Late Quaternary environmental change in the Lake O'Hara region, Yoho National Park, British Columbia

Reasoner, Mel A.; Hickman, Michael

doi:10.1016/0031-0182(89)90149-1

Cited by 57 publications

(41 citation statements)

References 42 publications

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“…Two of these (Hazell, 1979;Hebda, described in detail herein) come from the low to mid-elevations of the RMT, three (Kearney and Luckman, 1983;Fergusson and Hills, 1985;Reasoner and Hickman, 1989) represent sites in the Rocky Mountains, and one (Hebda, unpublished) represents moist mid-elevation forests of the western edge of the region.…”

Section: Columbia Mountains and Southern Rockiesmentioning

confidence: 99%

British Columbia Vegetation and Climate History with Focus on 6 ka BP

Hebda¹

2007

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132

104

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British Columbia Holocene vegetation and climate is reconstructed from pollen records. A coastal Pinus contorta paleobiome developed after glacier retreat under cool and probably dry climate. Cool moist forests involving Picea, Abies, Tsuga spp., and Pinus followed until the early Holocene. Pseudotsuga menziesii arrived and spread in the south 10 000-9000 BP, and Picea sitchensis - Tsuga heterophylla forests developed in the north. T. heterophylla increased 7500-7000 BP, and Cupressaceae expanded 5000-4000 BP. Bogs began to develop and expland. Modern vegetation arose 4000-2000 BP. There were early Holocene grass and Artemisia communities at mid-elevations and pine stands at high elevations in southern interior B.C. Forests expanded downslope and lakes formed 8500-7000 BP. Modern forests arose 4500-4000 BP while lower and upper tree lines declined. In northern B.C. non-arboreal communities preceded middle Holocene Picea forests. Abies, Pinus and Picea mariana predominated at various sites after 4000 BP. At 6000 BP Tsuga heterophylla (south) and Picea sitchensis (north) dominated the coast and islands and Quercus garryana and Pseudotsuga on southeast Vancouver Island, but Thuja plicata was infrequent. Southern Interior Plateau vegetation at 6000 BP was more open than today at middle to lower elevations, whereas forests covered the Northern Interior Plateau. Picea forests occurred in northern B.C. Holocene climate phases were: 1) warm dry "xerothermic" ca. 9500-7000 BP, 2) warm moist "mesothermic" ca. 7000-4500 BP, 3) moderate and moist 4500-0 BP, with increasing moisture 8500-6000 BP and cooling (?increased moisture) 4500-3000 BP. B.Cs Hypsithermal had dry and wet stages; 6000 BP occurred in the warm and wet mesothermic stage.Cette reconstitution a été effectuée à partir des données polliniques. Un paléobiome à Pinus contorta s'est établi après le retrait des glaciers sous un climat frais et probablement sec. Des forêts de climat frais et humide à dominance de Picea, Abies, Tsuga spp. et Pinus ont suivi, jusqu'à l'Holocène inférieur. Pseudotsuga menziesii s'est ensuite répandu dans le sud de 10 000 à 9000 BP, tandis que les forêts à Picea sitchensis - Tsuga heterophylla se sont répandues dans le nord. T. heterophylla s'est accru de 7500 à 7000 BP et Cupressaceae s'est répandu de 5000 à 4000 BP. La végétation moderne s'est manifestée de 4000-2000 BP. Dans le sud de la partie intérieure, il y a eu des herbes et des communautés d'Artemisia aux altitudes moyennes et des peuplements de pins en haute altitude au début de l'Holocène. Les forêts modernes se sont formées de 4500 à 4000 BP, tandis que les limites des arbres déclinaient. Au nord, les communautés non arboréennes ont précédé les forêts de pins de l'Holocène moyen. Abies, Pinus et Picea mariana ont prédominé en différents sites après 4000 BP. À 6000 BP, Tsuga heterophylla (au sud) et Pinus sitchensis (au nord) ont dominé sur les côtes et les îles et Quercus garryana ainsi que Pseudotsuga, le sud-est de l'île de Vancouver. La végétation du sud du plateau intérie...

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Section: Columbia Mountains and Southern Rockiesmentioning

confidence: 99%

British Columbia Vegetation and Climate History with Focus on 6 ka BP

Hebda¹

2007

gpq

132

104

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“…This early Pinus-dominated forest included persistent areas of open vegetation. A similar pattern is evident at Lake O'Hara (Reasoner and Hickman, 1989), Copper Lake and Kingfisher Pond (White, 1987), Yamnuska Bog and Wedge Lake (MacDonald, 1982). Together, these palaeoenvironmental reconstructions from alpine sites in western Canada indicate that the interval from 10 000 to 7000 BP was a period of relative warmth associated with elevated alpine timberlines.…”

Section: Vegetationmentioning

confidence: 60%

“…In the mountains, essentially modern plant communities become established around 5000 BP (Luckman and Kearney, 1986;Reasoner and Huber, 1999) although there is evidence for a neoglacial advance starting approximately 3000 BP (Reasoner and Hickman, 1989). A similar pattern is recorded for the Foothills (MacDonald, 1989) while Sauchyn and Sauchyn (1991) document increases in forest cover around Harris Lake starting as early as 5000 BP.…”

Section: Vegetationmentioning

confidence: 62%

“…At Crowfoot Lake, the pollen and macroscopic remains in Zone 1, dating from 11 330 to 10 100 BP, suggest a sparsely vegetated, unstable landscape associated with recently deglaciated terrain in the upper Bow Valley. Comparable vegetation communities are represented for roughly the same interval in pollen cores from Lake O'Hara (Reasoner and Hickman, 1989), Copper Lake and Kingfisher Pond (White, 1987), and Yamnuska Bog (MacDonald, 1982). In the Foothills at Toboggan Lake, the local vegetation at this time is generally sparse and dominated by herbs and shrubs, namely Artemisia and Gramineae (MacDonald, 1989).…”

Section: Vegetationmentioning

confidence: 99%

“…In the mountain valleys, for example, the treeline attained its highest level between 8500 and 7000 BP (Reasoner and Hickman, 1989) whereas a gradual replacement of forest by prairie occurred in the Foothills between 8500 and 5000 BP (e.g., MacDonald, 1989). In the Parklands, grass pollen becomes increasingly common in the Lofty Lake core between 9000 and 6000 BP (Vance, 1986) whereas a similar change in vegetation is recorded in the Harris Lake core for the interval dating between 7700 and 6800 BP.…”

Section: Vegetationmentioning

confidence: 99%

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River of Change: a Model for the Development of Terraces Along the Bow River, Alberta

Oetelaar

2004

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Researchers working in the Bow River valley have identified a minimum of four alluvial terraces, the upper two of which have been designated as paired terraces. Over the past 35 years, they have attempted to correlate these alluvial landforms and to generate models for the development of the terraces along the section of the Bow River between Calgary and the Rocky Mountains. In this study, Mazama ash and an early Holocene paleosol are used to correlate the terrace suites examined by previous researchers and to generate a model which accounts for the development of the upper two sets of paired terraces. These paired terraces reflect major episodes of aggradation and degradation that result from changes in independent variables such as climate and uplift. The initial episode of aggradation, dating from the late Pleistocene, is the result of paraglacial processes in a sparsely vegetated, yet saturated environment. Following a brief episode of degradation at the end of the Younger Dryas, the second episode of aggradation, dating from 9000 to 5000 BP, is caused by increased sediment load and lowered stream power during the Hypsithermal.Les chercheurs travaillant dans la vallée de la rivière Bow ont identifié au moins quatre terrasses alluviales, dont les deux supérieures ont été identifiées comme étant appariées. Au cours des 35 dernières années, ils ont essayé de corréler entre elles ces formes alluviales et d’élaborer des modèles appropriés à la formation des terrasses le long de la Bow River, entre Calgary et les Rocheuses. Dans la présente étude, les cendres de Mazama et un paléosol de l’Holocène inférieur ont servi à faire la corrélation entre les ensembles de terrasses étudiés précédemment et à élaborer un modèle pouvant expliquer la formation des deux ensembles supérieurs de terrasses appariées. Ces dernières résultent d’épisodes importants d’alluvionnement et de déblaiement qu’ont entraînées des modifications apportées à des phénomènes agissant de façon indépendante, comme le climat et le relèvement isostasique. Le premier épisode d’alluvionnement, survenu au Pléistocène supérieur, est le résultat de processus paraglaciaux agissant dans un milieu présentant une végétation clairsemée, bien que saturé. Après un court épisode de déblaiement à la fin du Dryas inférieur, le deuxième épisode d’alluvionnement (9000-5000 BP) est provoqué par une augmentation de la charge solide dans un cours d’eau de faible compétence, à l’Hypsithermal.Los estudios hechos en el valle del Bow River identifican por lo menos 4 terrazas fluviales, las dos terrazas superiores son consideradas terrazas apareadas. Durante los últimos 35 años se ha intentado relacionar estos relieves fluviales y generar modelos que permitan explicar la formación de terrazas a lo largo de la sección del Bow River entre Calgary y las Rocosas. En este estudio, las cenizas de Mazama y análisis de paleosuelos datando del Holoceno temprano han sido empleados para establecer una correlación de la serie de terrazas examinadas con anterioridad y así generar un modelo ...

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Assessment of Climate Change and Freshwater Ecosystems of the Rocky Mountains, Usa and Canada

et al. 1997

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The Rocky Mountains in the USA and Canada encompass the interior cordillera of western North America, from the southern Yukon to northern New Mexico. Annual weather patterns are cold in winter and mild in summer. Precipitation has high seasonal and interannual variation and may dier by an order of magnitude between geographically close locales, depending on slope, aspect and local climatic and orographic conditions. The region's hydrology is characterized by the accumulation of winter snow, spring snowmelt and autumnal base¯ows. During the 2±3-month`spring runo' period, rivers frequently discharge 470% of their annual water budget and have instantaneous discharges 10±100 times mean low¯ow.Complex weather patterns characterized by high spatial and temporal variability make predictions of future conditions tenuous. However, general patterns are identi®able; northern and western portions of the region are dominated by maritime weather patterns from the North Paci®c, central areas and eastern slopes are dominated by continental air masses and southern portions receive seasonally variable atmospheric circulation from the Paci®c and the Gulf of Mexico. Signi®cant interannual variations occur in these general patterns, possibly related to ENSO (El NinÄ o±Southern Oscillation) forcing.Changes in precipitation and temperature regimes or patterns have signi®cant potential eects on the distribution and abundance of plants and animals. For example, elevation of the timber-line is principally a function of temperature. Palaeolimnological investigations have shown signi®cant shifts in phyto-and zoo-plankton populations as alpine lakes shift between being above or below the timber-line. Likewise, streamside vegetation has a signi®cant eect on stream ecosystem structure and function. Changes in stream temperature regimes result in signi®cant changes in community composition as a consequence of bioenergetic factors. Stenothermic species could be extirpated as appropriate thermal criteria disappear. Warming temperatures may geographically isolate cole water stream ®shes in increasingly con®ned headwaters. The heat budgets of large lakes may be aected resulting in a change of state between dimictic and warm monomictic character. Uncertainties associated with prediction are increased by the planting of ®sh in historically ®shless, high mountain lakes and the introduction of non-native species of ®shes and invertebrates into often previously simple food-webs of large valley bottom lakes and streams. Many of the streams and rivers suer from the anthropogenic eects of abstraction and regulation. Likewise, many of the large lakes receive nutrient loads from a growing human population.We concluded that: (1) regional climate models are required to resolve adequately the complexities of the high gradient landscapes; (2) extensive wilderness preserves and national park lands, so prevalent in the Rocky Mountain Region, provide sensitive areas for dierentiation of anthropogenic eects from climate eects; and (3) future research should ...

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Late Quaternary environmental change in the Lake O'Hara region, Yoho National Park, British Columbia

Cited by 57 publications

References 42 publications

British Columbia Vegetation and Climate History with Focus on 6 ka BP

British Columbia Vegetation and Climate History with Focus on 6 ka BP

River of Change: a Model for the Development of Terraces Along the Bow River, Alberta

Assessment of Climate Change and Freshwater Ecosystems of the Rocky Mountains, Usa and Canada

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