of the Hohokam contributed to conditions that precipitated a catastrophic collapse, whereas the Zuni, who maintained a diverse suite of farming practices that were modified with changes in climate conditions, experienced a more gradual transformation. It is worth noting that the Hohokam canal system was considerably more efficient than the diversity of Zuni farming practices for boosting the productivity of arable land, but commitment to the canal system contributed to the catastrophic social and demographic collapse of the Hohokam.


2. Population size. Large populations were associated with increased settlement size (Anderies and Hegmon 2011), increased investments in infrastructure such as canals and villages (Anderies and Hegmon 2011, Nelson et al. 2011b), reduced social diversity as reflected by pottery styles (Nelson et al. 2011a), heavier reliance on agriculture because of the depletion of natural wildlife and vegetation cover (Janssen 2011, Spielmann et al. 2011), and land shortages, resulting in a perceived increase in the value of land (Nelson et al. 2011b). These factors increased the costs of resilience-enhancing strategies such as dispersal (Spielmann et al. 2011), migration (Janssen 2011), and diversification. Population could be viewed as one of the “ultimate drivers” of vulnerability (Millenium Ecosystem Assessment 2005).


3. Investment in and perceptions of physical infrastructure. In one of the prehistoric sequences examined, concentrated infrastructure in the form of large villages in the Mimbres Valley acted as attractors that drew people from other areas, leading to elevated population levels and depletion of soil and biological resources (Anderies and Hegmon). Residential infrastructure and structures for water storage and irrigation can increase water security for a given population, but the trade-off is that population often increases (Nelson et al. 2011b). This trade-off is exacerbated as people prolong their stay for cultural and aesthetic reasons, further exploiting the remaining resources (Anderies and Hegmon). Investments in infrastructure that increase attachment to place (Nelson et al. 2011b), aggregation, and densification can increase rigidity (Hegmon et al. 2008). In turn, this increase in rigidity is one of the primary factors preceding collapse through conflict, large scale emigration, and mortalities. This prolonged K-phase, as noted earlier, is associated with an increased investment of energy and time to both construct and maintain infrastructure, thereby skewing the trade-off in favor of strategies that reduce resilience. Another consequence of infrastructure investment and the associated aggregation is the neglect for other coping strategies such as migration and trade networks (Nelson et al. 2011a). This increases the perception of risk or loss associated with change, further increasing the cost of change. Societies such as the Zuni that did not invest in expensive and long-lasting infrastructure for farming, and maintained extensive social networks and distant linkages experienced less dramatic transformations than those who with greater investments in irrigation infrastructure (Nelson et al. 2011a).


4. Threat perceptions. Security, including personal safety, security of access to resources and security from disasters, is one of the core components of human well-being (Millenium Ecosystem Assessment 2005). When this is threatened, people become more inward looking and less willing to adopt resilience-enhancing strategies because of the high perceived costs. They tend to aggregate rather than disperse, opt for homogeneous rather than diverse cultural practices (Nelson et al. 2011a), and keep food and resources rather than sharing them with other groups (Spielmann et al. 2011). The challenge that emerges from the studies in this special feature is that the proximity of crises is often remote and governed by difficult to perceive, slow variables. At the same time, the speed of change to infrastructure when confronted by many of these perceived threats often requires more time and investment than is available once such threats are observed.