Contemporary pollen spectra in the James Bay Lowland, Canada, and comparison with other forest-tundra assemblages
Contemporary pollen spectra obtained from twenty-eight sites in the southwestern James Bay area were examined as an aid to the interpretation of postglacial pollen diagrams. Picea is the dominant pollen type. Pinus banksiana and Betula pollen are prominent, with the shrub birches contributing most o...
| Published in: | Géographie physique et Quaternaire |
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| Main Author: | |
| Format: | Text |
| Language: | English |
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Les Presses de l’Université de Montréal
1980
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| Subjects: | |
| Online Access: | http://id.erudit.org/iderudit/1000415ar https://doi.org/10.7202/1000415ar |
| Summary: | Contemporary pollen spectra obtained from twenty-eight sites in the southwestern James Bay area were examined as an aid to the interpretation of postglacial pollen diagrams. Picea is the dominant pollen type. Pinus banksiana and Betula pollen are prominent, with the shrub birches contributing most of the latter. Other tree genera (Larix, Abies, Populus) extant in the area are underrepresented in the pollen assemblages. Among the shrub taxa present, pollen of two species of Alnus, A. crispa and A. rugosa, are regionally represented. Salix and Myrica pollen are notable locally at sites where these plants occur. Ericaceae values vary according to the type of sampling site. Cyperaceae and Sphagnum values fluctuate greatly depending on the proximity of these taxa to the sampling site. Pollen assemblages of the major taxa in six data sets extending from the forest-tundra of Saskatchewan to the eastern James Bay area in Québec were examined. Comparison yielded similar values of most genera. Local, regional and extra-regional influences, as well as over- and underrepresentation of individual taxa appear to apply uniformly over the entire area thereby providing pollen spectra representative of the forest-tundra of central Canada. Nous avons étudié les spectres polliniques contemporains de 28 sites au sud-ouest de la baie de James afin de faciliter l’interprétation des diagrammes polliniques postglaciaires. La présence de Picea est dominante alors que la proportion de Pinus banksiana et de Betula (surtout comme arbuste) est assez forte. Certaines espèces d’arbres (des genres Larix, Abies, Populus), qui croissent encore dans la région, sont sous-représentées dans les assemblages. Parmi les arbustes, le pollen de deux espèces d’Alnus, A. crispa et A. rugosa, est représenté à l’échelle régionale. Nous avons noté la présence locale de Salix et de Myrica là où poussent ces espèces. La fréquence des Éricacées varie selon le site de prélèvement. La représentation du pollen de Sphagnum et de Cypéracées varie beaucoup selon la ... |
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