Mountain Park: a plant refugium in the Canadian Rocky Mountains

1974 ◽  
Vol 52 (6) ◽  
pp. 1393-1409 ◽  
Author(s):  
John G. Packer ◽  
Dale H. Vitt
Keyword(s):  
Rocky Mountains ◽  
Flowering Plants ◽  
Canadian Rocky Mountains ◽  
Present Distribution ◽  
Angiosperm Species

It is suggested that the area in the vicinity of Mountain Park, Alberta, (52°50′ N; 117°20′ W) in the Canadian Rocky Mountains was a refugium during the Wisconsin period, where alpine and montane bryophytes and flowering plants survived the glaciation in situ. Evidence for this view includes data derived from geological investigations and from the present distribution of a number of bryophyte and angiosperm species. Alternative explanations to account for these distributions are discussed and reasons for rejecting them as highly improbable are presented.

Using 10Be dating to determine when the Cordilleran Ice Sheet stopped flowing over the Canadian Rocky Mountains

2021 ◽  
pp. 1-12
Author(s):  
Helen E. Dulfer ◽  
Martin Margold ◽  
Zbynĕk Engel ◽  
Régis Braucher ◽  
Aster Team
Keyword(s):  
Rocky Mountains ◽  
Ice Sheet ◽  
Mountain Range ◽  
Canadian Rocky Mountains ◽  
Weighted Mean ◽  
Exposure Age ◽  
Western Side ◽  
Cordilleran Ice Sheet ◽  
The Last Glacial

Abstract During the last glacial maximum the Cordilleran and Laurentide ice sheets coalesced east of the Rocky Mountains and geomorphological evidence indicates ice flowed over the main ridge of the Rocky Mountains between ~54–56°N. However, this ice flow has thus far remained unconstrained in time. Here we use in situ produced cosmogenic 10Be dating to determine when Cordilleran ice stopped flowing over the mountain range. We dated eight samples from two sites: one on the western side (Mount Morfee) and one on the eastern side (Mount Spieker) of the Rocky Mountains. At Mount Spieker, one sample is rejected as an outlier and the remaining three give an apparent weighted mean exposure age of 15.6 ± 0.6 ka. The four samples at Mount Morfee are well clustered in time and give an apparent weighted mean exposure age of 12.2 ± 0.4 ka. These ages indicate that Mount Spieker became ice free before the Bølling warming and that the western front of the Rocky Mountains (Mount Morfee) remained in contact with the Cordilleran Ice Sheet until the Younger Dryas.

Regulation of Rotifers by Predatory Calanoid Copepods (Subgenus Hesperodiaptomus) in Lakes of the Canadian Rocky Mountains

1994 ◽  
Vol 51 (11) ◽  
pp. 2520-2528 ◽  
Author(s):  
Andrew J. Paul ◽  
David W. Schindler
Keyword(s):  
Rocky Mountains ◽  
Logistic Regression Model ◽  
Calanoid Copepod ◽  
Alpine Lakes ◽  
Canadian Rocky Mountains ◽  
Calanoid Copepods ◽  
Order Of Magnitude ◽  
Keratella Quadrata ◽  
Planktonic Rotifers

The abundance of planktonic rotifers in alpine lakes is regulated by predation from Diaptomus (subgenus Hesperodiaptomus) arcticus (a large calanoid copepod) regardless of nutrient conditions. We manipulated both predators and nutrient levels in large in situ enclosure experiments (2250 L). Hesperodiaptomus arcticus suppressed densities of the soft-bodied rotifer Polyarthra dolichoptera significantly (two to three orders of magnitude) and the loricate rotifer Keratella quadrata less so (up to one order of magnitude) relative to populations in predator-free enclosures. Keratella quadrata's armoured lorica may limit predation by Hesperodiaptomus. Nutrient addition resulted in higher phytoplankton standing crops and rotifer densities but did not permit rotifers to exceed predator consumption. In 69 lakes from the Canadian Rocky Mountains, the presence of Keratella or Polyarthra was negatively correlated with Hesperodiaptomus density. A maximum-likelihood logistic regression model predicts that as Hesperodiaptomus densities increase the probability of occurrence for both rotifer genera decreases, with Polyarthra declining more rapidly than Keratella.

scholarly journals Evidence for Headwall Weathering Zones, Boundary Glacier, Canadian Rocky Mountains

1987 ◽  
Vol 33 (113) ◽  
pp. 60-67 ◽  
Author(s):  
James S. Gardner
Keyword(s):  
Temperature Regime ◽  
Rocky Mountains ◽  
Freezing Temperature ◽  
Rock Surface ◽  
Canadian Rocky Mountains ◽  
Freeze Thaw ◽  
Thaw Zone ◽  
Potential Factor ◽  
Temperature Records

AbstractTemperature records from several randkluft sites at the margins and headwall of Boundary Glacier (lat. 52° 12′ N., long. 117° 12′ W.) in the Canadian Rocky Mountains are presented. These records indicate that during the ablation season a diurnal freeze-thaw air and rock-surface temperature regime occurs in a 2 m wide zone centred on the randkluft lip. Deeper in the randkluft, stable sub-zero conditions prevail whereas above the randkluft an above-freezing temperature regime prevails. The freeze-thaw temperature regime, observed freezing of melt water and rain water on randkluft rock surfaces, and copious in-situ loose weathering products on the headwall and marginal free faces suggest an active frost-shattering environment. Down-slope migration of the randkluft lip during the ablation season results in a migration of the freeze-thaw zone and thus a seasonal extension of the rock surface area exposed to the favorable weathering environment. Longer-term glacier fluctuations, with attendant thinning and thickening of the ice body, could result in large areas of marginal and headwall rock surfaces being exposed to the randkluft weathering environment over long periods of time. The data and observations from Boundary Glacier support an idea, suggested by Battle (1960), that open and shallow randklufts, rather than closed and deep bergschrunds, are a focus of weathering at glacier margins and thus a potential factor in cirque development.

scholarly journals Evidence for Headwall Weathering Zones, Boundary Glacier, Canadian Rocky Mountains

1987 ◽  
Vol 33 (113) ◽  
pp. 60-67 ◽  
Author(s):  
James S. Gardner
Keyword(s):  
Temperature Regime ◽  
Rocky Mountains ◽  
Freezing Temperature ◽  
Rock Surface ◽  
Canadian Rocky Mountains ◽  
Freeze Thaw ◽  
Thaw Zone ◽  
Potential Factor ◽  
Temperature Records

AbstractTemperature records from severalrandkluftsites at the margins and headwall of Boundary Glacier (lat. 52° 12′ N., long. 117° 12′ W.) in the Canadian Rocky Mountains are presented. These records indicate that during the ablation season a diurnal freeze-thaw air and rock-surface temperature regime occurs in a 2 m wide zone centred on therandkluftlip. Deeper in therandkluft, stable sub-zero conditions prevail whereas above therandkluftan above-freezing temperature regime prevails. The freeze-thaw temperature regime, observed freezing of melt water and rain water onrandkluftrock surfaces, and copiousin-situloose weathering products on the headwall and marginal free faces suggest an active frost-shattering environment. Down-slope migration of therandkluftlip during the ablation season results in a migration of the freeze-thaw zone and thus a seasonal extension of the rock surface area exposed to the favorable weathering environment. Longer-term glacier fluctuations, with attendant thinning and thickening of the ice body, could result in large areas of marginal and headwall rock surfaces being exposed to therandkluftweathering environment over long periods of time. The data and observations from Boundary Glacier support an idea, suggested by Battle (1960), that open and shallowrandklufts, rather than closed and deep bergschrunds, are a focus of weathering at glacier margins and thus a potential factor in cirque development.

Wildfires in the southern Canadian Rocky Mountains and their relationship to mid-tropospheric anomalies

1993 ◽  
Vol 23 (6) ◽  
pp. 1213-1222 ◽  
Author(s):  
E.A. Johnson ◽  
D.R. Wowchuk
Keyword(s):  
North America ◽  
Rocky Mountains ◽  
Large Scale ◽  
Fire Frequency ◽  
Fuel Moisture ◽  
Large Fire ◽  
Canadian Rocky Mountains ◽  
Area Burned ◽  
Upper Level ◽  
Moisture Conditions

In this paper we present evidence for a large-scale (synoptic-scale) meteorological mechanism controlling the fire frequency in the southern Canadian Rocky Mountains. This large-scale control may explain the similarity in average fire frequencies and timing of change in average fire frequencies for the southern Canadian Rocky Mountains. Over the last 86 years the size distribution of fires (annual area burned) in the southern Canadian Rockies was distinctly bimodal, with a separation between small- and large-fire years at approximately 10–25 ha annual area burned. During the last 35 years, large-fire years had significantly lower fuel moisture conditions and many mid-tropospheric surface-blocking events (high-pressure upper level ridges) during July and August (the period of greatest fire activity). Small-fire years in this period exhibited significantly higher fuel moisture conditions and fewer persistent mid-tropospheric surface-blocking events during July and August. Mid-tropospheric surface-blocking events during large-fire years were teleconnected (spatially and temporally correlated in 50 kPa heights) to upper level troughs in the North Pacific and eastern North America. This relationship takes the form of the positive mode of the Pacific North America pattern.

Canadian Rocky Mountains

1903 ◽  
Vol 21 (6) ◽  
pp. 685
Author(s):  
J. Norman Collie
Keyword(s):  
Rocky Mountains ◽  
Canadian Rocky Mountains

Spatial and temporal variations of fire regimes in the Canadian Rocky Mountains and Foothills of southern Alberta

2016 ◽  
Vol 25 (11) ◽  
pp. 1117 ◽  
Author(s):  
Marie-Pierre Rogeau ◽  
Mike D. Flannigan ◽  
Brad C. Hawkes ◽  
Marc-André Parisien ◽  
Rick Arthur
Keyword(s):  
Rocky Mountains ◽  
Fire History ◽  
Fire Severity ◽  
Ecological Integrity ◽  
Fire Regimes ◽  
Temporal Variations ◽  
Fire Season ◽  
Canadian Rocky Mountains ◽  
Southern Alberta ◽  
Fire Exclusion

Like many fire-adapted ecosystems, decades of fire exclusion policy in the Rocky Mountains and Foothills natural regions of southern Alberta, Canada are raising concern over the loss of ecological integrity. Departure from historical conditions is evaluated using median fire return intervals (MdFRI) based on fire history data from the Subalpine (SUB), Montane (MT) and Upper Foothills (UF) natural subregions. Fire severity, seasonality and cause are also documented. Pre-1948 MdFRI ranged between 65 and 85 years in SUB, between 26 and 35 years in MT and was 39 years in UF. The fire exclusion era resulted in a critical departure of 197–223% in MT (MdFRI = 84–104 years). The departure in UF was 170% (MdFRI = 104 years), while regions of continuous fuels in SUB were departed by 129% (MdFRI = 149 years). The most rugged region of SUB is within its historical range of variation with a departure of 42% (MdFRI = 121 years). More mixed-severity burning took place in MT and UF. SUB and MT are in a lightning shadow pointing to a predominance of anthropogenic burning. A summer fire season prevails in SUB, but occurs from spring to fall elsewhere. These findings will assist in developing fire and forest management policies and adaptive strategies in the future.

New Lower Jurassic ammonite faunas from the Fernie Formation, southern Canadian Rocky Mountains

1987 ◽  
Vol 24 (8) ◽  
pp. 1688-1704 ◽  
Author(s):  
Russell L. Hall
Keyword(s):  
British Columbia ◽  
North American ◽  
Rocky Mountains ◽  
Red Deer ◽  
First Record ◽  
Lower Jurassic ◽  
Canadian Rocky Mountains ◽  
Poker Chip

New ammonite faunas are described from sections along Bighorn and Scalp creeks in central-western Alberta where Lower Jurassic parts of the Fernie Formation are exposed. The first record of the upper Sinemurian Obtusum Zone from the Fernie is based on the occurrence of Asteroceras cf. stellare and Epophioceras cf. breoni in the basal pebbly coquina on Bighorn Creek. The overlying Red Deer Member has yielded Amaltheus cf. stokesi, representing the upper Pliensbachian Margaritatus Zone; in immediately superjacent strata the first North American examples of ?Amauroceras occur together with Protogrammoceras and ?Aveyroniceras. In the basal parts of the overlying Poker Chip Shale a fauna including Harpoceras cf. falciferum, Harpoceratoides, Polyplectus cf. subplanatus, Hildaites cf. serpentiniformis, and Dactylioceras cf. athleticum is correlated with the lower Toarcian Falciferum Zone.The upper parts of the Poker Chip Shale on Fording River in southeastern British Columbia contain a fauna representing some part of the upper Toarcian, but owing to poor preservation, generic identifications are only tentatively made.

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