Shrub Line Advance in Alpine Tundra of the Kluane Region: Mechanisms of Expansion and Ecosystem Impact
Myers-Smith, I. 2007.
Abstract
With a warming climate, northern ecosystems
will face significant ecological changes such as
permafrost thaw, increased forest fire frequency,
and shifting ecosystem boundaries, including the spread of
tall shrubs into tundra. In northern mountain ranges such
as those in the southwestern Yukon, the shrub line will
likely advance up mountain slopes with climate warming
(Danby and Hik, 2007). This loss of alpine tundra will
decrease the success of obligate tundra species such as
hoary marmot (Marmota caligata), collared pika (Ochotona
collaris), and ptarmigan (Lagopus sp.) (Martin, 2001).
Vegetation changes in northern ecosystems are also likely
to affect foraging mammals and birds (Hinzman et al.,
2005). For example, increases in the biomass of woody
shrub species such as willow may reduce habitat for
caribou (Sturm et al., 2005a) while benefiting moose
(Kelsall, 1972). In addition to modifying wildlife habitat,
increased shrub height and density will make traversing
tundra more difficult, a problem for hikers and hunters.
