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Weij R, Sniderman JMK, Woodhead JD, Hellstrom JC, Brown JR, Drysdale RN, Reed E, Bourne S, Gordon J. Elevated Southern Hemisphere moisture availability during glacial periods. Nature 2024; 626:319-326. [PMID: 38326596 DOI: 10.1038/s41586-023-06989-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 12/15/2023] [Indexed: 02/09/2024]
Abstract
Late Pleistocene ice-age climates are routinely characterized as having imposed moisture stress on low- to mid-latitude ecosystems1-5. This idea is largely based on fossil pollen evidence for widespread, low-biomass glacial vegetation, interpreted as indicating climatic dryness6. However, woody plant growth is inhibited under low atmospheric CO2 (refs. 7,8), so understanding glacial environments requires the development of new palaeoclimate indicators that are independent of vegetation9. Here we show that, contrary to expectations, during the past 350 kyr, peaks in southern Australian climatic moisture availability were largely confined to glacial periods, including the Last Glacial Maximum, whereas warm interglacials were relatively dry. By measuring the timing of speleothem growth in the Southern Hemisphere subtropics, which today has a predominantly negative annual moisture balance, we developed a record of climatic moisture availability that is independent of vegetation and extends through multiple glacial-interglacial cycles. Our results demonstrate that a cool-moist response is consistent across the austral subtropics and, in part, may result from reduced evaporation under cool glacial temperatures. Insofar as cold glacial environments in the Southern Hemisphere subtropics have been portrayed as uniformly arid3,10,11, our findings suggest that their characterization as evolutionary or physiological obstacles to movement and expansion of animal, plant and, potentially, human populations10 should be reconsidered.
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Affiliation(s)
- Rieneke Weij
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia.
- Department of Geological Sciences and the Human Evolution Research Institute, University of Cape Town, Rondebosch, Western Cape, South Africa.
| | - J M Kale Sniderman
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia.
| | - Jon D Woodhead
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - John C Hellstrom
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Josephine R Brown
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
| | - Russell N Drysdale
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
- Environnements, Dynamiques et Territoires de la Montagne, UMR CNRS, Université de Savoie-Mont, Chambéry, France
| | - Elizabeth Reed
- School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia
- South Australian Museum, Adelaide, South Australia, Australia
| | - Steven Bourne
- Limestone Coast Landscape Board, Mount Gambier, South Australia, Australia
| | - Jay Gordon
- School of Geography, Earth and Atmospheric Sciences, University of Melbourne, Melbourne, Victoria, Australia
- IEEFA, Melbourne, Victoria, Australia
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Carr AS, Chase BM, Birkinshaw SJ, Holmes PJ, Rabumbulu M, Stewart BA. Paleolakes and socioecological implications of last glacial "greening" of the South African interior. Proc Natl Acad Sci U S A 2023; 120:e2221082120. [PMID: 37186818 PMCID: PMC10214169 DOI: 10.1073/pnas.2221082120] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2022] [Accepted: 04/03/2023] [Indexed: 05/17/2023] Open
Abstract
Determining the timing and drivers of Pleistocene hydrological change in the interior of South Africa is critical for testing hypotheses regarding the presence, dynamics, and resilience of human populations. Combining geological data and physically based distributed hydrological modeling, we demonstrate the presence of large paleolakes in South Africa's central interior during the last glacial period, and infer a regional-scale invigoration of hydrological networks, particularly during marine isotope stages 3 and 2, most notably 55 to 39 ka and 34 to 31 ka. The resulting hydrological reconstructions further permit investigation of regional floral and fauna responses using a modern analog approach. These suggest that the climate change required to sustain these water bodies would have replaced xeric shrubland with more productive, eutrophic grassland or higher grass-cover vegetation, capable of supporting a substantial increase in ungulate diversity and biomass. The existence of such resource-rich landscapes for protracted phases within the last glacial period likely exerted a recurrent draw on human societies, evidenced by extensive pan-side artifact assemblages. Thus, rather than representing a perennially uninhabited hinterland, the central interior's underrepresentation in late Pleistocene archeological narratives likely reflects taphonomic biases stemming from a dearth of rockshelters and regional geomorphic controls. These findings suggest that South Africa's central interior experienced greater climatic, ecological, and cultural dynamism than previously appreciated and potential to host human populations whose archaeological signatures deserve systematic investigation.
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Affiliation(s)
- Andrew S. Carr
- School of Geography, Geology and the Environment, University of Leicester, LeicesterLE1 7RH, United Kingdom
| | - Brian M. Chase
- Institut des Sciences de L'Evolution-Montpellier, University of Montpellier, Centre National de la Recherche Scientifique, École Pratique des Hautes Études, Institut de Recherche pour le Développement,34095Montpellier, France
- Department of Environmental and Geographical Science, University of Cape Town, Rondebosch7701, South Africa
| | - Stephen J. Birkinshaw
- School of Engineering, Newcastle University, Newcastle upon TyneNE1 7RU, United Kingdom
| | - Peter J. Holmes
- Department of Geography, University of the Free State, Bloemfontein9300, South Africa
| | - Mulalo Rabumbulu
- Department of Geography Environmental Management and Energy Studies, University of Johannesburg, Johannesburg2006, South Africa
| | - Brian A. Stewart
- Department of Anthropology and Museum of Anthropological Archaeology, University of Michigan, Ann Arbor, MI48109
- Rock Art Research Institute, University of the Witwatersrand, 2050Wits, South Africa
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Val A, Collins B. From Veld to Coast: Towards an Understanding of the Diverse Landscapes' Uses by Past Foragers in Southern Africa. JOURNAL OF PALEOLITHIC ARCHAEOLOGY 2022; 5:16. [PMID: 36406469 PMCID: PMC9660208 DOI: 10.1007/s41982-022-00124-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Accepted: 10/07/2022] [Indexed: 06/16/2023]
Abstract
In this brief contribution, we outline the aims of a collection entitled "From veld to coast: towards an understanding of the diverse landscapes' uses by past foragers in southern Africa," and we define its chronological, geographic and thematic framework.
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Affiliation(s)
- Aurore Val
- Abteilung Für Ältere Urgeschichte Und Quartärökologie, Universität Tübingen, Tübingen, Germany
- Interdisciplinary Center for Archaeology and the Evolution of Human Behavior (ICArEHB), Universidade Do Algarve, Faro, Portugal
| | - Benjamin Collins
- Department of Anthropology, University of Manitoba, Winnipeg, Canada
- Department of Archaeology, University of Cape Town, Cape Town, South Africa
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