north america cold biomes david leblanc ed white
TRANSCRIPT
North America Cold Biomes
David LeBlancEd White
Arctic Tundra
David LeBlanc
Gates of the Arctic National Park, Brooks Range, Alaska.
Dominant plants are low-lying shrubs, grasses, and forbs with scattered stunted trees.www.bsu.edu/biology/leblanc
Anuktuvuk Pass, Brooks Range, Alaska.
Further north no trees at all, just low-lying shrubs, grasses and forbs.68o 03’ 42.98” N, 151o 58’ 12.81” W
Note: This is an example of an image that displays characteristics of dominant plant species.
Note: This is an example of an image that displays landscape scale characteristics.
Arctic Tundra: Climate
Short, cool frost-free growing season limits Pnet and growth of trees.
Extreme, cold winters. Low-lying shrubs, grasses,
forbs dominate b/c they are protected under snow during winter.
Trees not present b/c little or no growing season to produce wood and they cannot survive harsh winter conditions.
Climate Change:Warmer Only
Increased Temperature but w/ same Precipitation
Winters would be less severe, BUT entire growing season would be too dry to support plant growth
Vegetation becomes Cold Desert.
Climate Change: Warmer & Wetter
Increased Temperature AND Precipitation
Winters less severe Growing season warmer &
longer but precipitation adequate only at beginning and end, droughts in some years.
w/ short growing season vegetation remains tundra or becomes sparse, stunted boreal forest.
Boreal Forest
Ed White
Banff National Park, Alberta, Canada.
Dominant plants are evergreen trees.www.bsu.edu/biology/leblanc
Chutes-des-Passes, Lac St. John, Quebec.
Boreal forest dominated by evergreen trees (spruce and fir).49o 50’ 49.70” N, 71o 11’ 42.39” W
Boreal Forest Climate
Short, cool frost-free growing season limits Pnet
Long, cold winters. No dry months; fire unlikely. Evergreen conifer trees able to
extend growing season by photosynthesizing on warm days in Spring and Fall.
Evergreen conifer foliage better able to retain heat during cool growing season, increasing Pnet..
Climate Change:Warmer Only
Increased Temperature but w/ same Precipitation
Winters would be less severe and frost-free growing season longer.
Precipitation probably adequate to support growth during growing season, but droughts and fire may become more frequent
Vegetation may shift to Temperate Deciduous Forest
Climate Change:Warmer & Wetter
Increased Temperature AND Precipitation
Winters less severe Growing season warmer and
longer with much precipitation and no droughts.
Vegetation becomes Temperate Deciduous Forest.
Climate Change Summary
In tundra, cold temperature becomes less limiting, but drought stress increases; vegetation shifts from cold-limited to drought-limited cold desert.
In boreal forest, cold temperature becomes less limiting and growing season expands. W/ adequate water availability vegetation will shift from evergreen trees to temperate deciduous trees.