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Biophysical Descriptions – Whitehorse Trough

Whitehorse Trough Ecozones and Ecoregions
The Whitehorse Trough Ecozone is found entirely within the Boreal Cordillera Ecozone. This area consists of the Yukon Plateau - Central, Yukon Southern, Yukon Stikine Highlands and the Boreal Mountains and Plateau ecoregions.

  • Boreal Cordillera Ecozone  4.3 MB
    The Boreal Cordillera Ecozone is an extension of the boreal forest zone that spans across the continent from the Atlantic coast. It is modified within the Cordillera by strong gradients of elevation, temperature and precipitation over short distances. Most of the ecozone experiences a rapid increase in stream flow discharge in May due to snowmelt, with high flow continuing for a few weeks maintained by summer rainfall. Because it is south of the continuous permafrost zone, there is more ground water flow than in the Taiga Cordillera Ecozone and ground water discharge generally continues throughout winter. The Pacific maritime influence moderates temperatures over most of the ecozone.
    • Yukon Plateau – Central Ecoregion  566 KB
      The western portions of the Yukon Plateau-Central ecoregion are very dry with annual precipitation amounts of only 250 to 275 millimetres. The south-facing slopes support extensive grassland communities and wetlands associated with the Tintina Trench flyway, such as Reid Lakes and the Needle Rock complex, provide important migratory and nesting habitat for waterfowl. Very frequent forest fires maintain vast areas of relatively young aspen and lodgepole pine forests.
    • Yukon Southern Lakes Ecoregion  556 KB
      Broad valleys and large lakes characterize the Yukon Southern Lakes Ecoregion. Set within the rain shadow of the St. Elias Mountains, this area has a dry and cool climate. It lies in a sporadic discontinuous permafrost zone, where permafrost underlies less than one quarter of the landscape. Soils tend to be alkaline and wetlands (mainly fens) are typically dominated by marl formation. This ecoregion supports the highest mammalian diversity in the Yukon, with representatives of at least 50 of the 60 species known to occur at present.
    • Yukon Stikine Highlands Ecoregion  354 KB
      The Yukon Stikine Highlands Ecoregion is heavily influenced by Pacific maritime weather systems, producing relatively moderate temperatures and enough precipitation to support scattered alpine glaciers. Forest vegetation does not experience the temperature and moisture stresses common elsewhere in southwestern Yukon. Adapted to steep terrain and high snowfall, mountain goats reach their highest Yukon population densities here.
    • Boreal Mountains and Plateau Ecoregion  263 KB
      The Boreal Mountains and Plateaus Ecoregion, centred in northern British Columbia, extends into only two small areas in southern Yukon. In these, the landscape and biota differ little from the highlands of the neighbouring Yukon Southern Lakes Ecoregion. Wetlands and subalpine forest support a diverse bird population, particularly during spring and fall.

Source: Smith, C.A.S., Meikle, J.C. and Roots,C.F. (editors), 2004. Ecoregions of the Yukon Territory - Biophysical Properties of Yukon Landscapes. Agriculture and Agri-Food Canada, PARC Technical Bulletin 04-01, Summerland, British Columbia, pages 187 to 240.