Get Outdoors!: snow foundation of temporary ecosystem

Get Outdoors!: snow foundation of temporary ecosystem

An under-the-snow oasis is home to all kinds of creatures and plants

A whole new temporary ecosystem develops here every winter wherever snow piles deeply enough to cover plants.

It’s the subnivean (under snow) environment.

Silver Star Mountain’s subalpine environment (includes Sovereign Ski and snowmobile area) and the tops of our valley’s surrounding high hills and mountains re-establish subnivean environments every November to April, and sometimes longer.

Silver Star’s snow is usually two to three metres deep by January.

As snow falls and settles, it bends over grasses, shrubs and even young trees and piles up on top creating a tunnelled network on the ground.

The earth is always giving off enough warmth to keep the ground air temperature above freezing.

Mice and other small mammals live under this downy quilt of snow in the subnivean environment that shelters them from the cold above.

The critters subsist on seeds, lichens, fungi and plants.

Hawks can’t find the mice, so they migrate, but owls stay and listen.

They can hear mice under half a metre of snow and dive down talons first to catch their prey.

Coyotes catch the scent of subnivean rodents. With a fierce pounce they dive into the snow muzzle first.

Snow weasels/ermine enter the subnivean network through holes beside shrubs and tree trunks to catch rodents.

Spruce Grouse and Ptarmigans will dive into subnivean air pockets to keep warm.

By mid-February, the CO2 levels get high in these passageways and pockets, the little critters come out more often for a breath of fresh air.

Wouldn’t you know it — that’s just when male owls get busy supplying their ladies with food and furs.

Black bears cozily hibernate under snow-covered fallen logs or against tree trunks with large, limber snow-covered branches that eventually close off the den once snow piles up.

Snowshoeing is a marvellous way to encounter this wild winter wonderland.

Next time you’re out snowshoeing, see if you can identify the wildlife tracks.

Look for subnivean world entry holes beside tree trunks or near bent over, snow-covered shrubs which look like bumps on the undulating snowy landscape.

And realize there’s a whole busy community thriving under your trail.

If it’s warm enough, sit still for a few minutes.

You may be lucky enough to catch some subnivean comings and goings.

Roseanne Van Ee shares her vast knowledge of the outdoors to help readers experience and enjoy nature.