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Casas-Gallego M, Hahn K, Neumann K, Demissew S, Schmidt M, Bodin SC, Bruch AA. Cooling-induced expansions of Afromontane forests in the Horn of Africa since the Last Glacial Maximum. Sci Rep 2023; 13:10323. [PMID: 37365263 DOI: 10.1038/s41598-023-37135-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 06/16/2023] [Indexed: 06/28/2023] Open
Abstract
Understanding the changing plant ecosystems that existed in East Africa over the past millennia is crucial for identifying links between habitats and past human adaptation and dispersal across the region. In the Horn of Africa, this task is hampered by the scarcity of fossil botanical data. Here we present modelled past vegetation distributions in Ethiopia from the Last Glacial Maximum (LGM) to present at high spatial and temporal resolution. The simulations show that, contrary to long-standing hypotheses, the area covered by Afromontane forests during the Late Glacial was significantly larger than at present. The combined effect of low temperatures and the relative rainfall contribution sourced from the Congo Basin and Indian Ocean, emerges as the mechanism that controlled the migration of Afromontane forests to lower elevations. This process may have enabled the development of continuous forest corridors connecting populations that are currently isolated in mountainous areas over the African continent. Starting with the Holocene, the expansion of forests began to reverse. This decline intensified over the second half of the Holocene leading to a retreat of the forests to higher elevations where they are restricted today. The simulations are consistent with proxy data derived from regional pollen records and provide a key environmental and conceptual framework for human environmental adaptation research.
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Affiliation(s)
- Manuel Casas-Gallego
- Institute of Ecology, Diversity and Evolution, Goethe University Frankfurt, Frankfurt am Main, Germany.
- Department of Geodynamics, Stratigraphy and Paleontology, Complutense University of Madrid, Madrid, Spain.
| | - Karen Hahn
- Institute of Ecology, Diversity and Evolution, Goethe University Frankfurt, Frankfurt am Main, Germany
| | - Katharina Neumann
- Department of Paleoanthropology, Senckenberg Research Institute, Frankfurt am Main, Germany
| | - Sebsebe Demissew
- National Herbarium of Ethiopia, Addis Ababa University, Addis Ababa, Ethiopia
| | - Marco Schmidt
- Palmengarten der Stadt Frankfurt am Main, Frankfurt am Main, Germany
| | - Stéphanie C Bodin
- Department of Geodynamics, Stratigraphy and Paleontology, Complutense University of Madrid, Madrid, Spain
| | - Angela A Bruch
- Research Centre "The role of culture in early expansions of humans" of the Heidelberg Academy of Sciences and Humanities, Senckenberg Research Institute, Frankfurt am Main, Germany
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2
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Gosling WD, Miller CS, Shanahan TM, Holden PB, Overpeck JT, van Langevelde F. A stronger role for long-term moisture change than for CO 2 in determining tropical woody vegetation change. Science 2022; 376:653-656. [PMID: 35511966 DOI: 10.1126/science.abg4618] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Anthropogenically elevated CO2 (eCO2) concentrations have been suggested to increase woody cover within tropical ecosystems through fertilization. The effect of eCO2 is built into Earth system models, although testing the relationship over long periods remains challenging. Here, we explore the relative importance of six drivers of vegetation change in western Africa over the past ~500,000 years (moisture availability, fire activity, mammalian herbivore density, temperature, temperature seasonality, CO2) by coupling past environmental change data from Lake Bosumtwi (Ghana) with global data. We found that moisture availability and fire activity were the most important factors in determining woody cover, whereas the effect of CO2 was small. Our findings suggest that the role of eCO2 effects on tropical vegetation in predictive models must be reconsidered.
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Affiliation(s)
- William D Gosling
- Institute for Biodiversity & Ecosystem Dynamics, University of Amsterdam, Netherlands
| | | | - Timothy M Shanahan
- Department of Geological Sciences, University of Texas at Austin, Austin, TX, USA
| | - Philip B Holden
- School of Environment, Earth & Ecosystem Sciences, The Open University, Milton Keynes, UK
| | - Jonathan T Overpeck
- School for Environment & Sustainability, University of Michigan, Ann Arbor, MI, USA
| | - Frank van Langevelde
- Department of Environmental Sciences, Wageningen University & Research, Wageningen, Netherlands.,School of Life Sciences, University of KwaZulu-Natal, KwaZulu-Natal, South Africa
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3
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Sánchez Goñi MF. Regional impacts of climate change and its relevance to human evolution. EVOLUTIONARY HUMAN SCIENCES 2020; 2:e55. [PMID: 37588361 PMCID: PMC10427484 DOI: 10.1017/ehs.2020.56] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The traditional concept of long and gradual, glacial-interglacial climate changes during the Quaternary has been challenged since the 1980s. High temporal resolution analysis of marine, terrestrial and ice geological archives has identified rapid, millennial- to centennial-scale, and large-amplitude climatic cycles throughout the last few million years. These changes were global but have had contrasting regional impacts on the terrestrial and marine ecosystems, with in some cases strong changes in the high latitudes of both hemispheres but muted changes elsewhere. Such a regionalization has produced environmental barriers and corridors that have probably triggered niche contractions/expansions of hominin populations living in Eurasia and Africa. This article reviews the long- and short-timescale ecosystem changes that have punctuated the last few million years, paying particular attention to the environments of the last 650,000 years, which have witnessed key events in the evolution of our lineage in Africa and Eurasia. This review highlights, for the first time, a contemporaneity between the split between Denisovan and Neanderthals, at ~650-400 ka, and the strong Eurasian ice-sheet expansion down to the Black Sea. This ice expansion could form an ice barrier between Europe and Asia that may have triggered the genetic drift between these two populations.
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Ivory SJ, Lézine AM, Vincens A, Cohen AS. Waxing and waning of forests: Late Quaternary biogeography of southeast Africa. GLOBAL CHANGE BIOLOGY 2018; 24:2939-2951. [PMID: 29700905 DOI: 10.1111/gcb.14150] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2017] [Revised: 03/05/2018] [Accepted: 03/09/2018] [Indexed: 06/08/2023]
Abstract
African ecosystems are at great risk. Despite their ecological and economic importance, long-standing ideas about African forest ecology and biogeography, such as the timing of changes in forest extent and the importance of disturbance, have been unable to be tested due to a lack of sufficiently long records. Here, we present the longest continuous terrestrial record of late Quaternary vegetation from southern Africa collected to date from a drill core from Lake Malawi covering the last ~600,000 years. Pollen analysis permits us to investigate changes in vegetation structure and composition over multiple climatic transitions. We observe nine phases of forest expansion and collapse related to regional hydroclimate change. The development of desert, steppe and grassland vegetation during arid periods is likely dynamically linked to thresholds in regional hydrology associated with lake level and moisture recycling. Species composition of these dryland ecosystems varied greatly and is unlike the vegetation found at Malawi today, with assemblages suggesting strong Somali-Masai affinities. Furthermore, nearly all semiarid assemblages contain low forest taxa abundances, suggesting that moist lowland gallery forests formed refugia along waterways during arid times. When the region was wet, forests were species-rich and very high afromontane tree abundances suggest frequent widespread lowland colonization by modern high elevation trees. Furthermore, species composition varied little amongst forest phases until ~80 ka when disturbance tolerant tree taxa characteristic of the modern vegetation increased in abundance. The waxing and waning of forests has important implications for understanding the processes that control modern tropical vegetation biogeography as well as the environments of early humans across Africa. Finally, this work highlights the resilience of montane forests during previous warm intervals, which is relevant for future climate change; however, we point to a fundamental shift in disturbance regimes which are crucial for the structure and composition of modern East African landscapes.
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Affiliation(s)
- Sarah J Ivory
- Department of Anthropology, Ohio State University, Columbus, OH, USA
- Department of Geosciences, Penn State University, State College, PA, USA
| | | | | | - Andrew S Cohen
- Department of Geosciences, University of Arizona, Tucson, AZ, USA
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5
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Roberts P, Gaffney D, Lee-Thorp J, Summerhayes G. Persistent tropical foraging in the highlands of terminal Pleistocene/Holocene New Guinea. Nat Ecol Evol 2017; 1:44. [DOI: 10.1038/s41559-016-0044] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 12/05/2016] [Indexed: 11/09/2022]
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Roberts P, Boivin N, Lee-Thorp J, Petraglia M, Stock J. Tropical forests and the genus Homo. Evol Anthropol 2017; 25:306-317. [PMID: 28004892 DOI: 10.1002/evan.21508] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Indexed: 11/05/2022]
Abstract
Tropical forests constitute some of the most diverse and complex terrestrial ecosystems on the planet. From the Miocene onward, they have acted as a backdrop to the ongoing evolution of our closest living relatives, the great apes, and provided the cradle for the emergence of early hominins, who retained arboreal physiological adaptations at least into the Late Pliocene. There also now exists growing evidence, from the Late Pleistocene onward, for tool-assisted intensification of tropical forest occupation and resource extraction by our own species, Homo sapiens. However, between the Late Pliocene and Late Pleistocene there is an apparent gap in clear and convincing evidence for the use of tropical forests by hominins, including early members of our own genus. In discussions of Late Pliocene and Early Pleistocene hominin evolution, including the emergence and later expansion of Homo species across the globe, tropical forest adaptations tend to be eclipsed by open, savanna environments. Thus far, it is not clear whether this Early-Middle Pleistocene lacuna in Homo-rainforest interaction is real and representative of an adaptive shift with the emergence of our species or if it is simply reflective of preservation bias.
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7
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Jump AS, Carr M, Ahrends A, Marchant R. Genetic Divergence During Long-term Isolation in Highly Diverse Populations of Tropical Trees Across the Eastern Arc Mountains of Tanzania. Biotropica 2014. [DOI: 10.1111/btp.12139] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Affiliation(s)
- Alistair S. Jump
- Tropical Ecology and Conservation Group; Biological and Environmental Sciences; School of Natural Sciences; University of Stirling; Stirling FK9 4LA U.K
| | - Martin Carr
- School of Applied Sciences; University of Huddersfield; Huddersfield HD1 3DH U.K
| | - Antje Ahrends
- Royal Botanic Garden Edinburgh; 20A Inverleith Row Edinburgh EH3 5LR U.K
| | - Rob Marchant
- York Institute for Tropical Ecosystem Dynamics; Environment Department; University of York; York YO10 5DD U.K
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Wu H, Guo Z, Guiot J, Hatté C, Peng C, Yu Y, Ge J, Li Q, Sun A, Zhao D. Elevation-induced climate change as a dominant factor causing the late Miocene C(4) plant expansion in the Himalayan foreland. GLOBAL CHANGE BIOLOGY 2014; 20:1461-1472. [PMID: 24123607 DOI: 10.1111/gcb.12426] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/04/2013] [Accepted: 08/14/2013] [Indexed: 06/02/2023]
Abstract
During the late Miocene, a dramatic global expansion of C4 plant distribution occurred with broad spatial and temporal variations. Although the event is well documented, whether subsequent expansions were caused by a decreased atmospheric CO2 concentration or climate change is a contentious issue. In this study, we used an improved inverse vegetation modeling approach that accounts for the physiological responses of C3 and C4 plants to quantitatively reconstruct the paleoclimate in the Siwalik of Nepal based on pollen and carbon isotope data. We also studied the sensitivity of the C3 and C4 plants to changes in the climate and the atmospheric CO2 concentration. We suggest that the expansion of the C4 plant distribution during the late Miocene may have been primarily triggered by regional aridification and temperature increases. The expansion was unlikely caused by reduced CO2 levels alone. Our findings suggest that this abrupt ecological shift mainly resulted from climate changes related to the decreased elevation of the Himalayan foreland.
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Affiliation(s)
- Haibin Wu
- Key Laboratory of Cenozoic Geology and Environment, Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing, 100029, China
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9
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Moncrieff GR, Scheiter S, Bond WJ, Higgins SI. Increasing atmospheric CO2 overrides the historical legacy of multiple stable biome states in Africa. THE NEW PHYTOLOGIST 2014; 201:908-915. [PMID: 24400901 DOI: 10.1111/nph.12551] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2013] [Accepted: 09/15/2013] [Indexed: 06/03/2023]
Abstract
The dominant vegetation over much of the global land surface is not predetermined by contemporary climate, but also influenced by past environmental conditions. This confounds attempts to predict current and future biome distributions, because even a perfect model would project multiple possible biomes without knowledge of the historical vegetation state. Here we compare the distribution of tree- and grass-dominated biomes across Africa simulated using a dynamic global vegetation model (DGVM). We explicitly evaluate where and under what conditions multiple stable biome states are possible for current and projected future climates. Our simulation results show that multiple stable biomes states are possible for vast areas of tropical and subtropical Africa under current conditions. Widespread loss of the potential for multiple stable biomes states is projected in the 21st Century, driven by increasing atmospheric CO2 . Many sites where currently both tree-dominated and grass-dominated biomes are possible become deterministically tree-dominated. Regions with multiple stable biome states are widespread and require consideration when attempting to predict future vegetation changes. Testing for behaviour characteristic of systems with multiple stable equilibria, such as hysteresis and dependence on historical conditions, and the resulting uncertainty in simulated vegetation, will lead to improved projections of global change impacts.
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Affiliation(s)
- Glenn R Moncrieff
- Institute for Physical Geography, Goethe University Frankfurt am Main, Altenhöferallee 1, 60438, Frankfurt am Main, Germany
| | - Simon Scheiter
- Biodiversity and Climate Research Centre, Senckenberg Research Institute and Natural History Museum, Senckenberganlage 25, 60325, Frankfurt am Main, Germany
| | - William J Bond
- Department of Biological Sciences, University of Cape Town, Private Bag, Rondebosch, 7701, Cape Town, South Africa
| | - Steven I Higgins
- Department of Botany, University of Otago, PO Box 56, Dunedin, 9054, New Zealand
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10
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Rao Z, Chen F, Zhang X, Xu Y, Xue Q, Zhang P. Spatial and temporal variations of C3/C4 relative abundance in global terrestrial ecosystem since the Last Glacial and its possible driving mechanisms. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/s11434-012-5233-9] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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11
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Abstract
During the Last Glacial Maximum (LGM; 18,000-20,000 yr ago) and previous glacial periods, atmospheric [CO(2)] dropped to 180-190 ppm, which is among the lowest concentrations that occurred during the evolution of land plants. Modern atmospheric CO(2) concentrations ([CO(2)]) are more than twice those of the LGM and 45% higher than pre-industrial concentrations. Since CO(2) is the carbon source for photosynthesis, lower carbon availability during glacial periods likely had a major impact on plant productivity and evolution. From the studies highlighted here, it is clear that the influence of low [CO(2)] transcends several scales, ranging from physiological effects on individual plants to changes in ecosystem functioning, and may have even influenced the development of early human cultures (via the timing of agriculture). Through low-[CO(2)] studies, we have determined a baseline for plant response to minimal [CO(2)] that occurred during the evolution of land plants. Moreover, an increased understanding of plant responses to low [CO(2)] contributes to our knowledge of how natural global change factors in the past may continue to influence plant responses to future anthropogenic changes. Future work, however, should focus more on the evolutionary responses of plants to changing [CO(2)] in order to account for the potentially large effects of genetic change.
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Affiliation(s)
- Laci M Gerhart
- Department of Ecology & Evolutionary Biology, University of Kansas, Lawrence, KS 66045, USA
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12
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Rector AL, Verrelli BC. Glacial cycling, large mammal community composition, and trophic adaptations in the Western Cape, South Africa. J Hum Evol 2009; 58:90-102. [PMID: 19914679 DOI: 10.1016/j.jhevol.2009.09.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2009] [Revised: 08/29/2009] [Accepted: 09/22/2009] [Indexed: 10/20/2022]
Abstract
Some of the earliest evidence for modern human behavior has been recovered from the Western Cape Province, South Africa. Archaeological and paleontological sites in the Western Cape are typically described as "glacial" or "interglacial" in aspect based on the numbers of grazers found in the faunal assemblage, as glacial periods are often thought to have been characterized by spreading C(4) grasslands that replaced endemic C(3) shrubland vegetation found in the Western Cape today. Here, we test the hypothesis that glacial and interglacial time periods were associated with a predictable change in large mammal trophic adaptations by analyzing the proportions of grazing larger mammals from 118 levels of 15 Western Cape fossil assemblages sampling marine isotope stage (MIS) 6 to the present time to determine whether there is a change in composition in these communities that might reflect a shift in ecology and habitat. Our results indicate that trophic proportions did not significantly change over time in the Western Cape as a whole, and thus the hypothesis for habitat changes affecting the subsistence ecology of modern humans during the development of modern behavior is not supported. However, our results show that the southwestern subregion of the Western Cape was characterized by the presence of more grazing species through time than the western subregion. Thus, if ecological and population isolation during glacial periods were integral to catalyzing the development of modern behaviors in the Western Cape region of South Africa, then a complex model including the development of possible mosaic habitats is needed.
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Affiliation(s)
- Amy L Rector
- Institute of Human Origins and School of Human Evolution and Social Change, Arizona State University, Tempe, AZ, USA.
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13
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Rao Z, Jia G, Zhu Z, Wu Y, Zhang J. Comparison of the carbon isotope composition of total organic carbon and long-chain n-alkanes from surface soils in eastern China and their significance. Sci Bull (Beijing) 2008. [DOI: 10.1007/s11434-008-0296-3] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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14
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Wu H, Guiot J, Brewer S, Guo Z, Peng C. Dominant factors controlling glacial and interglacial variations in the treeline elevation in tropical Africa. Proc Natl Acad Sci U S A 2007; 104:9720-4. [PMID: 17535920 PMCID: PMC1887610 DOI: 10.1073/pnas.0610109104] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The knowledge of tropical palaeoclimates is crucial for understanding global climate change, because it is a test bench for general circulation models that are ultimately used to predict future global warming. A longstanding issue concerning the last glacial maximum in the tropics is the discrepancy between the decrease in sea-surface temperatures reconstructed from marine proxies and the high-elevation decrease in land temperatures estimated from indicators of treeline elevation. In this study, an improved inverse vegetation modeling approach is used to quantitatively reconstruct palaeoclimate and to estimate the effects of different factors (temperature, precipitation, and atmospheric CO(2) concentration) on changes in treeline elevation based on a set of pollen data covering an altitudinal range from 100 to 3,140 m above sea level in Africa. We show that lowering of the African treeline during the last glacial maximum was primarily triggered by regional drying, especially at upper elevations, and was amplified by decreases in atmospheric CO(2) concentration and perhaps temperature. This contrasts with scenarios for the Holocene and future climates, in which the increase in treeline elevation will be dominated by temperature. Our results suggest that previous temperature changes inferred from tropical treeline shifts may have been overestimated for low-CO(2) glacial periods, because the limiting factors that control changes in treeline elevation differ between glacial and interglacial periods.
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Affiliation(s)
- Haibin Wu
- *State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China
- Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, Unité Mixte de Recherche 6635, Centre National de la Recherche Scientifique/Université Paul Cézanne, BP 80, 13545 Aix-en-Provence Cedex 4, France
- Institut des Sciences de l'Environnement, Département des Sciences Biologiques, Université du Québec à Montreal, Montréal, QC, Canada H3C 3P8
- To whom correspondence may be addressed. E-mail: or
| | - Joël Guiot
- Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, Unité Mixte de Recherche 6635, Centre National de la Recherche Scientifique/Université Paul Cézanne, BP 80, 13545 Aix-en-Provence Cedex 4, France
| | - Simon Brewer
- Centre Européen de Recherche et d'Enseignement des Géosciences de l'Environnement, Unité Mixte de Recherche 6635, Centre National de la Recherche Scientifique/Université Paul Cézanne, BP 80, 13545 Aix-en-Provence Cedex 4, France
| | - Zhengtang Guo
- *State Key Laboratory of Loess and Quaternary Geology, Institute of Earth Environment, Chinese Academy of Sciences, Xi'an 710075, China
- Institute of Geology and Geophysics, Chinese Academy of Sciences, P.O. Box 9825, Beijing 100029, China; and
| | - Changhui Peng
- Institut des Sciences de l'Environnement, Département des Sciences Biologiques, Université du Québec à Montreal, Montréal, QC, Canada H3C 3P8
- To whom correspondence may be addressed. E-mail: or
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15
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Rathgeber C, Nicault A, Kaplan JO, Guiot J. Using a biogeochemistry model in simulating forests productivity responses to climatic change and [CO2] increase: example of Pinus halepensis in Provence (south-east France). Ecol Modell 2003. [DOI: 10.1016/s0304-3800(03)00161-3] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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16
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Kaplan JO. Climate change and Arctic ecosystems: 2. Modeling, paleodata-model comparisons, and future projections. ACTA ACUST UNITED AC 2003. [DOI: 10.1029/2002jd002559] [Citation(s) in RCA: 378] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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17
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Roelandt C. Coupled simulation of potential natural vegetation, terrestrial carbon balance and physical land-surface properties with the ALBIOC model. Ecol Modell 2001. [DOI: 10.1016/s0304-3800(01)00331-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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18
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Boom A, Mora G, Cleef AM, Hooghiemstra H. High altitude C(4) grasslands in the northern Andes: relicts from glacial conditions? REVIEW OF PALAEOBOTANY AND PALYNOLOGY 2001; 115:147-160. [PMID: 11440767 DOI: 10.1016/s0034-6667(01)00056-2] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The altitudinal vegetation distribution in the northern Andes during glacial time differed from the present-day conditions as a result of temperature and precipitation change. New evidence indicate that as a response to a reduced atmospheric partial CO(2) pressure (pCO(2)), the competitive balance between C(3) and C(4) plants have changed. Effects may have remained virtually undetected in pollen records, but can be observed using a stable carbon isotope analysis. Vegetation dominated by C(4) taxa, belonging to the families Cyperaceae (e.g. Bulbostylis and Cyperus) and Poaceae (e.g. Muhlenbergia, Paspalum and Sporobolus), may have been able to replace for a significant part the modern type C(3) taxa (e.g. species belonging to Carex, Rhynchospora, Aciachne, Agrostis, Calamagrostis, and Chusquea). Impact of reduced glacial atmospheric pCO(2) levels and lower glacial temperatures on the composition and the elevational distribution of the vegetation types is discussed. The present high Andean vegetation communities may differ from the glacial equivalents (non-modern analogue situation). We identified dry Sporobolus lasiophyllus tussock grassland and Arcytophyllum nitidum dwarfshrub paramo as the possible relict communities from glacial time. The effect on previous estimates of paleo-temperatures is estimated to be small.
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Affiliation(s)
- A Boom
- Hugo de Vries-Laboratory, Department of Palynology and Paleo/Actuo-Ecology, Center for Geo-ecological Research (ICG), University of Amsterdam, Kruislaan 318, 1098 SM, Amsterdam, The Netherlands
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19
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Hostetler SW, Clark PU. Tropical climate at the last glacial maximum inferred from glacier mass-balance modeling. Science 2000; 290:1747-50. [PMID: 11099409 DOI: 10.1126/science.290.5497.1747] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Model-derived equilibrium line altitudes (ELAs) of former tropical glaciers support arguments, based on other paleoclimate data, for both the magnitude and spatial pattern of terrestrial cooling in the tropics at the last glacial maximum (LGM). Relative to the present, LGM ELAs were maintained by air temperatures that were 3.5 degrees to 6.6 degrees C lower and precipitation that ranged from 63% wetter in Hawaii to 25% drier on Mt. Kenya, Africa. Our results imply the need for a approximately 3 degrees C cooling of LGM sea surface temperatures in the western Pacific warm pool. Sensitivity tests suggest that LGM ELAs could have persisted until 16,000 years before the present in the Peruvian Andes and on Papua, New Guinea.
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Affiliation(s)
- S W Hostetler
- U.S. Geological Survey, Department of Geosciences, Oregon State University, Corvallis, OR 97331, USA.
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20
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From static biogeographical model to dynamic global vegetation model: a global perspective on modelling vegetation dynamics. Ecol Modell 2000. [DOI: 10.1016/s0304-3800(00)00348-3] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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21
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Rathgeber C, Guiot J, Edouard JL. [Utilization of a biogeochemical model in dendroecology. Application to the Cembro pine]. COMPTES RENDUS DE L'ACADEMIE DES SCIENCES. SERIE III, SCIENCES DE LA VIE 2000; 323:489-97. [PMID: 10879297 DOI: 10.1016/s0764-4469(00)00154-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Dendroecology, which is based on annual growth variable measurements, is in possession of data particularly well adapted to analyse the impact of global change on vegetation production. But the classical statistical methods of quantification of tree ring-climate relationship cannot take into account the effect of CO2 increase. Therefore, a biogeochemistry model (BIOME3) has been adapted to these data and then validated on Pinus cembra. The results indicate that the production is reduced by 14% if only the climatic changes are taken into account. If both climatic changes and CO2 increase are taken into account the production is increased by 62%. The direct fertilisation effect of CO2 increase will have more influence on the productivity than the indirect climatic effect.
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Affiliation(s)
- C Rathgeber
- Institut méditerranéen d'écologie et de paléoécologie (Imep), CNRS Upres A 6116, Faculté des sciences et techniques de Saint-Jérôme, Marseille, France.
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Inverse vegetation modeling by Monte Carlo sampling to reconstruct palaeoclimates under changed precipitation seasonality and CO2 conditions: application to glacial climate in Mediterranean region. Ecol Modell 2000. [DOI: 10.1016/s0304-3800(99)00219-7] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Bush ABG, Philander SGH. The climate of the Last Glacial Maximum: Results from a coupled atmosphere-ocean general circulation model. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999jd900447] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mahowald N, Kohfeld K, Hansson M, Balkanski Y, Harrison SP, Prentice IC, Schulz M, Rodhe H. Dust sources and deposition during the last glacial maximum and current climate: A comparison of model results with paleodata from ice cores and marine sediments. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999jd900084] [Citation(s) in RCA: 529] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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Malaizé B, Paillard D, Jouzel J, Raynaud D. The Dole effect over the last two glacial-interglacial cycles. ACTA ACUST UNITED AC 1999. [DOI: 10.1029/1999jd900116] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Street-Perrott FA, Huang Y, Perrott RA, Eglinton G, Barker P, Khelifa LB, Harkness DD, Olago DO. Impact of lower atmospheric carbon dioxide on tropical mountain ecosystems. Science 1997; 278:1422-6. [PMID: 9367947 DOI: 10.1126/science.278.5342.1422] [Citation(s) in RCA: 282] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Carbon-isotope values of bulk organic matter from high-altitude lakes on Mount Kenya and Mount Elgon, East Africa, were 10 to 14 per mil higher during glacial times than they are today. Compound-specific isotope analyses of leaf waxes and algal biomarkers show that organisms possessing CO2-concentrating mechanisms, including C4 grasses and freshwater algae, were primarily responsible for this large increase. Carbon limitation due to lower ambient CO2 partial pressures had a significant impact on the distribution of forest on the tropical mountains, in addition to climate. Hence, tree line elevation should not be used to infer palaeotemperatures.
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Affiliation(s)
- FA Street-Perrott
- F. A. Street-Perrott and R. A. Perrott are in the Tropical Palaeoenvironments Research Group, Department of Geography, University of Wales Swansea, Swansea SA2 8PP, UK. Y. Huang and G. Eglinton are at the Biogeochemistry Research C
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