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Paleoenvironmental Changes at the Northern Limit of the Subantarctic Nothofagus Forest, lat 37°S, Argentina

Published online by Cambridge University Press:  20 January 2017

Vera Markgraf
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Abstract

Paleoenvironmental changes dating back to before 10,000 yr B.P. at the northernmost occurrences of Nothofagus forests in Argentina at about latitude 37°S permit the reconstruction of past changes in the intensity of the winter rains, related to the southern westerlies that appear to determine the forest boundary. The paleoenvironmental interpretation is based on changes in the proportions of different Nothofagus species and changes in the ratio betwen forest and steppe taxa. The relatively most diverse and dense Nothofagus forest developed only during the last 4500 yr, prior to human impact during the last 300 yr. Before the middle Holocene, climatic conditions must have been different from the modern ones, with less overall precipitation judging from the overall lower amount of tree pollen and the reduction to primarily Nothfagus pumilio. An interval dated to older than 10,000 yr B.P. is characterized by co-occurrence of Prumnopitys andina, Nothofagus pumilio, and shrub-steppe taxa. Prumnopitys andina is known today only from scattered upper montane forest sites in Chile between 36° and 43°S lat and its ecological requirements are essentially unknown. The taxa combination, however, suggests that late-glacial climate must have been drier, and probably cooler than today. This implies that the winter rains and, consequently, the seasonal shift of the westerly circulation was reduced during the late Pleistocene and did not reach modern levels before 8500 yr B.P.

Type
Articles
Information
Quaternary Research , Volume 28 , Issue 1 , July 1987 , pp. 119 - 129
Copyright
University of Washington

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References

Auer, V. The Pleistocene of Fuego-Patagonia. Part II. The history of the flora and vegetation. Annales Academiae Scientiarum Fennicae 50 1958 1 239 Google Scholar
Bartley, D. D. Matthews, B. A palaeobotanical investigation of postglacial deposits in the Sugluk area of northern Ungava (Quebec, Canada). Review of Palaeobotany and Palynology 9 1969 45 61 Google Scholar
Boninsegna, J. A. Holmes, R. L. Breve descripción de un relicto de Austrocedrus chilensis (D. Don) Endl. en Huinganca (Pcia. del Neuquen). Anales Instituto Argentino Nivologia y Glaciologia (1977) 4 1978 115 124 Google Scholar
Boninsegna, J. A. Holmes, R. Distribución geografica de Araucaria araucana (Moll) C. Koch en relación a sus caracteristicas dendrocronologicas. Anales Instituto Argentino Nivologia y Glaciologia (1977) 4 1978 107 114 Google Scholar
Bradbury, J. P. Whiteside, M. C. Paleolimnology of two lakes in the Klutlan Glacier region, Yukon Territory, Canada. Quaternary Research 14 1980 149 168 Google Scholar
Brugman, R. B. The relationship between fossil diatom assemblages and limnological conditions. Hydrobiologia 98 1983 223 235 Google Scholar
Donoso, C. Z. Tipos Forestales de los Bosques Nativos de Chile 1981 1 70 Investigacion y Desarrollo Forestal, Documento de Trabajo 38 Google Scholar
Faegri, K. Iversen, I. Textbook of Pollen Analysis 1975 Hafner New York Google Scholar
Fernandez, J. El limite boreal de los bosques Andino-Patagonicos. Boletin Sociedad Argentina de Botanica 17 1976 307 314 Google Scholar
Haworth, E. Y. Two late-glacial (late Devensian) diatom assemblage profiles from northern Scotland. New Phytologist 77 1976 227 256 Google Scholar
Heusser, C. J. Quaternary pollen record from Laguna Tagua Tagua, Chile. Science (Washington, DC) 220 1983 1492 Google Scholar
LaMarche, V. C. Holmes, R. L. Dunwiddie, P. W. Drew, L. G. Tree Ring Chronologies of the Southern Hemisphere. 1. Argentina 1979 Laboratory Tree Ring Research Tucson, AR Chronology Series V. Google Scholar
Markgraf, V. Late and postglacial vegetational and paleoclimatic changes in subantarctic, temperate, and arid environments in Argentina. Palynology 7 1983 43 70 Google Scholar
Markgraf, V. Late Pleistocene and Holocene vegetation history of temperate Argentina: Lago Morentino, Bariloche. Dissertationes Botanicae (Festschrift Welten) 72 1984 235 254 Google Scholar
Markgraf, V. Paleoenvironmental history of the last 10,000 years in northwestern Argentina. Zentralblatt Geologie Palaeontologie I 11/12 1984 1985 1739 1749 Google Scholar
Markgraf, V. Late Pleistocene faunal extinctions in southern Patagonia. Science (Washington DC) 228 1985 1110 1112 CrossRefGoogle ScholarPubMed
Markgraf, V. D'Antoni, H. L. Pollen Flora of Argentina 1978 Univ. of Arizona Press Tucson Google Scholar
Mode, W. N. Quaternary Stratigraphy and Palynology of the Clyde Foreland, Baffin Island, N.W.T., Canada. Ph.D. dissertation 1980 University of Colorado Google Scholar
OMM/WMO/UNESCO Hoffman, J.A.J. Climatologic Atlas of South America. 1975 UNESCO Geneva Google Scholar
Pittock, A. B. Patterns of climatic variation in Argentina and Chile. I. Precipitation 1931–1960. Monthly Weather Review 108 1980 1347 1362 2.0.CO;2>CrossRefGoogle Scholar
Rodriguez, R. R. Matthei, O. Quesada, M. Flora Arborea de Chile 1983 Ed. de la Universidad de Concepción Chile Google Scholar
Schmithüsen, J. Die Nadelhölzer in den Waldgesellschaften der südlichen Anden. Vegetatio 9 1960 313 327 Google Scholar
Tortorelli, L. A. Maderas y Bosques Argentinos 1956 ACME Buenos Aires Google Scholar
Tranquillini, W. Physiological Ecology of the Alpine Timberline 1979 Springer Berlin Google Scholar
Veblen, T. T. Donoso, C. Z. Schlegel, F. M. Escobar, B. R. Forest dynamics in south-central Chile. Journal Biogeography 8 1981 211 247 CrossRefGoogle Scholar
Walter, H. Lieth, H. Klimadiagramm-Weltatlas 1967 Jena, Germany Google Scholar