Holocene fossil beetles from a treeline peatland in subarctic Quebec
We analyzed the fossil insect fauna of a palsa peatland located 10 km south and east of the treeline in subarctic Quebec (57°45′N, 76°15′W) to detect any changes in the species composition during the Holocene epoch and to infer past environmental conditions in the study area. A minimum of 802 beetle...
| Published in: | Canadian Journal of Zoology |
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| Main Authors: | , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
Canadian Science Publishing
1997
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| Subjects: | |
| Online Access: | http://dx.doi.org/10.1139/z97-029 http://www.nrcresearchpress.com/doi/pdf/10.1139/z97-029 |
| Summary: | We analyzed the fossil insect fauna of a palsa peatland located 10 km south and east of the treeline in subarctic Quebec (57°45′N, 76°15′W) to detect any changes in the species composition during the Holocene epoch and to infer past environmental conditions in the study area. A minimum of 802 beetle individuals were recovered from a 2-m peat section, representing 51 taxa (18 identified to the species level) and 8 families. Trechus crassiscapus, Eucnecosum brunnescens, and Olophrum rotundicolle were the most common species found in the peat. The insect assemblage was quite stable through the study interval (5850–1950 BP). The formation of the palsa (where the peat section was excavated) occurred probably after 1950 BP, raising the soil surface above water level and preventing additional peat accumulation. The proportion of boreal forest species in the faunal assemblage is high (88%). The only arctic (tundra) species found were Amara alpina and Pterostichus arcticola. Many species were out of their modern distribution range, but since collection localities are scarce in subarctic Quebec, the modern range of these species may extend to the study site. A mutual climatic range analysis, employing beetles identified to the species level, showed that the mean July temperature of the study area between 5850 and 1950 BP was possibly 2.8–5.5 °C higher than during the 20th century. This assertion is supported by other paleoecological data (pollen and charcoal remains) suggesting a cooling trend in the study area after 2000 BP. However, since the last 2000 years are missing from the sampled peat section, it was not possible to quantify the impact of the cooling trend on the beetle fauna. |
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