Drivers of global variation in land ownership

Land ownership shapes natural resource management and social–ecological resilience, but the factors determining ownership norms in human societies remain unclear. Here we conduct a global empirical test of long‐standing theories from ecology, economics and anthropology regarding potential drivers of land ownership and territoriality. Prior theory suggests that resource defensibility, subsistence strategies, population pressure, political complexity and cultural transmission mechanisms may all influence land ownership. We applied multi‐model inference procedures based on logistic regression to cultural and environmental data from 102 societies, 71 with some form of land ownership and 31 with no land ownership. We found an increased probability of land ownership in mountainous environments, where patchy resources may be more cost effective to defend via ownership. We also uncovered support for the role of population pressure, with a greater probability of land ownership in societies living at higher population densities. Our results also show more land ownership when neighboring societies also practiced ownership. We found less support for variables associated with subsistence strategies and political complexity.     

The resilience of social norms of cooperation under resource scarcity and inequality — An agent-based model on sharing water over two harvesting seasons

Water governance remains a challenge for human societies, especially when the variation in resource inflow is large and the resource users are heterogeneous. We analyze with a coupled social-ecological systems (SES) model how socioeconomic and environmental changes affect the resilience of social norms governing resource use. In our model, agents have access to water as a common-pool resource and allocate it between rainy and dry seasons. While it is socially optimal to save water for the dry season, it is individually optimal to take water immediately. In our model, punishment of norm violators is the mechanism that may sustain cooperation. We show that the resilience of social norms could be affected by changes in socioeconomic and environmental conditions. Particularly, we find that social norms may collapse in times of resource scarcity and variability, especially if several drivers act in concert. Finally, we find that user heterogeneity in the form of different skills and inequality in land endowments may undermine cooperation. This implies that climatic changes and increased inequality – both potential drivers in the field – may affect community resilience and may lead to an erosion of social norms.     

Social consequences of rapid environmental change

While direct influences of the environment on population growth and resilience are well studied, indirect routes linking environmental changes to population consequences are less explored. We suggest that social behavior is key for understanding how anthropogenic environmental changes affect the resilience of animal populations. Social structures of animal groups are evolved and emergent phenotypes that often have demographic consequences for group members. Importantly, environmental drivers may directly influence the consequences of social structure or indirectly influence them through modifications to social interactions, group composition, or group size. We have developed a framework to study these demographic consequences. Estimating the strength of direct and indirect pathways will give us tools to understand, and potentially manage, the effect of human-induced rapid environmental changes.     

A comprehensive resilience assessment of Mexican tree species and their relationship with drought events over the last century

The resilience of forests to drought events has become a major natural resource sustainability concern, especially in response to climate change. Yet, little is known about the legacy effects of repeated droughts, and tree species ability to respond across environmental gradients. In this study, we used a tree-ring database (121 sites) to evaluate the overall resilience of tree species to drought events in the last century. We investigated how climate and geography affected the response at the species level. We evaluated temporal trends of resilience using a predictive mixed linear modeling approach. We found that pointer years (e.g., tree growth reduction) occurred during 11.3% of the 20th century, with an average decrease in tree growth of 66% compared to the previous period. The occurrence of pointer years was associated with negative values of the Standardized Precipitation Index (SPI, 81.6%) and Palmer Drought Severity Index (PDSI, 77.3%). Tree species differed in their resilience capacity, however, species inhabiting xeric conditions were less resistant but with higher recovery rates (e.g., Abies concolor, Pinus lambertiana, and Pinus jeffreyi). On average, tree species needed 2.7 years to recover from drought events, with extreme cases requiring more than a decade to reach pre-drought tree growth rates. The main abiotic factor related to resilience was precipitation, confirming that some tree species are better adapted to resist the effects of droughts. We found a temporal variation for all tree resilience indices (scaled to 100), with a decreasing resistance (−0.56 by decade) and resilience (−0.22 by decade), but with a higher recovery (+1.72 by decade) and relative resilience rate (+0.33 by decade). Our results emphasize the importance of time series of forest resilience, particularly by distinguishing the species-level response in the context of legacy of droughts, which are likely to become more frequent and intense under a changing climate.     

Stability and resilience in East African Pastoralism: The Rendille and the Ariaal of northern Kenya

The social organizations of two closely related nomadic pastoral societies of northern Kenya, the Rendille and Ariaal, are compared in the context of the relative constancy and variability of their herding environments. It is concluded that the application of Brooks and Yellen's model of stability and resilience in human populations is of value in understanding the impact of environmental constraints on social organization, but it is argued that other social features including the organization of labor and ownership of different livestock types directly bear on the differences between the Rendille and Ariaal.     

Pre-Hispanic Beer in Coastal Peru: Technology and Social Context of Prehistoric Production

The native Andean beer , chicha, played a variety of roles in pre-Hispanic Peruvian societies. Commonly made from maize , chicha was both the everyday beverage and an essential element in ritual and social interactions. Most important, political leaders had to reward corvée labor groups with chicha and food as part of the "hospitable repayment" lords were obligated to provide their subjects. The article describes an archeological investigation of chicha production in a non-elite residential sector at Manchan, the Chimu Empire's (A.D. 900–1470) regional center in the Casma Valley of the Peruvian North Coast. Two issues are considered: the technical process and the social context of chicha- making. In both cases, ethnohistoric and ethnographic data are used to develop archeological correlates for different aspects of the technology and social context of chicha- making. The archeological data indicate that (1) the equipment for chicha- making was generally available, (2) different households episodically produced large quantities of chicha, and (3) this production took place within a self-sufficient household and without extensive state involvement by the Chimu Empire.     

Community Resilience in Southern Appalachia: A Theoretical Framework and Three Case Studies

A fundamental assumption in nearly all research on social adaptation to environmental change is that there is a concomitant and inverse relationship between human communities’ dependence upon particular natural resources affected by environmental change and those communities or societies’ resilience to disturbances. However, recent theoretical and empirical developments suggest resilience is a dynamic social process determined, in part, by the ability of communities to act collectively and solve common problems. The interactional approach to community is utilized to develop a framework whereby various patterns of social interaction define the process of social resilience. Data come from multiple mixed methods case studies of forest dependent communities within Southern Appalachia. The findings reveal varied processes of social resilience can occur in communities with similar levels of resource dependence; a community’s composition of internal social ties and their cross-scale linkages to external agencies and organizations define these processes.     

The relationship between altitude and group size in mountain baboons (Papio cynocephalus ursinus)

Twenty-seven troops were counted during a 1989 census of the mountain baboon population at Giants Castle Game Reserve. In contrast to earlier findings, and despite a similar population structure, we found no relationship between group size and altitude. We argue that this is a consequence of long-term population processes whereby groups split as they grow larger and, in some cases, as their home ranges expand upward. At these high altitudes, smaller groups are eventually subjected to environmental conditions that destroy them. We propose that the high-altitude slopes act as a demographic sink.     

Earthquakes as the Quintessential SCE: Methodology and Societal Resilience

This paper focuses on earthquakes as the most frequent type of SCE (short-term cataclysmic event) with signatures in the three main sources used to reconstruct the premodern environment, namely historical records, archaeological findings, and paleoclimate proxies. We examine methodological issues in archaeoseismology (including earthquake catalogs, statistics, and the measurement of societal resilience to earthquakes in premodern societies in the eastern Mediterranean), before investigating societal earthquake response in the region. The behavior of different groups within these societies, such as the central government or local elites, is assessed in this context. The regenerative or adaptive aspects of seismic events are demonstrated with consideration of their archaeological footprints. This paper concludes that complex societies in the Eastern Mediterranean during the past two millennia were largely resilient to earthquakes at the state-level, though local effects on the aspect and character of urban settlement could be more pronounced.     

Self-assembly,self-organization and division of labour

The prospect of generic principles of biological organization being uncovered through the increasingly broad use of the concepts of ''self-assembly'' and ''self-organization'' in biology will only be fulfilled if students of different levels of biological organization use the same terms with the same meanings. We consider the different ways the terms ''self-assembly'' and ''self-organization'' have been used, from studies of molecules to studies of animal societies. By linking ''self-assembly'' and ''self-organization'' with division of labour, we not only put forward a distinction between the underlying concepts but we are also able to relate them to the question: Why has a certain structure been favoured by natural selection? Using the particularly instructive case of social resilience in ant colonies, we demonstrate that the principle of self-organizing self-assembly may apply to higher levels of biological organization than previously considered. We predict that at the level of interactions among organisms within the most advanced animal societies, specialization through learning has a crucial role to play in re-assembly processes. This review may also help important commonalities and differences to be recognized between ordering mechanisms up to the social level and those further up the biological hierarchy, at the level of ecological communities.     

Life history and development--a framework for understanding developmental plasticity in lower termites

Termites (Isoptera) are the phylogenetically oldest social insects, but in scientific research they have always stood in the shadow of the social Hymenoptera. Both groups of social insects evolved complex societies independently and hence, their different ancestry provided them with different life-history preadaptations for social evolution. Termites, the 'social cockroaches', have a hemimetabolous mode of development and both sexes are diploid, while the social Hymenoptera belong to the holometabolous insects and have a haplodiploid mode of sex determination. Despite this apparent disparity it is interesting to ask whether termites and social Hymenoptera share common principles in their individual and social ontogenies and how these are related to the evolution of their respective social life histories. Such a comparison has, however, been much hampered by the developmental complexity of the termite caste system, as well as by an idiosyncratic terminology, which makes it difficult for non-termitologists to access the literature.
Here, we provide a conceptual guide to termite terminology based on the highly flexible caste system of the "lower termites". We summarise what is known about ultimate causes and underlying proximate mechanisms in the evolution and maintenance of termite sociality, and we try to embed the results and their discussion into general evolutionary theory and developmental biology. Finally, we speculate about fundamental factors that might have facilitated the unique evolution of complex societies in a diploid hemimetabolous insect taxon. This review also aims at a better integration of termites into general discussions on evolutionary and developmental biology, and it shows that the ecology of termites and their astounding phenotypic plasticity have a large yet still little explored potential to provide insights into elementary evo-devo questions.     

End‐of‐life product management as a resilience driver for developing countries: A policy experiment for used tires in Ecuador

Over the last decades, a number of new environmental policies have been designed to improve waste management. Among them, extended producer responsibility (EPR) has introduced a mechanism to shift the environmental and financial burden of end‐of‐life products from public management to producers. Recently, EPR has been adopted by a growing number of developing countries, but this policy often struggles in being effectively implemented in such contexts, missing the opportunity of using waste management as a sustainability driver. By discussing the EPR for end‐of‐life tires (ELTs) in Ecuador, this paper proposes a different approach in designing and implementing EPR schemes in developing countries: it recommends consideration of social sustainability, rather than merely copying foreign management frameworks. To address this point, two case studies on socially directed ELT applications were designed and carried out. The case studies aimed at improving resilience of vulnerable populations to natural disasters by increasing the resistance of housing and settlements against catastrophic events using civil engineering applications. The analysis of the case studies’ outcomes brings to light possible policy adjustments, in which social sustainability goals are taken into account within the national EPR scheme. The Ecuadorian case also highlights the benefit of employing an adaptive governance approach when dealing with challenging urban management topics, such as informality (a widespread phenomenon in developing countries) and resilience.     

Genome‐wide variation in DNA methylation is associated with stress resilience and plumage brightness in a wild bird

Individuals often differ in their ability to cope with challenging environmental and social conditions. Evidence from model systems suggests that patterns of DNA methylation are associated with variation in coping ability. These associations could arise directly if methylation plays a role in controlling the physiological response to stressors by, among other things, regulating the release of glucocorticoids in response to challenges. Alternatively, the association could arise indirectly if methylation and resilience have a common cause, such as early‐life conditions. In either case, methylation might act as a biomarker for coping ability. At present, however, relatively little is known about whether variation in methylation is associated with organismal performance and resilience under natural conditions. We studied genome‐wide patterns of DNA methylation in free‐living female tree swallows (Tachycineta bicolor) using methylated DNA immunoprecipitation (MeDIP) and a tree swallow genome that was assembled for this study. We identified areas of the genome that were differentially methylated with respect to social signal expression (breast brightness) and physiological traits (ability to terminate the glucocorticoid stress response through negative feedback). We also asked whether methylation predicted resilience to a subsequent experimentally imposed challenge. Individuals with brighter breast plumage and higher stress resilience had lower methylation at differentially methylated regions across the genome. Thus, widespread differences in methylation predicted both social signal expression and the response to future challenges under natural conditions. These results have implications for predicting individual differences in resilience, and for understanding the mechanistic basis of resilience and its environmental and social mediators.     

Functional diversity can facilitate the collapse of an undesirable ecosystem state

Biodiversity may increase ecosystem resilience. However, we have limited understanding if this holds true for ecosystems that respond to gradual environmental change with abrupt shifts to an alternative state. We used a mathematical model of anoxic–oxic regime shifts and explored how trait diversity in three groups of bacteria influences resilience. We found that trait diversity did not always increase resilience: greater diversity in two of the groups increased but in one group decreased resilience of their preferred ecosystem state. We also found that simultaneous trait diversity in multiple groups often led to reduced or erased diversity effects. Overall, our results suggest that higher diversity can increase resilience but can also promote collapse when diversity occurs in a functional group that negatively influences the state it occurs in. We propose this mechanism as a potential management approach to facilitate the recovery of a desired ecosystem state.     

Fine-scale population genetic structure in a fission-fusion society

Nonrandom patterns of mating and dispersal create fine-scale genetic structure in natural populations — especially of social mammals — with important evolutionary and conservation genetic consequences. Such structure is well-characterized for typical mammalian societies; that is, societies where social group composition is stable, dispersal is male-biased, and males form permanent breeding associations in just one or a few social groups over the course of their lives. However, genetic structure is not well understood for social mammals that differ from this pattern, including elephants. In elephant societies, social groups fission and fuse, and males never form permanent breeding associations with female groups. Here, we combine 33 years of behavioural observations with genetic information for 545 African elephants ( Loxodonta africana ), to investigate how mating and dispersal behaviours structure genetic variation between social groups and across age classes. We found that, like most social mammals, female matrilocality in elephants creates co-ancestry within core social groups and significant genetic differentiation between groups (Φ_ST = 0.058). However, unlike typical social mammals, male elephants do not bias reproduction towards a limited subset of social groups, and instead breed randomly across the population. As a result, reproductively dominant males mediate gene flow between core groups, which creates cohorts of similar-aged paternal relatives across the population. Because poaching tends to eliminate the oldest elephants from populations, illegal hunting and poaching are likely to erode fine-scale genetic structure. We discuss our results and their evolutionary and conservation genetic implications in the context of other social mammals.     

External shocks,agent interactions,and endogenous feedbacks — Investigating system resilience with a stylized land use model

Dynamics of coupled Social-Ecological Systems (SES) result from the interplay of society and ecology. To assess SES resilience, we constructed an Agent-Based Model (ABM) of a land use system as a stereotypical example of SES and investigated how resilience of the represented system is affected by both external disturbances and internal dynamics. The model explicitly considered different aspects of resilience in a framework derived from literature, which includes “resilience to”, “resilience of”, “resilience at”, “resilience due to”, and “indicators of resilience”. External disturbances were implemented as shocks in crop yields. Internal dynamics comprised of two types of social interaction between agents (learning and cooperation), an ecological feedback of soil depletion and an economic feedback of agglomeration benefits. We systematically varied these mechanisms and measured indicators that reflected spatial, social, and economic resilience. Results showed that (1) internal mechanisms increased the ability of the system to recover from external shocks, (2) feedbacks resulted in different regimes of crop cultivation, each with a distinctive set of functions, and (3) resilience is not a generic system property, but strongly depends on what system function is considered. We recommend future studies to include internal dynamics, especially feedbacks, and to systematically assess them across different aspects of resilience.     

Evolutionary precursors of social norms in chimpanzees: a new approach

Moral behaviour, based on social norms, is commonly regarded as a hallmark of humans. Hitherto, humans are perceived to be the only species possessing social norms and to engage in moral behaviour. There is anecdotal evidence suggesting their presence in chimpanzees, but systematic studies are lacking. Here, we examine the evolution of human social norms and their underlying psychological mechanisms. For this, we distinguish between conventions, cultural social norms and universal social norms. We aim at exploring whether chimpanzees possess evolutionary precursors of universal social norms seen in humans. Chimpanzees exhibit important preconditions for their presence and enforcement: tolerant societies, well-developed social-cognitive skills and empathetic competence. Here, we develop a theoretical framework for recognizing different functional levels of social norms and distinguish them from mere statistical behavioural regularities. Quasi social norms are found where animals behave functionally moral without having moral emotions. In proto social norms, moral emotions might be present but cannot be collectivized due to the absence of a uniquely human psychological trait, i.e. shared intentionality. Human social norms, whether they are universal or cultural, involve moral emotions and are collectivized. We will discuss behaviours in chimpanzees that represent potential evolutionary precursors of human universal social norms, with special focus on social interactions involving infants. We argue that chimpanzee infants occupy a special status within their communities and propose that tolerance towards them might represent a proto social norm. Finally, we discuss possible ways to test this theoretical framework.     

The complex structure of hunter-gatherer social networks

In nature, many different types of complex system form hierarchical, self-similar or fractal-like structures that have evolved to maximize internal efficiency. In this paper, we ask whether hunter-gatherer societies show similar structural properties. We use fractal network theory to analyse the statistical structure of 1189 social groups in 339 hunter-gatherer societies from a published compilation of ethnographies. We show that population structure is indeed self-similar or fractal-like with the number of individuals or groups belonging to each successively higher level of organization exhibiting a constant ratio close to 4. Further, despite the wide ecological, cultural and historical diversity of hunter-gatherer societies, this remarkable self-similarity holds both within and across cultures and continents. We show that the branching ratio is related to density-dependent reproduction in complex environments and hypothesize that the general pattern of hierarchical organization reflects the self-similar properties of the networks and the underlying cohesive and disruptive forces that govern the flow of material resources, genes and non-genetic information within and between social groups. Our results offer insight into the energetics of human sociality and suggest that human social networks self-organize in response to similar optimization principles found behind the formation of many complex systems in nature.     

Female social dynamics in a provisioned free-ranging band of the Sichuan snub-nosed monkey (Rhinopithecus roxellana) in the Qinling Mountains, China

Little information is available on the social dynamics of the Sichuan snub-nosed monkeys (Rhinopithecus roxellana). Here, we provide 5-year observational data on a provisioned free-ranging band in the Qinling Mountains, central China, from October 2001 to December 2005. The results of this study suggested that females place a high priority on maintaining long-term relationships with other female in their one-male units (OMUs). Females had more social interactions with unit members than with nonunit individuals. They showed relatively high rates of affiliation with their unit females, intermediate levels with the resident males, and low levels with individuals outside the unit. Females had few interactions with other resident males. Social interactions, especially affiliative interactions, were more symmetrical between focal females and their unit females than between focal females and the resident males. Thus female social interactions appeared to resemble those of other female-bonded primate societies. On the other hand, female transfers occurred sometimes. We recorded 11 cases of female immigration and 5 cases of female disappearance, 1 case of female intraband shift, and 2 cases of "merging of OMUs," which suggested that unit females might be loose-knit in this species. We discussed influencing factors on female Sichuan snub-nosed monkey social dynamics, by comparing them with those of Hamadryas and gelada baboons that also have multilevel societies.