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Riris P, Silva F, Crema E, Palmisano A, Robinson E, Siegel PE, French JC, Jørgensen EK, Maezumi SY, Solheim S, Bates J, Davies B, Oh Y, Ren X. Frequent disturbances enhanced the resilience of past human populations. Nature 2024; 629:837-842. [PMID: 38693262 PMCID: PMC11111401 DOI: 10.1038/s41586-024-07354-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 03/26/2024] [Indexed: 05/03/2024]
Abstract
The record of past human adaptations provides crucial lessons for guiding responses to crises in the future1-3. To date, there have been no systematic global comparisons of humans' ability to absorb and recover from disturbances through time4,5. Here we synthesized resilience across a broad sample of prehistoric population time-frequency data, spanning 30,000 years of human history. Cross-sectional and longitudinal analyses of population decline show that frequent disturbances enhance a population's capacity to resist and recover from later downturns. Land-use patterns are important mediators of the strength of this positive association: farming and herding societies are more vulnerable but also more resilient overall. The results show that important trade-offs exist when adopting new or alternative land-use strategies.
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Affiliation(s)
- Philip Riris
- Department of Archaeology and Anthropology, Bournemouth University, Poole, UK.
| | - Fabio Silva
- Department of Archaeology and Anthropology, Bournemouth University, Poole, UK
| | - Enrico Crema
- Department of Archaeology, University of Cambridge, Cambridge, UK
| | - Alessio Palmisano
- Department of Historical Studies, University of Turin, Torino, Italy
| | - Erick Robinson
- Native Environment Solutions, Boise, ID, USA
- Division of Atmospheric Sciences, Desert Research Institute, Reno, NV, USA
- School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA
| | - Peter E Siegel
- Department of Anthropology, Montclair State University, Montclair, NJ, USA
| | - Jennifer C French
- Department of Archaeology, Classics, and Egyptology, University of Liverpool, Liverpool, UK
| | | | - Shira Yoshi Maezumi
- Department of Archaeology, Max Planck Institute of Geoanthropology, Jena, Germany
| | - Steinar Solheim
- The Museum of Cultural History, University of Oslo, Oslo, Norway
| | - Jennifer Bates
- Department of Archaeology and Art History, Seoul National University, Seoul, Republic of Korea
| | | | - Yongje Oh
- Department of Archaeology and Art History, Seoul National University, Seoul, Republic of Korea
| | - Xiaolin Ren
- Institute for the History of Natural Sciences, Chinese Academy of Sciences, Beijing, People's Republic of China
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2
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Galeta P, Pankowská A. A new method for estimating growth and fertility rates using age-at-death ratios in small skeletal samples: The effect of mortality and stochastic variation. PLoS One 2023; 18:e0286580. [PMID: 37267306 DOI: 10.1371/journal.pone.0286580] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Accepted: 05/18/2023] [Indexed: 06/04/2023] Open
Abstract
The common procedure for reconstructing growth and fertility rates from skeletal samples involves regressing a growth or fertility rate on the age-at-death ratio, an indicator that captures the proportion of children and juveniles in a skeletal sample. Current methods derive formulae for predicting growth and fertility rates in skeletal samples from modern reference populations with many deaths, although recent levels of mortality are not good proxies for prehistoric populations, and stochastic error may considerably affect the age distributions of deaths in small skeletal samples. This study addresses these issues and proposes a novel algorithm allowing a customized prediction formula to be produced for each target skeletal sample, which increases the accuracy of growth and fertility rate estimation. Every prediction equation is derived from a unique reference set of simulated skeletal samples that match the target skeletal sample in size and assumed mortality level of the population that the target skeletal sample represents. The mortality regimes of reference populations are based on model life tables in which life expectancy can be flexibly set between 18 and 80 years. Regression models provide a reliable prediction; the models explain 83-95% of total variance. Due to stochastic variation, the prediction error is large when the estimate is based on a small number of skeletons but decreases substantially with increasing sample size. The applicability of our approach is demonstrated by a comparison with baseline estimates, defined here as predictions based on the widely used Bocquet-Appel (2002, doi: 10.1086/342429) equation.
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Affiliation(s)
- Patrik Galeta
- Department of Anthropology, University of West Bohemia, Pilsen, Czech Republic
| | - Anna Pankowská
- Department of Anthropology, University of West Bohemia, Pilsen, Czech Republic
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Taylor BR, Oxenham M, McFadden C. Estimating fertility using adults: A method for under-enumerated pre-adult skeletal samples. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023; 181:262-270. [PMID: 36974969 DOI: 10.1002/ajpa.24739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 01/20/2023] [Accepted: 03/13/2023] [Indexed: 05/18/2023]
Abstract
OBJECTIVES Infant underrepresentation poses a great risk to accurate palaeodemographic findings when analyzing skeletal samples. Empirically derived palaeodemographic methods all require unbiased or minimally biased pre-adult representation for estimating demographic characteristics, including fertility. Currently, there are no reliable methods for estimating palaeodemographic parameters when pre-adults are underrepresented in skeletal samples, consequently such samples are often excluded from palaeodemographic analyses. The aim of this article is to develop a method for estimating total fertility rate (TFR) using reproductive aged adults, specifically for samples with suspected pre-adult under-enumeration. METHODOLOGY United Nations mortality data and TFR from the World Population Prospects was utilized. The correlation between known fertility and the proportion of individuals in key reproductive years (15-49 years) to total adult sample (15+ years) was assessed as an indirect means to estimate fertility. RESULTS It was determined that the proportion of reproductive aged adults is a reasonable proxy for fertility. A significant positive correlation was observed between the TFR and those who died aged 15-49 years of age as a proportion of those who died ≥15 years (D15-49/D15+). SE of the estimate revealed reasonable predictive accuracy. When applied to two modern non-agricultural populations, the method showed some variability in accuracy but good potential for an improved outcome over existing methods when pre-adults are underrepresented. CONCLUSION This research has provided a new method for estimating fertility in archeological skeletal samples with pre-adult under-enumeration. In combination with a contextually focused approach, this provides a significant step toward further use of biased samples in palaeodemography.
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Affiliation(s)
- Bonnie R Taylor
- School of Archaeology and Anthropology, Australian National University, Canberra, ACT 2601, Australia
| | - Marc Oxenham
- School of Archaeology and Anthropology, Australian National University, Canberra, ACT 2601, Australia
- Department of Archaeology, School of Geosciences, University of Aberdeen, Aberdeen, UK
| | - Clare McFadden
- School of Archaeology and Anthropology, Australian National University, Canberra, ACT 2601, Australia
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Changes in limiting factors for forager population dynamics in Europe across the last glacial-interglacial transition. Nat Commun 2022; 13:5140. [PMID: 36068206 PMCID: PMC9448755 DOI: 10.1038/s41467-022-32750-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Accepted: 08/16/2022] [Indexed: 11/09/2022] Open
Abstract
Population dynamics set the framework for human genetic and cultural evolution. For foragers, demographic and environmental changes correlate strongly, although the causal relations between different environmental variables and human responses through time and space likely varied. Building on the notion of limiting factors, namely that at any one time, the scarcest resource caps population size, we present a statistical approach to identify the dominant climatic constraints for hunter-gatherer population densities and then hindcast their changing dynamics in Europe for the period between 21,000 to 8000 years ago. Limiting factors shifted from temperature-related variables (effective temperature) during the Pleistocene to a regional mosaic of limiting factors in the Holocene dominated by temperature seasonality and annual precipitation. This spatiotemporal variation suggests that hunter-gatherers needed to overcome very different adaptive challenges in different parts of Europe and that these challenges varied over time. The signatures of these changing adaptations may be visible archaeologically. In addition, the spatial disaggregation of limiting factors from the Pleistocene to the Holocene coincided with and may partly explain the diversification of the cultural geography at this time. Here, the authors use climate and resource availability, to statistically model the limiting factors in the dynamics of hunter-gatherer population densities in Europe between 21,000 and 8,000 years ago. They find that limiting factors varied spatiotemporally and the effects of these may be visible in the archaeological record.
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Boldsen JL, Milner GR, Ousley SD. Paleodemography: From archaeology and skeletal age estimation to life in the past. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2022; 178 Suppl 74:115-150. [PMID: 36787786 DOI: 10.1002/ajpa.24462] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 11/09/2021] [Accepted: 11/22/2021] [Indexed: 12/14/2022]
Abstract
Much of paleodemography, an interdisciplinary field with strong ties to archaeology, among other disciplines, is oriented toward clarifying the life experiences of past people and why they changed over time. We focus on how human skeletons contribute to our understanding of preindustrial demographic regimes, including when changes took place that led to the world as we know it today. Problems with existing paleodemographic practices are highlighted, as are promising directions for future work. The latter requires both better age estimates and innovative methods to handle data appropriately. Age-at-death estimates for adult skeletons are a particular problem, especially for adults over 50 years that undoubtedly are mistakenly underrepresented in published studies of archaeological skeletons. Better age estimates for the entirety of the lifespan are essential to generate realistic distributions of age at death. There are currently encouraging signs that after about a half-century of intensive, and sometimes contentious, research, paleodemography is poised to contribute much to understandings of evolutionary processes, the structure of past populations, and human-disease interaction, among other topics.
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Affiliation(s)
- Jesper L Boldsen
- ADBOU, University of Southern Denmark, Campusvej 55, Odense M, Denmark
| | - George R Milner
- Department of Anthropology, The Pennsylvania State University, University Park, Pennsylvania, USA
| | - Stephen D Ousley
- Department of Anthropology, University of Tennessee, Knoxville, Tennessee, USA
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Riris P, de Souza JG. Formal Tests for Resistance-Resilience in Archaeological Time Series. Front Ecol Evol 2021. [DOI: 10.3389/fevo.2021.740629] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The study of resilience is a common pathway for scientific data to inform policy and practice towards impending climate change. Consequently, understanding the mechanisms and features that contribute towards building resilience is a key goal of much research on coupled socio-environmental systems. In parallel, archaeology has developed the ambition to contribute to this agenda through its unique focus on cultural dynamics that occur over the very long term. This paper argues that archaeological studies of resilience are limited in scope and potential impact by incomplete operational definitions of resilience, itself a multifaceted and contested concept. This lack of interdisciplinary engagement fundamentally limits archaeology’s ability to contribute meaningfully to understanding factors behind the emergence and maintenance of long-term societal resilience, a topic of significant interest that the field is in theory ideally positioned to address. Here, we introduce resilience metrics drawn from ecology and develop case studies to illustrate their potential utility for archaeological studies. We achieve this by extending methods for formally measuring resistance, the capacity of a system to absorb disturbances; and resilience, its capacity to recover from disturbances, with a novel significance test for palaeodemographic data. Building on statistical permutation and post-hoc tests available in the rcarbon package in the R statistical environment, we apply our adapted resilience-resistance framework to summed probability distributions of calibrated radiocarbon dates drawn from the Atlantic Forest of eastern Brazil. We deploy these methods to investigate cross-sectional trends across three recognised biogeographical zones of the Atlantic Forest domain, against the backdrop of prehistoric phases of heightened hydroclimatic variability. Our analysis uncovers novel centennial-scale spatial structure in the resilience of palaeodemographic growth rates. In addition to the case-specific findings, we suggest that adapting formal metrics can help archaeology create impact and engagement beyond relatively narrow disciplinary concerns. To this end, we supply code and data to replicate our palaeodemographic analyses to enable their use and adaptation to other archaeological problems.
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Crema ER, Shoda S. A Bayesian approach for fitting and comparing demographic growth models of radiocarbon dates: A case study on the Jomon-Yayoi transition in Kyushu (Japan). PLoS One 2021; 16:e0251695. [PMID: 34010349 PMCID: PMC8133439 DOI: 10.1371/journal.pone.0251695] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 05/02/2021] [Indexed: 11/19/2022] Open
Abstract
Large sets of radiocarbon dates are increasingly used as proxies for inferring past population dynamics and the last few years, in particular, saw an increase in the development of new statistical techniques to overcome some of the key challenges imposed by this kind of data. These include: 1) null hypothesis significance testing approaches based on Monte-Carlo simulations or mark permutations; 2) non-parametric Bayesian modelling approaches, and 3) the use of more traditional techniques such as correlation, regression, and AIC-based model comparison directly on the summed probability distribution of radiocarbon dates (SPD). While the range of opportunities offered by these solutions is unquestionably appealing, they often do not consider the uncertainty and the biases arising from calibration effects or sampling error. Here we introduce a novel Bayesian approach and nimbleCarbon, an R package that offers model fitting and comparison for population growth models based on the temporal frequency data of radiocarbon dates. We evaluate the robustness of the proposed approach on a range of simulated scenarios and illustrate its application on a case study focused on the demographic impact of the introduction of wet-rice farming in prehistoric Japan during the 1st millennium BCE.
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Affiliation(s)
- Enrico R. Crema
- Department of Archaeology, University of Cambridge, Cambridge, United Kingdom
| | - Shinya Shoda
- BioArCh, University of York, Wentworth Way, Heslington, York, United Kingdom
- Nara National Research Institute for Cultural Properties, Nara, Japan
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