Feature Plant
What’s going on under the snow?
Snow covered plants in the Rocky Mountains of Alberta
Photo by L. Allen
Snow can act as an insulating blanket, keeping the plants under it warm and protecting them from frost damage. But what are the plants doing under that blanket?
Turns out, enough of the sun’s radiation can penetrate the snow that plants know the time of day, time of year, and when to initiate appropriate life phases. Even under snow depths of up to 2m, the radiation levels are strong enough to initiate sprouting and seed germination.
Korner (1999) was looking at the strategies alpine plants use to survive under snow, and divided them into six general groups.
- Some maintain green structures such as overwintering leaves or photosynthetic bark. These continue to be fully photosynthetic thru winter. Mosses and lichens can actually have a net carbon gain under the snow (depending on factors like depth and density of the snow).
- Some, like bog cranberry or lingonberry (Vaccinium vitis-idaea), retain green structures, but deactivate photosynthesis. Once snow-free, it takes about two weeks to for these plants to regain full photosynthetic capacity.
- Then there is the more conventional strategy of going dormant, with new green leaf emergence occurring after snow melt.
- But some species initiate leaf expansion while still under the snow – so they can commence greening and photosynthetic activation as soon as they are in the open. These tend to be the spring ephemerals like glacier lilies (Erythronium grandiflorum).
- Some of the fast-growing taller species like geranium actually start expansion as soon as they emerge from the snow but delay greening.
- And lastly there are the annuals, with seeds that germinate at snow melt. The longer the snow cover lasts the less well this strategy works. It is rare for an alpine plant to be an annual – takes too long to germinate, grow, flower and set seed again.
So what are the plants doing under that blanket? It seems that some are napping, some are sleeping deeply, and some are just waiting around for spring.
References: Korner, C. 1999. Alpine plant life. Functional plant ecology of high mountain ecosystems. Springer Heidelberg. 338 pp + colour plates.
Big Sagebrush Candidate Natural Area
by Adrien Corbiere
The Alberta Native Plant Council is proud to participate in the provincial Natural Areas Stewardship Program as volunteer steward for the Big Sagebrush Candidate Natural Area (BSCNA). The BSCNA is situated in the southwest corner of Alberta, lying on the east side of the South Castle River valley between Waterton Lakes National Park and the Hamlet of Beaver Mines. The area’s name comes from the presence of Big Sagebrush (Artemisia tridentata) a provincially rare plant that can be found thriving in this area. Due to it’s limited distribution in the province Big Sagebrush is ranked S2 in Alberta. All of it’s occurrences are restricted to the southwest corner of he province which forms the north-eastern border of it’s range in North America. Although considered rare in Alberta, Big Sagebrush is considered common and a weedy species in the northwestern US and parts of British Columbia.
Big Sagebrush, Alberta’s largest and most aromatic sage, is most easily identified by it’s 3 toothed leaves. In this area plants hardly reach a height higher than 3 feet but under ideal conditions the plant has been known to reach heights of up to eight feet tall.
The BSCNA is also home to over 300 other plant species including 15 rare species. Among the rare plants found here are: One-Flowered Cancer Root (Orobanche uniflora), Slender Bog Orchid (Plantanthera stricta), Large flowered Lungwort (Mertensia paniculata) and Shrubby Beardtongue (Penstemon fruticosus).
The BSCNA remains largely in a pristine undisturbed state. Human impact in the area is limited to light cattle grazing, horseback riding, hiking, and some camping and ATV use along the road that runs alongside the area. The BSCNA is still considered as a candidate natural area and thus has no special protection or management other than what is offered to all other provincially owned land. The ANPC continues to be involved in having this area accepted under the provincial Natural Area designation.