Climate Change and the Rocky Mountains - Impact of Global Changes on Mountains: Responses and Adaptation - page 439

one stressor, the blister rust, now must contend with several other stressors
that directly or indirectly result from climate change.
Snow-dependent wildlife vulnerabilities
Over millennia many wildlife species have adapted to snow regimes in the
Rocky Mountains to improve their survival, reproduction and persistence.
As snowpacks diminish in depth and extent, melt earlier in the spring, and
change thermal characteristics as they become warmer, these fi ne-tuned
characteristics may lose their advantages or even become maladaptive.
The snowshoe hare (Lepus americanus), for instance, rapidly molts to
change the color of its fur to white as winter approaches. While effective
against a snow background, it serves to attract predators against a snowless
forest background, indicating that timing this pelage change to patterns of
snowfall is critical. Pederson et al. (2010) documented that snowmelt has
shifted two weeks earlier in western Montana. Mills et al. (2013) recorded
numerous instances of snowshoe hares remaining partially white in early
spring well after snow had melted. If the pelage change is triggered by day-
length changes, as many biological phenomena are, then climate change-
driven speeding of spring snowmelt will result in a long-term seasonal
mismatch for this organism and mismatched hares die at higher rates
(Mills et al. 2013). Projected reductions in average duration of snowpack
suggest that there will be an additional 40-69 snowless days by the end of
the century and hares will be mismatched four to eight times more often.
A major predator of the snowshoe hare is the lynx (Lynx canadensis),
so hare population declines are expected to adversely affect lynx. Lynx also
share the adaptation to snow of having extra-large feet to provide support
when moving across snow, which provides a competitive edge for the lynx
over other medium-sized carnivores such as coyotes (Canis latrans). With
a less snow-dominated environment becoming a new reality in much of
the Rocky Mountains, wildlife managers have to consider whether the loss
of the lynx's competitive advantage will result in their population decline.
Signifi cant resources have gone into establishing lynx in many areas of
its current core habitat but the degree to which they can adapt to climate
change is speculative.
Landscape Scale Disturbance
Many climate change effects are direct, such as the facilitation of seedling
establishment due to reduced snowpack persistence, whereas other effects
are indirect. Perhaps the most transformative indirect effect is climate
change's role in altering disturbance processes such as wildland fi re and