Research Branch


See below to download Brochure 83 PDF file.
   

The ecology of the alpine zones

Author(s) or contact(s): Research Branch
Source: Research Branch
Subject: Ecology
Series: Brochure
Other details:  Published 2006. Hardcopy is available.
 

Abstract

This brochure replaces the Alpine Tundra Zone brochure.

The alpine occurs at high elevations throughout British Columbia and has the harshest climate of any of the biogeoclimatic zones in British Columbia. Temperatures are cold for most of the year, with much wind and snow. Temperatures remain low even during the growing season, which has an exceptionally short frost-free period. Mean annual temperatures range from 0 to 4C, and the average monthly temperature stays below 0C from 7 to 11 months of the year. The mean temperature of the warmest month is less than 10C. A great deal of precipitation falls in this zone, mostly as snow.

This region is separated into three alpine zones with different climate and vegetation.

The Coastal Mountain-heather Alpine Zone (CMA) occurs along the windward spine of the Coast Mountains and the mountains of Vancouver Island and the Queen Charlotte islands where the snowpack is deep and summers are moderated by maritime influences. The treeline in this environment is lowered by heavy and prolonged snow cover and can be as much as 900 m lower than in the alpine of comparable latitudes in the dry interior. Alpine begins at 1600 m in the south, descending to 1000 m in the north. Though this zone is extensive, the most of the land area is occupied by glaciers or recently exposed bare rock at the elevation of true alpine.

The Interior Mountain-heather Alpine Zone (IMA) occupies the entire Columbia Mountains, the southern Rocky Mountains, and the lee side of the Coast and
Cascade Mountains. The Interior Mountain-heather Alpine Zone is the smallest of the alpine zones since the altitude at which it begins is above the height of most of the mountain ranges: 2500 m in the dry south to 1800 m in the north. There is much precipitation variation within the zone but summers are warm relative to the other alpine zones.

The Boreal Altai Fescue Alpine Zone (BAFA) is the most extensive of the alpine zones, occupying the northern Rocky, Skeena, Omineca, and Cassiar Mountains in the north and the lee side of the Coast Mountains as far south as the Chilcotin. Winters are very cold and long, and summers are brief and cool but with very long day length. A thin windblown snowpack is typical of the Boreal Altai Fescue Alpine Zone but deeper snowpacks occur in some areas. Ground freezing and cryoturbation (frost churning) features are common. Much of the Boreal Altai Fescue Alpine Zone is well-vegetated alpine tundra.

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Updated October 17, 2008