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Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene

The termination of the African Humid Period in northeastern Africa during the early Holocene was marked by the southward migration of the rain belt and the disappearance of the Green Sahara. This interval of drastic environmental changes was also marked by the initiation of food production by North...

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Detalles Bibliográficos
Autores principales: Blanchet, Cécile L., Frank, Martin, Schouten, Stefan
Formato: Online Artículo Texto
Lenguaje:English
Publicado: Public Library of Science 2014
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4281134/
https://www.ncbi.nlm.nih.gov/pubmed/25551633
http://dx.doi.org/10.1371/journal.pone.0115958
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author Blanchet, Cécile L.
Frank, Martin
Schouten, Stefan
author_facet Blanchet, Cécile L.
Frank, Martin
Schouten, Stefan
author_sort Blanchet, Cécile L.
collection PubMed
description The termination of the African Humid Period in northeastern Africa during the early Holocene was marked by the southward migration of the rain belt and the disappearance of the Green Sahara. This interval of drastic environmental changes was also marked by the initiation of food production by North African hunter-gatherer populations and thus provides critical information on human-environment relationships. However, existing records of regional climatic and environmental changes exhibit large differences in timing and modes of the wet/dry transition at the end of the African Humid Period. Here we present independent records of changes in river runoff, vegetation and erosion in the Nile River watershed during the Holocene obtained from a unique sedimentary sequence on the Nile River fan using organic and inorganic proxy data. This high-resolution reconstruction allows to examine the phase relationship between the changes of these three parameters and provides a detailed picture of the environmental conditions during the Paleolithic/Neolithic transition. The data show that river runoff decreased gradually during the wet/arid transition at the end of the AHP whereas rapid shifts of vegetation and erosion occurred earlier between 8.7 and ∼6 ka BP. These asynchronous changes are compared to other regional records and provide new insights into the threshold responses of the environment to climatic changes. Our record demonstrates that the degradation of the environment in northeastern Africa was more abrupt and occurred earlier than previously thought and may have accelerated the process of domestication in order to secure sustainable food resources for the Neolithic African populations.
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spelling pubmed-42811342015-01-07 Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene Blanchet, Cécile L. Frank, Martin Schouten, Stefan PLoS One Research Article The termination of the African Humid Period in northeastern Africa during the early Holocene was marked by the southward migration of the rain belt and the disappearance of the Green Sahara. This interval of drastic environmental changes was also marked by the initiation of food production by North African hunter-gatherer populations and thus provides critical information on human-environment relationships. However, existing records of regional climatic and environmental changes exhibit large differences in timing and modes of the wet/dry transition at the end of the African Humid Period. Here we present independent records of changes in river runoff, vegetation and erosion in the Nile River watershed during the Holocene obtained from a unique sedimentary sequence on the Nile River fan using organic and inorganic proxy data. This high-resolution reconstruction allows to examine the phase relationship between the changes of these three parameters and provides a detailed picture of the environmental conditions during the Paleolithic/Neolithic transition. The data show that river runoff decreased gradually during the wet/arid transition at the end of the AHP whereas rapid shifts of vegetation and erosion occurred earlier between 8.7 and ∼6 ka BP. These asynchronous changes are compared to other regional records and provide new insights into the threshold responses of the environment to climatic changes. Our record demonstrates that the degradation of the environment in northeastern Africa was more abrupt and occurred earlier than previously thought and may have accelerated the process of domestication in order to secure sustainable food resources for the Neolithic African populations. Public Library of Science 2014-12-31 /pmc/articles/PMC4281134/ /pubmed/25551633 http://dx.doi.org/10.1371/journal.pone.0115958 Text en © 2014 Blanchet et al http://creativecommons.org/licenses/by/4.0/ This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are properly credited.
spellingShingle Research Article
Blanchet, Cécile L.
Frank, Martin
Schouten, Stefan
Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene
title Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene
title_full Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene
title_fullStr Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene
title_full_unstemmed Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene
title_short Asynchronous Changes in Vegetation, Runoff and Erosion in the Nile River Watershed during the Holocene
title_sort asynchronous changes in vegetation, runoff and erosion in the nile river watershed during the holocene
topic Research Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4281134/
https://www.ncbi.nlm.nih.gov/pubmed/25551633
http://dx.doi.org/10.1371/journal.pone.0115958
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