Hostname: page-component-cd9895bd7-dk4vv Total loading time: 0 Render date: 2024-12-27T11:18:47.944Z Has data issue: false hasContentIssue false
  • English
  • Français

Holocene Vegetation Change at Treeline North of Yellowknife, Northwest Territories, Canada

Published online by Cambridge University Press:  20 January 2017

K. A. Moser  and
G. M. MacDonald
K. A. Moser
Affiliation:
Department of Geography, McMaster University, Hamilton, Ontario, Canada L8S 4K1
G. M. MacDonald
Affiliation:
Department of Geography, McMaster University, Hamilton, Ontario, Canada L8S 4K1
Get access Rights & Permissions [Opens in a new window]

Abstract

Two radiocarbon-dated cores from small lakes located approximately 25 km north of the mapped boundary between forest-tundra and tundra provide records of postglacial vegetation change at the treeline near Yellowknife, NWT, Canada. Basal radiocarbon dates of 6180 and 7470 yr B.P. were obtained from the cores. The fossil pollen evidence suggests that the initial vegetation was Betula tundra with a peatland component. Alnus became an important constituent of the pollen assemblages between 6900 and 5500 yr B.P. Both lakes record sharp increases in Picea cf. mariana pollen at approximately 5000 yr B.P., suggesting the establishment of forest-tundra. By 3500 yr B.P. Picea mariana forest-tundra had withdrawn. The proportion of organic to inorganic sediment in the cores was at a maximum between 5000 and 3500 yr B.P. Tundra has dominated the region since 3500 yr B.P. In northwestern Canada, the maximum northward advance of treeline occurred between 9000 and 5000 yr B.P. The asynchrony in treeline advance in central and northwestern Canada may reflect that glacial ice persisted in the interior NWT longer than previously believed. Alternatively, the asynchronous history of the treeline may be a result of the geometric properties of the long-wave westerly disturbance that is manifest in the median summer position of the arctic front and ultimately controls the geographic location of the treeline.

Type
Articles
Information
Quaternary Research , Volume 34 , Issue 2 , September 1990 , pp. 227 - 239
Copyright
University of Washington

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Bryson, R.A., (1966). Air masses, streamlines, and the Boreal forest Geographical Bulletin 8 228–269 Google Scholar
Bryson, R.A. Wendland, W.M., (1967). Tentative climatic patterns for some late-glacial and post-glacial episodes in central North America Mayer-Oakes, W.J. Life, Land and Water Univ. of Manitoba Press Winnipeg 271–298 Google Scholar
Cwynar, L.C. Burden, E. McAndrews, J.H., (1979). An inexpensive sieving method for concentrating pollen and spores from fine-grained sediments Canadian Journal of Earth Sciences 16 1115–1120 Google Scholar
Davis, M.B. Ford, M.S., (1982). Sediment focusing in Mirror Lake, New Hampshire Limnology and Oceanography 27 137–150 CrossRefGoogle Scholar
Dean, W.E., (1974). Determination of carbonate and organic matter in calcareous sediments and sedimentary rocks by loss on ignition: Comparison with other methods Journal of Sedimentary Petrology 44 242–248 Google Scholar
Dyke, A.S. Prest, V.K., (1987). Late Wisconsinan and Holocene history of the Laurentide Ice Sheet Geographie Physique et Quaternaire 41 237–264 and maps Google Scholar
Elliott-Fisk, D.L., (1983). The stability of the northern Canadian tree limit Annals of the American Association of Geographers 73 560–577 Google Scholar
Engstrom, D.R. Hansen, B.C.S., (1985). Post-glacial vegetational change and soil development in southeastern Labrador as inferred from pollen and chemical stratigraphy Canadian Journal of Botany 63 543–561 Google Scholar
Environment Canada Canadian Climate Normals, Temperature and Precipitation: The North (1982). Atmospheric Environmental Service Toronto Google Scholar
Faegri, K. Iversen, J., (1975). 3rd ed. Textbook of Pollen Analysis Munksgaard Copenhagen Google Scholar
Grime, J.P. Hodgson, Hunt, R., (1988). Comparative Plant Ecology Hyman London CrossRefGoogle Scholar
Hansen, B.C.S. Engstrom, D.R., (1985). A Comparison of numerical and qualitative methods of separating pollen of black and white spruce Canadian Journal of Botany 63 2159–2163 Google Scholar
Hare, F.K., (1973). On the climatology of post-Wisconsin events in Canada Arctic and Alpine Research 5 169–170 CrossRefGoogle Scholar
Hare, F.K., (1976). Late Pleistocene and Holocene climates: Some persistent problems Quaternary Research 6 507–517 Google Scholar
Hare, F.K. Ritchie, J.C., (1972). The boreal bioclimates Geographical Reviews 62 334–365 CrossRefGoogle Scholar
Henderson, J.B., (1985). Geology of the Yellowknife-Hearne Lake area, District of Mackenzie: A segment across an Archaen basin Geological Survey of Canada Memoir 414.y Google Scholar
Kay, P.A., (1979). Multivariate statistical estimates of Holocene vegetation and climate change, forest-tundra transition zone, NWT, Canada Quaternary Research 11 125–140 Google Scholar
Kutzbach, J.E. Guetter, P.J., (1986). The influence of changing orbital parameters and surface boundary conditions on climate simulations for the past 18 000 years American Meterological Society 42 1726–1759 Google Scholar
MacDonald, G.M., (1987). Postglacial vegetation history of the Mackenzie River basin Quaternary Research 28 245–262 Google Scholar
MacDonald, G.M., (1988). Methods in Quaternary ecology. 2. Palynology Geoscience Canada 15 29–42 Google Scholar
MacDonald, G.M. Ritchie, J.C., (1986). Modern pollen spectra from the western interior of Canada and the interpretation of late Quaternary vegetation development New Phytologist 103 245–268 Google Scholar
Namais, J., (1970). Climatic anomaly over the United States during the 1960's Science 170 741–743 Google Scholar
National Atlas of Canada (1972). MacMillan Company Toronto Google Scholar
Nichols, H., (1967). Diagrams from sub-Arctic central Canada Science 155 1665–1668 CrossRefGoogle ScholarPubMed
Nichols, H., (1975). Palynological and Paleoclimatic Study of the Late Quaternary Displacement of the Boreal Forest-Tundra Ecotone in Keewatin and Mackenzie, NWT, Canada University of Colorado, Institute of Arctic and Alpine Research Occasional paper 15 Google Scholar
Porsild, A.E. Cody, W.J., (1980). Vascular Plants of the Continental Northwest Territories National Museum of Canada Ottawa CrossRefGoogle Scholar
Richard, P., (1970). Atlas pollinique des arbres et de quelques arbustes indigenes du Quebec, III Naturaliste Canadien 97 97–161 Google Scholar
Ritchie, J.C., (1974). Modern pollen assemblages near the arctic treeline, Mackenzie Delta region, Northwest Territories Canadian Journal of Botany 52 381–396 CrossRefGoogle Scholar
Ritchie, J.C., (1984). Past and Present Vegetation of the Far Northwest of Canada Univ. of Toronto Press Toronto CrossRefGoogle Scholar
Ritchie, J.C. Cwynar, L.C. Spear, R.W., (1983). Evidence from north-west Canada for an early Holocene Milankovitch thermal maximum Nature 305 126–127 Google Scholar
Ritchie, J.C. Hare, F.K., (1971). Late-Quaternary vegetation and climate near arctic tree line of northwestern North America Quaternary Research 1 331–341 Google Scholar
Ritchie, J.C. MacDonald, G.M., (1986). The patterns of post-glacial spread of white spruce Journal of Biogeography 13 527–540 CrossRefGoogle Scholar
Sorenson, C.J., (1977). Reconstructed Holocene bioclimates Annals of the American Association of Geographers 67 214–222 Google Scholar
Spear, R.W., (1983). Paleoecological approaches to a study of treeline fluctuation in the Mackenzie Delta region, Northwest Territories: Preliminary results Nordicana 47 61–72 Google Scholar
Wetzel, R.G., (1983). Limnology Sauders College Publishing Philadelphia Google Scholar
Wright, H.E. Jr. Mann, D.H. Glaser, P.H., (1984). Piston cores for peat and lake sediments Ecology 65 657–659 CrossRefGoogle Scholar