scholarly journals Climatic changes cause synchronous population dynamics and adaptive strategies among coastal hunter-gatherers in Holocene northern Europe

2020 ◽  
pp. 1-16 ◽  
Author(s):  
Erlend Kirkeng Jørgensen ◽  
Petro Pesonen ◽  
Miikka Tallavaara

Abstract Synchronized demographic and behavioral patterns among distinct populations is a well-known, natural phenomenon. Intriguingly, similar patterns of synchrony occur among prehistoric human populations. However, the drivers of synchronous human ecodynamics are not well understood. Addressing this issue, we review the role of environmental variability in causing human demographic and adaptive responses. As a case study, we explore human ecodynamics of coastal hunter-gatherers in Holocene northern Europe, comparing population, economic, and environmental dynamics in two separate areas (northern Norway and western Finland). Population trends are reconstructed using temporal frequency distributions of radiocarbon-dated and shoreline-dated archaeological sites. These are correlated to regional environmental proxies and proxies for maritime resource use. The results demonstrate remarkably synchronous patterns across population trajectories, marine resource exploitation, settlement pattern, and technological responses. Crucially, the population dynamics strongly correspond to significant environmental changes. We evaluate competing hypotheses and suggest that the synchrony stems from similar responses to shared environmental variability. We take this to be a prehistoric human example of the “Moran effect,” positing similar responses of geographically distinct populations to shared environmental drivers. The results imply that intensified economies and social interaction networks have limited impact on long-term hunter-gatherer population trajectories beyond what is already proscribed by environmental drivers.

2020 ◽  
Author(s):  
Xintong Chen ◽  
Xianglan Li

<p>Adélie penguin (Pygoscelis adeliae) are known as an eco-indicator species of the Southern Ocean marine ecosystem. Environmental variability drives penguin population dynamics through its effects on vital rates (e.g., survival, dispersal, or breeding success). Recent studies suggested that inter-annual variation strongly affected Adélie penguin abundance in individual colonies, and aggregating abundance across space provided more reliable trends of population dynamics. By considering the similarity of the regional sea-ice concentration, we divided the Ross Sea region into six areas to investigate the effects of environmental changes on penguin population dynamics from 1982–2013. Time lagged analysis of 0–6 years between penguin abundance and environmental factors were conducted in our study. We found that penguin abundance was significantly correlated with environmental factors at different lag times (p <0.05). In the western Ross Sea region, penguin abundance was positively correlated with temperature over the past 5 years (p <0.05), and positively correlated with sea-ice concentration at a lag of 4–6 years (p <0.05). In the northernmost region of the Ross Sea, penguin abundance was significantly correlated with chlorophyll concentration 4 years earlier (p <0.01). Generalized additive model (GAM) results showed that in mid-Victoria Land, the relationship between sea-ice concentration and penguin abundance was quadratic. Penguin abundance peaked when sea-ice concentration was approximately 40%. On Franklin Island, temperature positively affected penguin abundance when temperature was lower than -3°C, and the contribution decreased considerably when temperature was higher than -2.5°C. Optimal ranges of environmental factors for Adélie penguin population might exist and differ spatially in the Ross Sea. Our study highlighted the lagged response of penguin population to environmental factors to further understand the effects of climate changes on the Antarctic biosphere.</p>


2021 ◽  
Author(s):  
Alejandro Ordonez ◽  
Felix Riede

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 the scarcest resource regulates 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 20kyBP to 8kyBP. Limiting factors shifted from temperature-related variables during the Pleistocene to a regional mosaic of limiting factors in the Holocene. This spatiotemporal variation suggests that hunter-gatherers needed to overcome very different adaptive challenges in different parts of Europe, and that these challenges vary 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 coincides with and may partly explain the diversification of the cultural geography at this time.


2020 ◽  
Vol 37 (9) ◽  
pp. 2691-2698 ◽  
Author(s):  
Xiaoming Liu

Abstract The prehistoric demography of human populations is an essential piece of information for illustrating our evolution. Despite its importance and the advancement of ancient DNA studies, our knowledge of human evolution is still limited, which is also the case for relatively recent population dynamics during and around the Holocene. Here, we inferred detailed demographic histories from 1 to 40 ka for 24 population samples using an improved model-flexible method with 36 million genome-wide noncoding CpG sites. Our results showed many population growth events that were likely due to the Neolithic Revolution (i.e., the shift from hunting and gathering to agriculture and settlement). Our results help to provide a clearer picture of human prehistoric demography, confirming the significant impact of agriculture on population expansion, and provide new hypotheses and directions for future research.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Mahdi Aminikhah ◽  
Jukka T. Forsman ◽  
Esa Koskela ◽  
Tapio Mappes ◽  
Jussi Sane ◽  
...  

AbstractZoonotic diseases, caused by pathogens transmitted between other vertebrate animals and humans, pose a major risk to human health. Rodents are important reservoir hosts for many zoonotic pathogens, and rodent population dynamics affect the infection dynamics of rodent-borne diseases, such as diseases caused by hantaviruses. However, the role of rodent population dynamics in determining the infection dynamics of rodent-associated tick-borne diseases, such as Lyme borreliosis (LB), caused by Borrelia burgdorferi sensu lato bacteria, have gained limited attention in Northern Europe, despite the multiannual abundance fluctuations, the so-called vole cycles, that characterise rodent population dynamics in the region. Here, we quantify the associations between rodent abundance and LB human cases and Puumala Orthohantavirus (PUUV) infections by using two time series (25-year and 9-year) in Finland. Both bank vole (Myodes glareolus) abundance as well as LB and PUUV infection incidence in humans showed approximately 3-year cycles. Without vector transmitted PUUV infections followed the bank vole host abundance fluctuations with two-month time lag, whereas tick-transmitted LB was associated with bank vole abundance ca. 12 and 24 months earlier. However, the strength of association between LB incidence and bank vole abundance ca. 12 months before varied over the study years. This study highlights that the human risk to acquire rodent-borne pathogens, as well as rodent-associated tick-borne pathogens is associated with the vole cycles in Northern Fennoscandia, yet with complex time lags.


Erdkunde ◽  
2021 ◽  
Vol 75 (2) ◽  
pp. 87-104
Author(s):  
Nicola Di Cosmo ◽  
Sebastian Wagner ◽  
Ulf Büntgen

After a successful conquest of large parts of Syria in 1258 and 1259 CE, the Mongol army lost the battle of 'Ayn Jālūt against Mamluks on September 3, 1260 CE. Recognized as a turning point in world history, their sudden defeat triggered the reconfiguration of strategic alliances and geopolitical power not only in the Middle East, but also across much of Eurasia. Despite decades of research, scholars have not yet reached consensus over the causes of the Mongol reverse. Here, we revisit previous arguments in light of climate and environmental changes in the aftermath of one the largest volcanic forcings in the past 2500 years, the Samalas eruption ~1257 CE. Regional tree ring-based climate reconstructions and state-of-the-art Earth System Model simulations reveal cooler and wetter conditions from spring 1258 to autumn 1259 CE for the eastern Mediterranean/Arabian region. We therefore hypothesize that the post-Samalas climate anomaly and associated environmental variability affected an estimated 120,000 Mongol soldiers and up to half a million of their horses during the conquest. More specifically, we argue that colder and wetter climates in 1258 and 1259 CE, while complicating and slowing the campaign in certain areas, such as the mountainous regions in the Caucasus and Anatolia, also facilitated the assault on Syria between January and March 1260. A return to warmer and dryer conditions in the summer of 1260 CE, however, likely reduced the regional carrying capacity and may therefore have forced a mass withdrawal of the Mongols from the region that contributed to the Mamluks’ victory. In pointing to a distinct environmental dependency of the Mongols, we offer a new explanation of their defeat at 'Ayn Jālūt, which effectively halted the further expansion of the largest ever land-based empire.


2015 ◽  
Vol 87 (3) ◽  
pp. 1717-1726 ◽  
Author(s):  
JULIANA WOJCIECHOWSKI ◽  
ANDRÉ A. PADIAL

One of the main goals of monitoring cyanobacteria blooms in aquatic environments is to reveal the relationship between cyanobacterial abundance and environmental variables. Studies typically correlate data that were simultaneously sampled. However, samplings occur sparsely over time and may not reveal the short-term responses of cyanobacterial abundance to environmental changes. In this study, we tested the hypothesis that stronger cyanobacteria x environment relationships in monitoring are found when the temporal variability of sampling points is incorporated in the statistical analyses. To this end, we investigated relationships between cyanobacteria and seven environmental variables that were sampled twice yearly for three years across 11 reservoirs, and data from an intensive monitoring in one of these reservoirs. Poor correlations were obtained when correlating data simultaneously sampled. In fact, the 'highly recurrent' role of phosphorus in cyanobacteria blooms is not properly observed in all sampling periods. On the other hand, the strongest correlation values for the total phosphorus x cyanobacteria relationship were observed when we used the variation of sampling points. We have also shown that environment variables better explain cyanobacteria when a time lag is considered. We conclude that, in cyanobacteria monitoring, the best approach to reveal determinants of cyanobacteria blooms is to consider environmental variability.


2018 ◽  
Vol 115 (47) ◽  
pp. 11988-11993 ◽  
Author(s):  
Staffan Jacob ◽  
Estelle Laurent ◽  
Bart Haegeman ◽  
Romain Bertrand ◽  
Jérôme G. Prunier ◽  
...  

Limited dispersal is classically considered as a prerequisite for ecological specialization to evolve, such that generalists are expected to show greater dispersal propensity compared with specialists. However, when individuals choose habitats that maximize their performance instead of dispersing randomly, theory predicts dispersal with habitat choice to evolve in specialists, while generalists should disperse more randomly. We tested whether habitat choice is associated with thermal niche specialization using microcosms of the ciliate Tetrahymena thermophila, a species that performs active dispersal. We found that thermal specialists preferred optimal habitats as predicted by theory, a link that should make specialists more likely to track suitable conditions under environmental changes than expected under the random dispersal assumption. Surprisingly, generalists also performed habitat choice but with a preference for suboptimal habitats. Since this result challenges current theory, we developed a metapopulation model to understand under which circumstances such a preference for suboptimal habitats should evolve. We showed that competition between generalists and specialists may favor a preference for niche margins in generalists under environmental variability. Our results demonstrate that the behavioral dimension of dispersal—here, habitat choice—fundamentally alters our predictions of how dispersal evolve with niche specialization, making dispersal behaviors crucial for ecological forecasting facing environmental changes.


2017 ◽  
Vol 10 (1) ◽  
pp. 53 ◽  
Author(s):  
Leandro Luna ◽  
Gustavo Flensborg

<p>El objetivo de este trabajo es evaluar la pertinencia de la métrica dental para obtener información sexual en individuos que habitaron el curso inferior del río Colorado durante el Holoceno tardío (ca. 3000-250 años AP), discutir el grado de dimorfismo sexual e identificar las variables cuantitativas de la dentición que permitan discriminar el sexo de nuevos individuos que se incluyan en futuros análisis. Se estudiaron las medidas máximas bucolinguales y mesiodistales del cuello de los dientes correspondientes a 26 individuos adultos. Las variables más dimórficas corresponden al diámetro bucolingual del canino superior y de ambos segundos molares; en estos casos, las diferencias entre los sexos son estadísticamente significativas. Los resultados obtenidos sobre el dimorfismo sexual se ubican en el extremo superior de los valores correspondientes a diferentes poblaciones humanas. Varios individuos que no contaban con información sexual a través de los métodos tradicionales pudieron ser clasificados desde la métrica dental, lo cual da cuenta del importante potencial de las medidas dentales para contribuir a las caracterizaciones paleodemográficas de conjuntos bioarqueológicos, especialmente en contextos perturbados y con escasa integridad esqueletal.</p><p>Palabras clave: métrica dental; determinación sexual; cazadores-recolectores; curso inferior del río Colorado; Holoceno tardío.</p><p>Abstract<br />The aim of this paper is to evaluate the relevance of dental metrics for obtaining sexual information in individuals who inhabited the lower basin of the Colorado River during the Late Holocene (ca. 3000-250 years BP), to discuss the degree of sexual dimorphism and to identify those quantitative variables adequate for sexual determination of new individuals to be included in future studies. The buccolingual and mesiodistal maximum neck diameters of 26 individual adults were studied. The most dimorphic variables correspond to the buccolingual diameter of the upper canine and both second molars; in these cases, sex differences are statistically significant. The results obtained about sexual dimorphism are located at the upper end of the range for different human populations. Several individuals who had no previous sexual information could be classified using these measurements, which accounts for the significant potential of dental metrics in palaeodemographic characterizations, especially in disturbed bioarchaeological samples.</p><p>Keywords: dental metrics; sexual determination; hunter-gatherers; lower basin of the Colorado River; Late Holocene.</p>


2020 ◽  
pp. 27-47
Author(s):  
Max D. Price

Wild boar are dangerous animals that Paleolithic peoples hunted infrequently for the first million years of human-suid contact. Projectile weapons, nets, and the domestication of dogs allowed Natufian hunter-gatherers (12,500–9700 BC) to find in wild boar a reliable source of food. By the Pre-Pottery Neolithic A (9700–8500 BC), human populations had developed close relationships with local wild boar. Intensive hunting or perhaps game management took place at Hallan Çemi in Anatolia, and the introduction of wild boar to Cyprus by at latest 9400 BC indicates the willingness of humans to capture and transport wild boar. At the same time, the presence of sedentary villages and the waste they produced likely attracted wild boar to human habitats. These early relationships between people and suids—game management and commensalism—evolved over the course of the Pre-Pottery Neolithic into full-fledged animal husbandry that, by around 7500 BC, had selected for domestic pigs.


2020 ◽  
Vol 117 (30) ◽  
pp. 18119-18126 ◽  
Author(s):  
Line S. Cordes ◽  
Daniel T. Blumstein ◽  
Kenneth B. Armitage ◽  
Paul J. CaraDonna ◽  
Dylan Z. Childs ◽  
...  

Seasonal environmental conditions shape the behavior and life history of virtually all organisms. Climate change is modifying these seasonal environmental conditions, which threatens to disrupt population dynamics. It is conceivable that climatic changes may be beneficial in one season but result in detrimental conditions in another because life-history strategies vary between these time periods. We analyzed the temporal trends in seasonal survival of yellow-bellied marmots (Marmota flaviventer) and explored the environmental drivers using a 40-y dataset from the Colorado Rocky Mountains (USA). Trends in survival revealed divergent seasonal patterns, which were similar across age-classes. Marmot survival declined during winter but generally increased during summer. Interestingly, different environmental factors appeared to drive survival trends across age-classes. Winter survival was largely driven by conditions during the preceding summer and the effect of continued climate change was likely to be mainly negative, whereas the likely outcome of continued climate change on summer survival was generally positive. This study illustrates that seasonal demographic responses need disentangling to accurately forecast the impacts of climate change on animal population dynamics.


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