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- Give one frequently and one rarely occurring type of disturbance in
the alpine environment. What are the causes of these disturbances? To
what extent are they influenced by other types of disturbance?
Answer: Frequently occurring: e.g. freeze-thaw
- caused by temperature fluctuations around the freezing point in combination
with water saturated soils; Bare substrate created by diverse disturbances
is susceptible to freeze-thaw, disturbances which lead to dry soil may
impede needle-ice formation and therefore the effects of freeze-thaw.
Rarely occurring: e.g. glacier - caused by consolidated
ice which creeps downslope and erodes the land surface and scours the
bedrock; Glaciers are not obviously affected by other types of disturbance.
- List at least three possible effects of disturbance on alpine vegetation.
Answer: Many disturbances destroy the vegetation
to some extent.
Gap creation may increase species diversity.
Frequent disturbance may impede vegetation development or vegetation
may be replaced by a specially adapted vegetation.
- Give one direct disturbance caused by human activities in the alpine
environment and at least one possible indirect effect of global change
on the "natural" disturbance regime of the alpine environment.
Why is the alpine environment highly susceptible to human impact?
Answer: Disturbance directly caused by humans: e.g.
trampling of the vegetation by hikers.
An indirect effect of global warming may be a more dynamic precipitation
regime going along with an increase in the frequency and intensity of
storms. An increase in the frequency and size of rainstorms would trigger
the release of mudflows and debris flows.
Slow plant growth and slow soil formation make the alpine environment
highly vulnerable to human impact.
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