Native-induced secondary plant succession in the Mackenzie River delta, Northwest Territories, Canada

Polar Record ◽  
1973 ◽  
Vol 16 (105) ◽  
pp. 805-808
Author(s):  
Don Gill
Keyword(s):  
Picea Glauca ◽  
River Delta ◽  
Plant Succession ◽  
Minor Role ◽  
Mackenzie Delta ◽  
Populus Balsamifera ◽  
Point Bar ◽  
Flood Plains ◽  
Convex Section ◽  
Mackenzie River

Plants introduced by man play a very minor role in the flora of the Mackenzie River, delta and are primarily restricted to centres of habitation such as Inuvik, Aklavik, and Reindeer Station (Map 1) (Cody, 1965; Gill, 1971). Within the delta itself, however, a number of introduced species are recurringly present on one geomorphic position, the point bar, which forms the convex section of a meander bend in flood plains and deltas (Fig 1). The Mackenzie delta supports a northerly extension of the boreal forest, and most of the higher levees are occupied by trees, particularly White Spruce Picea glauca. Point bars are constructed of coarser alluvium than other delta landforms, thus they have a drier and warmer soil environment than other locations (Gill, 1972a); vegetation response to this locally ameliorated environment has been such that virtually every point bar in the Mackenzie delta is occupied by a discrete plant community dominated by Balsam Poplar Populus balsamifera (Gill, 1972b). The poplar stands are surprisingly well developed for such a northerly latitude, 68°45′N (Fig 2).

The Point Bar Environment in the Mackenzie River Delta

1972 ◽  
Vol 9 (11) ◽  
pp. 1382-1393 ◽  
Author(s):  
Don Gill
Keyword(s):  
Fine Fraction ◽  
River Delta ◽  
Plant Colonization ◽  
Populus Balsamifera ◽  
Point Bar ◽  
Balsam Poplar ◽  
Sediment Sorting ◽  
Point Bars ◽  
Lower Water Content ◽  
Mackenzie River

Helicoidal flow and sediment sorting along the convex portion of shifting channels in the Mackenzie River Delta cause point bars to be composed of the coarsest material available to plant colonization. Sorting by aeolian action further reduces the fine fraction in point bar soils. Coarse-textured deposits maintain a lower water content and a higher soil temperature than other deltaic surfaces, thus nearly every point bar is colonized by a discrete plant association. This ecosystem is dominated by balsam poplar (Populus balsamifera), and the distribution of well developed poplar stands is restricted to point bars. The successional ecology of this ecosystem is discussed in relation to the point bar environment.

Plant succession on an active tundra mud slump, Garry Island, Mackenzie River Delta, Northwest Territories

1976 ◽  
Vol 54 (15) ◽  
pp. 1750-1758 ◽  
Author(s):  
J. D. H. Lambert
Keyword(s):  
Principal Component ◽  
River Delta ◽  
Plant Succession ◽  
Second Stage ◽  
Stage Of Development ◽  
Third Stage ◽  
Natural Revegetation ◽  
Speed Up ◽  
Associated Species ◽  
Mackenzie River

The vegetation in the latter stages of an active mud slump of known age on Garry Island, Mackenzie River Delta, N.W.T., is described using principal-component analysis. Three associations are recognized. Senecio congestus and isolated hummocks with dwarf shrub – heath vegetation dominate during the first 4 years after exposure. The Arctagrostis latifolia – Senecio congestus association that dominates after 4 years represents the second stage of development after the disappearance of recognizable hummocks. The Arctagrostis latifolia – Eriophorum scheuchzeri association that dominates after 6 years is the third stage in the revegetation sequence and represents further stabilization of the mud slump surface. The frequency of hummock-associated species is greatly reduced. The rapid rate of natural revegetation, in such a mud slump where the headwall had been receding, would suggest that man-induced reseeding programs, in all probability, would not speed up the process.

scholarly journals The influence of river discharge on the thawing of sea ice, Mackenzie River Delta: albedo and temperature analyses

1994 ◽  
Vol 13 (1) ◽  
pp. 83-94 ◽  
Author(s):  
K. G. Dean ◽  
W. J. Stringer ◽  
K. Ahlnäs ◽  
C. Searcy ◽  
T. Weingartner
Keyword(s):  
Sea Ice ◽  
River Discharge ◽  
River Delta ◽  
Mackenzie River

Persistence of a scour hole on the East Channel of the Mackenzie Delta, N.W.T.

2000 ◽  
Vol 27 (4) ◽  
pp. 798-804 ◽  
Author(s):  
Steven R Fassnacht ◽  
F Malcolm Conly
Keyword(s):  
Average Rate ◽  
Temporal Stability ◽  
Mackenzie Delta ◽  
River Channels ◽  
Channel Stability ◽  
Practical Concern ◽  
Scour Hole ◽  
Lateral Erosion ◽  
Morphologic Data ◽  
Mackenzie River

Anomalies in the bathymetry of river channels are of great practical concern for designing sub-bed pipeline crossings. Of particular interest is the long-term stability of deep holes. Bathymetric evidence indicates that one unusually deep hole in the East Channel of the Mackenzie River, referred to as a scour hole, has existed as early as 1956. Detailed hydraulic and morphologic data were first collected in 1985, and again in 1992 to assess the spatial and temporal stability of the feature. Even with a record flood on the Mackenzie River in 1988, the hole, with a maximum depth approaching 30 m, was vertically stable over the 7-year period. However, lateral erosion and sedimentation have resulted in a shift in the horizontal position of the scour hole, with a maximum horizontal erosion of approximately 2 m/a. The average rate of lateral outward movement was observed to be 0.8 m/a.Key words: Mackenzie Delta, rivers, fluvial sediment, channel stability, scour, scour hole.

Mercury in the Mackenzie River delta and estuary: Concentrations and fluxes during open-water conditions

2009 ◽  
Vol 407 (8) ◽  
pp. 2980-2988 ◽  
Author(s):  
Jennifer A. Graydon ◽  
Craig A. Emmerton ◽  
Lance F.W. Lesack ◽  
Erin N. Kelly
Keyword(s):  
Open Water ◽  
River Delta ◽  
Water Conditions ◽  
Mackenzie River

scholarly journals Morphological and ecological variation among populations and subspecies of Burbot (Lota lota [L, 1758]) from the Mackenzie River Delta, Canada

2015 ◽  
Vol 128 (4) ◽  
pp. 377 ◽  
Author(s):  
Hans Recknagel ◽  
Amy Amos ◽  
Kathryn R. Elmer
Keyword(s):  
River Delta ◽  
Pungitius Pungitius ◽  
Local Conditions ◽  
Lota Lota ◽  
Phenotypic Differences ◽  
Carbon And Nitrogen ◽  
Stable Isotope Signatures ◽  
Morphological Differences ◽  
Eastern Edge ◽  
Mackenzie River

The Burbot (Lota lota [L, 1758]) is a holarctic distributed freshwater fish in the Gadidae family. In northwestern Canada, it has an important value for local and traditional fisheries. We describe the morphology and ecology of Burbot from four populations in the Mackenzie River Delta. Two subspecies come into contact in this area, which is the western edge of Lota lota maculosa distribution (one population in our study) and the eastern edge of Lota lota lota distribution (three populations in our study). We found the combined length–weight relationship in these four populations to be log10 (weight) = −3.986 + 2.617 * log10 (length). There was no difference in mean body length (overall mean and standard deviation 73.4 ± 8.7 cm), although the L. l. lota populations were heavier than the L. l. maculosa population. All populations differed in their carbon and nitrogen stable isotope signatures (δ15N overall mean 12.1 ± 1.59; δ13C overall mean −25.54 ± 1.11). Main prey items were four fish species: Ninespine Stickleback (Pungitius pungitius [L, 1758]), Broad Whitefish (Coregonus nasus [Pallas, 1776]), Burbot, and Northern Pike (Esox lucius [L, 1758]). Ecological and morphological differences may be due to local conditions and population variability or to the different Lota lota subspecies. More ecological and morphological information from this region is needed to resolve possible phenotypic differences between the subspecies.

The hydrologic regime of Mackenzie River and connection of "no-closure" lakes to distributary channels in the Mackenzie Delta, Northwest Territories

1995 ◽  
Vol 32 (7) ◽  
pp. 926-937 ◽  
Author(s):  
C. R. Burn
Keyword(s):  
Water Level ◽  
Drainage Basin ◽  
Late Summer ◽  
River System ◽  
Water Levels ◽  
Ice Thickness ◽  
Mackenzie Delta ◽  
Lake Ice ◽  
Discharge System ◽  
Mackenzie River

Mackenzie Delta lakes have been classified by the seasonal duration of their connection to Mackenzie River. "No-closure" lakes are determined on the basis of minimum summer water level. Such lakes may become disconnected from the Mackenzie in autumn or winter, as water level falls or if the sills between lakes and distributary channels are frozen through and so sealed. Water level in the central delta rises continuously after late November–early December, at first because discharge into the delta increases once the Mackenzie drainage basin has frozen over, and then as sea and channel ice thickens in the outer delta, impounding discharge. Since 1973 this seasonal increase in stage from its minimum in early December to the level on 1 April has been between 29 and 95 cm. Between 1987 and 1994, the rise in stage near Inuvik has been slightly greater than increases in lake-ice thickness (30–68 cm). Channels and lakes that are connected to the Mackenzie discharge system in December may remain connected throughout winter. A critical sill elevation for connection of such lakes to the river system is the minimum stage minus mid-December ice thickness. Recently, these elevations have been from 1.0 to 1.6 m lower than late summer water levels. Lakes with sill elevations still lower may remain connected to the Mackenzie throughout the year. In 1993-1994, only 3 of 16 "no-closure" lakes surveyed near Inuvik remained open to the Mackenzie discharge throughout winter, representing 2% of the lakes in this portion of the delta.

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