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Schiferl J, Kingston M, Åkesson CM, Valencia BG, Rozas-Davila A, McGee D, Woods A, Chen CY, Hatfield RG, Rodbell DT, Abbott MB, Bush MB. A neotropical perspective on the uniqueness of the Holocene among interglacials. Nat Commun 2023; 14:7404. [PMID: 37973878 PMCID: PMC10654573 DOI: 10.1038/s41467-023-43231-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2023] [Accepted: 11/03/2023] [Indexed: 11/19/2023] Open
Abstract
Understanding how tropical systems have responded to large-scale climate change, such as glacial-interglacial oscillations, and how human impacts have altered those responses is key to current and future ecology. A sedimentary record recovered from Lake Junín, in the Peruvian Andes (4085 m elevation) spans the last 670,000 years and represents the longest continuous and empirically-dated record of tropical vegetation change to date. Spanning seven glacial-interglacial oscillations, fossil pollen and charcoal recovered from the core showed the general dominance of grasslands, although during the warmest times some Andean forest trees grew above their modern limits near the lake. Fire was very rare until the last 12,000 years, when humans were in the landscape. Here we show that, due to human activity, our present interglacial, the Holocene, has a distinctive vegetation composition and ecological trajectory compared with six previous interglacials. Our data reinforce the view that modern vegetation assemblages of high Andean grasslands and the presence of a defined tree line are aspects of a human-modified landscape.
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Affiliation(s)
- J Schiferl
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL, 32901, USA
| | - M Kingston
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL, 32901, USA
| | - C M Åkesson
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL, 32901, USA
| | - B G Valencia
- Facultad de Ciencias de La Tierra y Agua, Universidad Regional Amazónica Ikiam, Tena, Ecuador
| | - A Rozas-Davila
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL, 32901, USA
| | - D McGee
- Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - A Woods
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA, USA
| | - C Y Chen
- Chemical and Isotopic Signatures Group, Nuclear and Chemical Sciences Division, Lawrence Livermore National Laboratory, Livermore, CA, 94550, USA
| | - R G Hatfield
- Department of Geological Sciences, University of Florida, Gainesville, FL, 32611, USA
| | - D T Rodbell
- Geoscience Department, Union College, Schenectady, NY, 12308, USA
| | - M B Abbott
- Department of Geology and Environmental Science, University of Pittsburgh, Pittsburgh, PA, USA
| | - M B Bush
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL, 32901, USA.
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Bush MB, Rozas-Davila A, Raczka M, Nascimento M, Valencia B, Sales RK, McMichael CNH, Gosling WD. A palaeoecological perspective on the transformation of the tropical Andes by early human activity. Philos Trans R Soc Lond B Biol Sci 2022; 377:20200497. [PMID: 35249394 PMCID: PMC8899620 DOI: 10.1098/rstb.2020.0497] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Palaeoecological records suggest that humans have been in the Andes since at least 14 000 years ago. Early human impacts on Andean ecosystems included an increase in fire activity and the extinction of the Pleistocene megafauna. These changes in Andean ecosystems coincided with rapid climate change as species were migrating upslope in response to deglacial warming. Microrefugia probably played a vital role in the speed and genetic composition of that migration. The period from ca 14 500 to 12 500 years ago was when novel combinations of plant species appeared to form no-analogue assemblages in the Andes. By 12 000 years ago most areas in what are today the Andean grasslands were being burned and modified by human activity. As the vegetation of these highland settings has been modified by human activity for the entirety of the Holocene, they should be regarded as long-term manufactutred landscapes. The sharp tree lines separating Andean forests from grasslands that we see today were probably also created by repeated burning and owe their position more to human-induced fire than climatic constraints. In areas that were readly penetrated by humans on the forested slopes of the Andes, substantial modification and settlement had occurred by the mid-Holocene. In hard-to-reach areas, however, the amount of human modification may always have been minimal, and these slopes can be considered as being close to natural in their vegetation. This article is part of the theme issue 'Tropical forests in the deep human past'.
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Affiliation(s)
- M B Bush
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL 32901, USA
| | - A Rozas-Davila
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL 32901, USA
| | - M Raczka
- Department of Geography and Environmental Science, University of Reading, Whiteknights, Reading, Berkshire RG6 6AH, UK
| | - M Nascimento
- Department of Ecosystem and Landscape Dynamics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 904 Science Park, 1098 XH, Amsterdam, Netherlands
| | - B Valencia
- Facultad de Ciencias de la Tierra y Agua, Ciencias de la Tierra y Clima, Universidad Regional Amazónica Ikiam, Tena, Ecuador
| | - R K Sales
- Institute for Global Ecology, Florida Institute of Technology, Melbourne, FL 32901, USA
| | - C N H McMichael
- Department of Ecosystem and Landscape Dynamics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 904 Science Park, 1098 XH, Amsterdam, Netherlands
| | - W D Gosling
- Department of Ecosystem and Landscape Dynamics, Institute for Biodiversity and Ecosystem Dynamics, University of Amsterdam, 904 Science Park, 1098 XH, Amsterdam, Netherlands
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