Introduction

Information Sources

Biodiversity

Origins of Present Flora

Plant Communities and their Classification

Ecoregions

Plant Succession

Use of Plants by the Vuntut Gwitchin

Rare Plants

Resource Evaluation

Appendix 1 Vascular Plants

Bibliography

ECOREGIONS

The landscapes of Vuntut National Park were classified into two major ecoregions, the Northern Mountain Ecoregion and Old Crow Basin Ecoregion, in the system used by Wiken et al. (1981). Ecoregions were subdivided into ecodistricts (Figure 10.6). The Old Crow Basin Ecoregion included the Old Crow Flats as well as the Old Crow Pediments and Thomas Creek, the northwestern portion of the transition from the Northern Mountains to the Old Crow Flats.

A new system classifies the Park area within three Ecoregions: the British-Richardson Mountains Ecoregion, the Old Crow Flats Ecoregion and the Old Crow Basin Ecoregion (YEWG 2000). The main difference in comparison to the Wiken et al. system is that the Old Crow Flats has been made an ecoregion (Figure 10.6).

The following discussion of the vegetation of Vuntut National Park uses the three new ecoregions but also relies on the ecodistricts of Wiken et al. (1981) for details as the new system does not include ecodistricts. (See Appendix of Ecology, for more explanation of ecodistricts.)

1. Old Crow Flats Ecoregion

The vegetation of the Old Crow Flats is a complex mixture of wetland, riparian (river), and aquatic community types, along with tussock/medium shrub tundra communities in upland areas.

The lakes and ponds contain a variety of submerged and emergent species, water lily, marestail, and sedges. Most rivers and streams are lined with white spruce, feltleaf willow, balsam poplar, and sometimes paper birch. The understory is largely glandular birch, beautiful willow, and other willows. Dense thickets of feltleaf and other willows characterize the more recent alluvial terraces of meandering streams and rivers. Vegetation in upland sites consists of sheathed cottongrass, Labrador tea, shrub (glandular) birch, and sphagnum moss. Plant communities on "fossil" lake beds are shown in Figure 10.7.


Figure 10.7 Click photos to enlarge.

2. Old Crow Basin Ecoregion

The approximate northern limit of trees (treeline) roughly follows the boundary between the northern Old Crow Flats Ecoregion and the Old Crow Basin Ecoregion, crossing in a roughly east-west line before looping north to enclose the treed areas in the Firth River valley. In the northern part, sedge tussocks and low to medium shrubs are the predominant vegetation. To the south, tall shrubs and open parkland-like stands of white spruce are more common. Vegetation is generally lush and continuous. In wetlands, mosses and sedges are typical.

Vuntut Thomas Creek Ecodistrict

This area is a transition area from the Old Crow Flats Ecoregion to the British-Richardson Mountains Ecoregion. The typical vegetation of this ecodistrict is taiga; open stands of white spruce on the southern exposures of the lower slopes and foothills, and feltleaf willow, white spruce, and balsam poplar (cottonwood) along streams. Alpine tundra species (mountain avens, bearberry, netted willow etc.) form the understory on colluvium, and tussock vegetation (dwarf and shrub birch, sheathed cottongrass, Labrador tea, and bog cranberry and alpine blueberry and mosses probably form the understory on fans and pediments. Alpine tundra is sparse to discontinuous on the higher summits.

Vuntut Timber Creek Ecodistrict

Only the southern half of this ecodistrict, the part drained by Timber Creek, is within the Park. North of the continental divide, the waters flow to the arctic ocean via Muskeg Creek, Firth River, and Babbage River. The main type of vegetation in this ecodistrict is the tussock/low-to-medium shrub tundra, characterized by the sedge Carex microchaeta and/or tussocky cottongrass, along with Labrador tea, alpine bearberry, lapland rosebay, dwarf birch, netted and beautiful willows, and mosses. The striking pattern of the streams and drainageways is accentuated by the contrast between the natural colours of the dark green sedge and willow vegetation that follows them and the lighter yellow-brown and orange of the tussock/low shrub tundra that occurs between them.

The lower part of the gentle mountain slopes are well-vegetated while the upper slopes have patches and stripes of vegetation. The characteristic species include mountain avens Dryas octopetala, dwarf birch Betula nana, black crowberry, and alpine bearberry. Thickets of willow Salix alaxensis and other willows are found along streams with a coarse-textured floodplain. Willows (Salix pulchra, Salix glauca and others) also dominate stream borders and sedges may be abundant in poorly drained lowland areas around stream channels.

Vuntut Old Crow Pediments Ecodistrict

This extensive area to the east of the Old Crow Flats consists mainly of alternating tussock/low-to-medium shrub tundra and heathlands. In the tussocky area the vegetation is sheathed cottongrass, Labrador tea, shrub birch, widely scattered spruce, and mosses. On drier sites, crowberry, bog cranberry, alpine blueberry, and various willows are locally abundant. The vegetation of the heathlands is alder, willow, alpine blueberry, Labrador tea, and scattered spruce. Along the streams, spruce, Alaska and other willows become denser as the streams near the Flats.

Vuntut Blow Pass Ecodistrict

Although this ecodistrict only just extends into the northeastern Old Crow Flats Special Management Area at the headwaters of the Blow River, it is included as it is the main opening through which coastal weather reaches the Old Crow Basin. Most of the area is sedge-heath covered, but rock outcrops and stone-centered hummocks are common and the rest is tussock-covered pediments. In the foothills of the Barn Range and Richardson Mountains, and in the "Pass" itself, there is the typical higher elevation vegetation of dwarf birch, bog blueberry (V. uliginosum), Labrador tea (Ledum palustre), and alpine bearberry.

Vuntut Old Crow Range Ecodistrict

In the south part of the Ecoregion the Old Crow Range is an area of subdued relief in comparison to the British-Richardson Mountains. This area falls in the Old Crow Flats Special Management Area and is part of the barrier protecting the Old Crow Basin and Flats in the south. Ridge tops are relatively poorly vegetated with lichens, mountain avens and low willows being the main plants. 

Barren patches and tors are common on summit bedrock exposures. Sparse tundra covers many hilltops. Cottongrass tussocks and low to medium shrubs, along with scattered stunted white spruce, cover the valleys. Feltleaf and other willows and scattered spruce are found along stream margins. Figure 10.8 illustrates dwarf willow communities in the Old Crow Range.


Figure 10.8.  Click figure to enlarge and see another photo.

3. British-Richardson Mountains Ecoregion

The vegetation of this Ecoregion consists primarily of arctic and alpine tundra. Arctic tundra is characterized by continuous cover, with sedge tussocks along with an understory of shrubs and heath of low to medium height, often paralleling if not exceeding the sedges in height. Alpine tundra is discontinuous and sparse, with crustose lichens and forbs (largely mountain avens and alpine bearberry) predominating.

Vuntut Riggs Mountain Ecodistrict

The mountainous northwestern corner of Vuntut National Park extends into this ecodistrict. Here the vegetation is alpine tundra, with relatively high cover of mountain avens (Dryas) and sedges on rounded ridges and gentle slopes. Cover is more limited on steeper slopes, characterized by mats and stripes of vegetation composed of avens, moss campion, northern yellow oxytrope (Oxytropis campestris), draba, and the grass, alpine fescue (Festuca brachyphylla).

Vuntut Whitefold Hills Ecodistrict

This ecodistrict is characterized by alpine tundra vegetation consisting of widely scattered and sparse patches and stripes of mountain avens, alpine bearberry, and different kinds of saxifrages. On the lower undulating slopes, broader patches and stripes of vegetation include mountain avens, dwarf birch, sedges, netted willow, black crowberry, and lichens, particularly Cetraria cucullata and Thamnolia vermicularis. On south-facing slopes, white spruce is abundant.

Below the hills, the fans and pediments are covered by extensive tussocks and low shrubs.

Thickets of willow are found on coarse-grained floodplains and on other stream floodplains and borders, willow thickets are found with lupines, wild rhubarb ts'iigyuu (Polygonum) and grasses. Drainageways are dominated by beautiful willow, shrub (glandular) birch (Betula grandulosa) and narrow-leaved cottongrass.

Vuntut Blackfold Hills Ecodistrict

As most of the ecodistrict originally described by Wiken et al. (1981) is outside of Vuntut National Park, it is not possible to summarize the vegetation from their description. In general, treeless tundra covers the surface of the upland areas and tussock and low to medium shrub tundra covers the extensive pediments and fans.

Vuntut West Barn Range Ecodistrict

This ecodistrict is very similar to the Whitefold Mountains and was only separated out for ease in data handling (Wikens et al. 1981). Vegetation is basically identical to the description for the Whitefold Hills. Figure 10.9 illustrates plant communities in the Barn and British Mountains.


Figure 10.9 Click on figure to enlarge and see other photos.

Vuntut Bonnet Lake Ecodistrict

This transition region from the Old Crow Flats to the Richardson Mountains, which does not occur in Vuntut National Park, only the Special Management Area, is an extensive plateau of low hills and wide valleys. The primary vegetation cover is tussock-low tundra characterized by cottongrass, sedges, dwarf birch, beautiful willow, V. uliginosum, Labrador tea, alpine bearberry and mosses.