Environmental change in the Colombian subandean forest belt from 8 pollen records: the last 50 kyr |
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Authors: | Michael Wille Henry Hooghiemstra Hermann Behling Klaas van der Borg Alvora Jose Negret |
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Institution: | (1) University of Amsterdam, Institute for Biodiversity and Ecosystem Dynamics (IBED, Dept. of Palynology and Paleo/Actuoecology (participating in: Centre for Geo-ecological Research (ICG)), Kruislaan 318, 1098 SM Amsterdam, The Netherlands. E-mail: wille@science.uva.nl, hooghiemstra@science.uva.nl, NL;(2) Centre for Tropical Marine Ecology, Fahrenheitstrasse 1, 28359 Bremen, Germany. E-mail: hbehling@zmt.uni-bremen.de, DE;(3) Van der Graaff Laboratory, Utrecht University, Princetonplein 5, 3508 TA Utrecht, The Netherlands, NL;(4) Museo De Historia Natural, Universidad del Cauca, Carrera 2a 1A-25, Popayán, Colombia, CO |
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Abstract: | We present a reconstruction of forest history and climatic change based on 11 pollen records from eight sites, all located
in the lower montane forest belt of the northern Andes in Colombia. We compared records from the Popayán area in southern
Colobia, Timbio (1750 m), Genagra (1750 m) and Pitalito (1300 m) and the new Piagua (1700 m) record with the records from
Lusitania (1500 m), Libano (1820 m), Pedro Palo (2000 m) and Ubaqué (2000 m) from Central Colombia. The changes of the altitudinal
position of the lower/upper montane (= subandean/Andean, S/At) forest belt transition were used to estimate temperature change
for the last 50 kyr. We infer a Last Glacial Maximum (LGM) temperature drop of 6°–7°C at 1700 m, and a steeper LGM lapse rate
of 0.76°C/100 m compared to today (ca. 0.6°C/100 m). Around 50 uncal. kyr B.P. the temperature at 1700 m was ca. 3°C lower
than today. Until 20 uncal. kyr B.P. the temperature oscillated and gradually decreased. During the LGM, temperature was down
to ca. 6°–7°C lower than today. After the LGM, temperature increased and ca. 14 uncal. kyr B.P. it was 2°–3°C lower than today
(S/At at ca. 1800 m, 500 m below present elevation; Susacá interstadial). An unquantified cooling (Ciega stadial) followed.
During ca. 12.3–11.7 uncal. kyr B.P. the S/At shifted upslope to 2100 m indicating a temperature of 1°–2°C cooler than today
(Guantiva interstadial). From 11.7–10.9 uncal. kyr B.P. the S/At was at 1800 m indicating that the temperature was ca. 3°C
lower than today and wet conditions prevailed (partly coinciding with the El Abra stadial). The period 10.9–9 uncal. kyr B.P.
was also cool, but drier. During 9–7.5 uncal. kyr B.P. temperature was ca. 1°C warmer relative to today (mid Holocene hypsithermal).
During the last 5 kyr the presence of cultivated plants demonstates human colonization of the lower montane zone in Colombia.
Received June 14, 2000 / Accepted December 19, 2000 |
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Keywords: | : Pollen records – Climate – Lapse rate – Late Quaternary – Colombia |
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