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GenT Researchers reconstruct the demographic dynamics of the last hunter-gatherer populations of Portugal during the Pleistocene-Holocene

GenT Researchers reconstruct the demographic dynamics of the last hunter-gatherer populations of Portugal during the Pleistocene-Holocene

 

Carried out by researchers from the University of Alicante (Spain) and the University of Algarve (Portugal), the study confirms that they adapted very well to the 8.2 climate event in which the global temperature of the planet dropped by about 2ºC, reorganizing the distribution of their settlements and exploiting more intensively the aquatic resources of the Tagus and Sado rivers.

A study carried out by researchers from the University of Alicante (Spain) and the University of Algarve (Portugal) reveals the demographic changes of the last hunter-gatherer populations in Portugal during the Pleistocene-Holocene transition, between 18,000 and 8,000 years ago. Published in the prestigious scientific journal Philosophical Transactions of the Royal Society B, this work has great implications for the study of population adaptations to climate change.
 
Specifically, the scientific team has analyzed Carbon 14 dating (a radiocarbon dating technique to measure the age of archaeological remains) to reconstruct the relative changes in population size and analyze its relationship with changes in diet and in settlement systems during this period characterized by major climatic changes and environmental transformations.
 
"The article has great implications for knowing how hunter-gatherer populations adapted to climate change by modifying the way they occupy the territory and the diet", indicates Javier Fernández-López de Pablo, author of the article and distinguished researcher of the Gen- T attached to the University Institute for Research in Archeology and Historical Heritage (INAPH) of the University of Alicante. The experts present a complete reconstruction of the demographic dynamics during the end of the last ice age and the beginning of the Holocene in the Atlantic façade of the Iberian Peninsula, a space in which the last populations of hunter-gatherers faced environments and climatic conditions rapidly changing. In this sense, this archaeological study offers a perspective on how the ecologies of the human population of the past changed in response to this scenario.
 
Results
 
Researchers have identified a first phase of population growth during the late Pleistocene interstadial period (about 14,800 years ago) and the beginnings of the recent Dryas cold weather episode (12,800 years ago). This latest episode of climatic deterioration seems to be associated with a contraction in the size of the population whose territorial distribution would show a more dispersed pattern.
 
On the other hand, the study indicates a last phase of population growth that begins about 8,300 years ago, coinciding with the climatic event of 8.2 in which the global temperature of the planet dropped by 2ºC, and the change in marine currents increased biological productivity. in the estuaries of the main rivers Tagus and Sado. "The settlers began to concentrate around these spaces, which allowed a more intense exploitation of aquatic resources, as well as a rapid population growth," explains the distinguished UA researcher.
 
As detailed by Fernández-López de Pablo, unlike what has been observed in other regions of the Iberian Peninsula, this case study shows a strong correlation between population growth and the changes in marine productivity observed in estuaries. "These populations were able to generate successful adaptive responses both in diet and settlement pattern during the Mesolithic period, around 8,300 years ago, and due to a greater dependence on marine food sources," he adds.
 
Methodology
 
The team of researchers who have authored this article have worked for 2 years in the analysis and study of data from around 70 prehistoric sites distributed throughout the Atlantic coast, more than 370 radiocarbon dates, and from human remains to obtain information on Paleo Diet. "Without a doubt it is the first scientific study focused on the Atlantic slope of the Iberian Peninsula that contemplates such a long period of time", highlights the UA expert. In addition, he adds, "we have developed new quantitative methods to create time series with which to trace changes over time in population size, population distribution and changes in diet."
 
Reference:
 
"Late Glacial and Early Holocene human demographic responses to climatic and environmental change in Atlantic Iberia", Philosophical Transactions of the Royal Society B. November 2020.