Abstract
The mid-elevation settings of the Andes are important biodiversity hotspots, yet little is known of their long-term ecology or environmental change. Here, we assess 30,000 years of landscape and vegetation dynamics on an alluvial terrace located in a mid-elevation valley of the Ecuadorian Andes (Campo Libre). We used loss-on-ignition and particle size analysis to reconstruct past river dynamics, charcoal analysis to reconstruct past fire regimes, and phytolith analysis to reconstruct vegetation change through time. Our results show that Campo Libre was a part of the active floodplain system of the Quijos River until 18,000 cal yr BP. The biggest vegetation change in vegetation at Campo Libre occurred ca. 13,000 cal yr BP, when the site warmed and dried, transforming the swampy alluvial terrace into a palm forest. As Holocene precipitation increased, the site transformed back into a swamp around 7500 cal yr BP, and it remained that way until maize agriculture began around 4600 cal yr BP. Local and regional fires were absent from the system until regional fires were detected ca. 3300 cal yr BP. By ca. 2700 cal yr BP, maize cultivation became frequent and regular. Climate, tectonic activity, and the human history have shaped the modern vegetation around Campo Libre, although during different periods of the Holocene. Our results demonstrate the ability of phytoliths to reconstruct vegetation change through time, and show that the mid-elevation Andean valley systems were highly dynamic over the last 30,000 years.
Original language | English |
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Article number | 106866 |
Pages (from-to) | 1-12 |
Number of pages | 12 |
Journal | Quaternary Science Reviews |
Volume | 258 |
Early online date | 19 Mar 2021 |
DOIs | |
Publication status | Published - 15 Apr 2021 |
Bibliographical note
Funding Information:We would like to thank Joe Williams and Macarena Cardenas for their assistance with fieldwork, Isa Mulder for assisting with the charcoal analysis, and Annemarie Phillip for the processing of phytolith and pollen samples. This work is a part of a NASA Interdisciplinary Research in Earth Science NNX14AD31G to C.N.H.M., and was also supported by funds from the Open University to W.D.G. We would also like to thank the Royal Botanic Garden Edinburgh, Santander, and the British Ecological Society (small ecological project grant #1052/1947 ) for supporting the project. This work was also supported by the MSc Biology and MSc Earth Sciences programs in the Institute for Biodiversity and Ecosystem Dynamics at the University of Amsterdam. B.C.L. and the 14 C dates obtained from Uppsala were funded by Swedish Research Council (Vetenskapsrådet) grant number 637-2014-499 .
Publisher Copyright:
© 2021 The Authors
Copyright:
Copyright 2021 Elsevier B.V., All rights reserved.
Keywords
- Charcoal
- Eastern Andes
- Fire
- Holocene
- Palms
- Phytoliths
- Pleistocene
- River dynamics