Millennial-scale vegetation changes in the tropical Andes using ecological grouping and ordination methods
We compare eight pollen records reflecting climatic and environmental change from northern and southern sites in the tropical Andes. Our analysis focuses on the last 30 000 years, with particular emphasis on the Pleistocene to Holocene transition. We explore ecological grouping and downcore ordinati...
Main Authors: | , , , , , , , , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-03-01
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Series: | Climate of the Past |
Online Access: | http://www.clim-past.net/12/697/2016/cp-12-697-2016.pdf |
Summary: | We compare eight pollen records reflecting climatic and environmental change
from northern and southern sites in the tropical Andes. Our analysis focuses
on the last 30 000 years, with particular emphasis on the Pleistocene to
Holocene transition. We explore ecological grouping and downcore ordination
results as two approaches for extracting environmental variability from
pollen records. We also use the records of aquatic and shoreline vegetation
as markers for lake level fluctuations and moisture availability. Our
analysis focuses on the signature of millennial-scale climate variability in
the tropical Andes, in particular Heinrich stadials (HS) and Greenland
interstadials (GI).
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The pollen records show an overall warming trend during the
Pleistocene–Holocene transition, but the onset of post-glacial warming
differs in timing among records. We identify rapid responses of the tropical
vegetation to millennial-scale climate variability. The signatures of HS and
the Younger Dryas are generally recorded as downslope upper forest line
(UFL) migrations in our transect, and are likely linked to air temperature
cooling. The GI1 signal is overall comparable between northern and southern
records and indicates upslope UFL migrations and warming in the tropical
Andes. Our marker for lake level changes indicated a north-to-south
difference that could be related to moisture availability.
<br><br>
The air
temperature signature recorded by the Andean vegetation was consistent with
millennial-scale cryosphere and sea surface temperature changes but
suggests a potential difference between the magnitude of temperature change
in the ocean and the atmosphere. We also show that arboreal pollen percentage (AP %) and detrended correspondence analysis (DCA) scores are
two complementary approaches to extract environmental variability from
pollen records. |
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ISSN: | 1814-9324 1814-9332 |