Scientific Name: Deschampsia mackenzieana
Taxonomy Group: Vascular Plants
Range: Northwest Territories, Saskatchewan
Last COSEWIC Assessment: November 2001
Last COSEWIC Designation: Special Concern
SARA Status: Schedule 1, Special Concern
Image of Mackenzie Hairgrass
This perennial grass species has densely tufted stems which grow from fibrous roots. The leaves are mostly basal, with narrow, involute or folded blades. The ligules are large, 3-5 mm long. The panicles are large, open, light straw-coloured, 10-20 cm long. The spikelets are 6-12 mm long, with 2 or 3 flowers. The glumes are narrowly lanceolate and 5-10 mm long, and the lemmas are glabrous, 4-6 mm long, with callus hairs 2-3 mm long. The anthers are over 2 mm long and the caryopses are about 2 mm long.
Distribution and Population
The species is endemic to Canada, with its total range restricted to the sand dunes on the south shore of Lake Athabasca in northwestern Saskatchewan. It is relatively frequent locally, occuring as scattered large tufts or in small groups of 3-5 or more plants. The overall cover of the plants over the larger dune fields is estimated at about 0.1%. A very rough population estimate is >300,000 plants. There is no indication that the population is declining.
The plants occur in large, open, active sand-dunes, where they are found mostly on leeward slopes, just over dune-crests, and at bases, depressions and slacks between rolling dunes. They seem rare or absent on smaller parabolic dunes, and seem excluded from more stabilized or even semi-stabilized sand-dune sites. Mature plants appear able to tolerate a considerable deposition of dry sand, since their diffuse root systems extend down to the moist and more nutrient-rich layers below.
The Mackenzie Hairgrass appears to consist of bisexual, self-incompatible, sexually outcrossing plants. Seeds apparently require a winter cold-treatment prior to their germination in spring. A long-day photoperiod seems needed for flowering induction. In the Lake Athabasca dune region, expanded panicles were noted by early to mid-July, and mature caryopses by late July to September. Numerous seeds and seedling plants have been observed in nature, and seed variability appears high. Seedling survival seems to be determined by the vagaries of the shifting sands. The species has been shown to have low genetic variability, presumably due to lack of dispersion.
Due to its low genetic variability, the species would probably adapt less readily to habitat change. It appears to be quite restricted to its specific active sand-dune habitat, and the relative lack of competition from other plants within this region. Therefore, any alteration of its habitat could represent a limiting factor for the species. Potential threats to the habitat include damage by all-terrain recreational vehicles, over-trampling by tourists, or any development in the area (e.g., mining, cottage-building) that would increase public access and the introduction of exotic weeds.
Federal ProtectionMore information about SARA, including how it protects individual species, is available in the Species at Risk Act: A Guide.
A population of the Mackenzie Hairgrass is found within Athabasca Sand Dunes Provincial Wilderness Park.
Provincial and Territorial Protection
PLEASE NOTE: Not all COSEWIC reports are currently available on the SARA Public Registry. Most of the reports not yet available are status reports for species assessed by COSEWIC prior to May 2002. Other COSEWIC reports not yet available may include those species assessed as Extinct, Data Deficient or Not at Risk. In the meantime, they are available on request from the COSEWIC Secretariat.
1 record(s) found.
- Management Plans (1 record(s) found.)
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