Predicting Pleistocene climate from vegetation in North America
Climates at the Last Glacial Maximum have been inferred from fossil pollen assemblages, but these inferred climates are colder for eastern North America than those produced by climate simulations. It has been suggested that low CO 2 levels could account for this discrepancy. In this study biogeograp...
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ftdoajarticles:oai:doaj.org/article:9aed0619d80043418149a218f1dcd8f3 2023-05-15T18:40:45+02:00 Predicting Pleistocene climate from vegetation in North America C. Loehle 2007-01-01T00:00:00Z https://doaj.org/article/9aed0619d80043418149a218f1dcd8f3 EN eng Copernicus Publications http://www.clim-past.net/3/109/2007/cp-3-109-2007.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 https://doaj.org/article/9aed0619d80043418149a218f1dcd8f3 Climate of the Past, Vol 3, Iss 1, Pp 109-118 (2007) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2007 ftdoajarticles 2022-12-31T15:02:00Z Climates at the Last Glacial Maximum have been inferred from fossil pollen assemblages, but these inferred climates are colder for eastern North America than those produced by climate simulations. It has been suggested that low CO 2 levels could account for this discrepancy. In this study biogeographic evidence is used to test the CO 2 effect model. The recolonization of glaciated zones in eastern North America following the last ice age produced distinct biogeographic patterns. It has been assumed that a wide zone south of the ice was tundra or boreal parkland (Boreal-Parkland Zone or BPZ), which would have been recolonized from southern refugia as the ice melted, but the patterns in this zone differ from those in the glaciated zone, which creates a major biogeographic anomaly. In the glacial zone, there are few endemics but in the BPZ there are many across multiple taxa. In the glacial zone, there are the expected gradients of genetic diversity with distance from the ice-free zone, but no evidence of this is found in the BPZ. Many races and related species exist in the BPZ which would have merged or hybridized if confined to the same refugia. Evidence for distinct southern refugia for most temperate species is lacking. Extinctions of temperate flora were rare. The interpretation of spruce as a boreal climate indicator may be mistaken over much of the region if the spruce was actually an extinct temperate species. All of these anomalies call into question the concept that climates in the zone south of the ice were extremely cold or that temperate species had to migrate far to the south. An alternate hypothesis is that low CO 2 levels gave an advantage to pine and spruce, which are the dominant trees in the BPZ, and to herbaceous species over trees, which also fits the observed pattern. Thus climate reconstruction from pollen data is probably biased and needs to incorporate CO 2 effects. Most temperate species could have survived across their current ranges at lower abundance by retreating to moist microsites. ... Article in Journal/Newspaper Tundra Directory of Open Access Journals: DOAJ Articles Parkland ENVELOPE(-120.570,-120.570,55.917,55.917) |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 C. Loehle Predicting Pleistocene climate from vegetation in North America |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
Climates at the Last Glacial Maximum have been inferred from fossil pollen assemblages, but these inferred climates are colder for eastern North America than those produced by climate simulations. It has been suggested that low CO 2 levels could account for this discrepancy. In this study biogeographic evidence is used to test the CO 2 effect model. The recolonization of glaciated zones in eastern North America following the last ice age produced distinct biogeographic patterns. It has been assumed that a wide zone south of the ice was tundra or boreal parkland (Boreal-Parkland Zone or BPZ), which would have been recolonized from southern refugia as the ice melted, but the patterns in this zone differ from those in the glaciated zone, which creates a major biogeographic anomaly. In the glacial zone, there are few endemics but in the BPZ there are many across multiple taxa. In the glacial zone, there are the expected gradients of genetic diversity with distance from the ice-free zone, but no evidence of this is found in the BPZ. Many races and related species exist in the BPZ which would have merged or hybridized if confined to the same refugia. Evidence for distinct southern refugia for most temperate species is lacking. Extinctions of temperate flora were rare. The interpretation of spruce as a boreal climate indicator may be mistaken over much of the region if the spruce was actually an extinct temperate species. All of these anomalies call into question the concept that climates in the zone south of the ice were extremely cold or that temperate species had to migrate far to the south. An alternate hypothesis is that low CO 2 levels gave an advantage to pine and spruce, which are the dominant trees in the BPZ, and to herbaceous species over trees, which also fits the observed pattern. Thus climate reconstruction from pollen data is probably biased and needs to incorporate CO 2 effects. Most temperate species could have survived across their current ranges at lower abundance by retreating to moist microsites. ... |
format |
Article in Journal/Newspaper |
author |
C. Loehle |
author_facet |
C. Loehle |
author_sort |
C. Loehle |
title |
Predicting Pleistocene climate from vegetation in North America |
title_short |
Predicting Pleistocene climate from vegetation in North America |
title_full |
Predicting Pleistocene climate from vegetation in North America |
title_fullStr |
Predicting Pleistocene climate from vegetation in North America |
title_full_unstemmed |
Predicting Pleistocene climate from vegetation in North America |
title_sort |
predicting pleistocene climate from vegetation in north america |
publisher |
Copernicus Publications |
publishDate |
2007 |
url |
https://doaj.org/article/9aed0619d80043418149a218f1dcd8f3 |
long_lat |
ENVELOPE(-120.570,-120.570,55.917,55.917) |
geographic |
Parkland |
geographic_facet |
Parkland |
genre |
Tundra |
genre_facet |
Tundra |
op_source |
Climate of the Past, Vol 3, Iss 1, Pp 109-118 (2007) |
op_relation |
http://www.clim-past.net/3/109/2007/cp-3-109-2007.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 https://doaj.org/article/9aed0619d80043418149a218f1dcd8f3 |
_version_ |
1766230175258771456 |