and economic sustainability at local and regional scales (Beniston 2012). Sensitivity
analyses of snow patterns to projected climate change may help to anticipate
conflicts; not only altitude matters for snow distribution (Uhlmann et al. 2009).
1.4 High Mountain Idiosyncratic Sensitivity
1.4.1 Temperature Versus Water
The elevation increase in mountains provides an associated decline in temperature,
atmospheric pressure and land area availability. Therefore, in a short distance environmental conditions change markedly providing the cues for a highly diverse
landscape and richness in organisms. This marked gradient also determines the high
sensitivity of mountains to climate change. The great diversity in forest formations—
and vegetation in general—is at expenses of a lower available surface for each of them
compared to plains, where similar conditions extend over large areas. Therefore,
climate change may imply a significant modification of suitable areas for a particular
type of forest, scrub or meadow (Dullinger et al. 2012).
The orographic barriers tend to increase precipitation at the slope facing the
ascending air masses. Mountains in general are, therefore, richer in water resources
than surrounding low lands and usually become a net source of water for the latter.
If air masses rich in water are mostly coming from the same direction, the vegetation contrast between mountain slopes may be remarkable. Consequently,
mountain vegetation is particularly sensitive to changes in direction and average
moisture content of air masses. In contrast to temperature, there is not a global
pattern of precipitation change with altitude (Körner 2007). In the temperate zones
of the planet, precipitation increases with elevation, either as rainfall or snow. But
in other parts of the globe the tendency can be the opposed, or the maximum can be
at intermediate levels. The mean altitude of the surrounding ranges is another factor
determining the characteristics of the altitudinal precipitation pattern. If climate
warming forces in a similar direction most of the mountains on the planet, changes
in air mass direction and moisture would show more distinctive regional (even
local) characteristics (Engler et al. 2011). Whereas long-term conservation plans
can be based on general warming projections, tendencies on precipitation would be
better assessed locally, and monitored at different sites in nature reserves with
valleys facing different directions (Beniston and Stoffel 2014).
A critical issue in areas with current positive water balance, where temperature
drives vegetation distribution, is whether changes in climate will bring to a situation
of water deficit during vegetation growth periods. The short-term and long-term
response of mountain tree populations to episodic droughts are still scarcely studied
(Cocozza et al. 2016). Nature reserves entirely or partially within this situation
would face the main challenges in the near future. Drought episodes may compensate for any fertilizing (CO 2 and N deposition increase) or warming growth
effect that may exist upon tree species usually controlled by temperature rather than
1 The High Mountain Conservation in a Changing World
17
analyses of snow patterns to projected climate change may help to anticipate
conflicts; not only altitude matters for snow distribution (Uhlmann et al. 2009).
1.4 High Mountain Idiosyncratic Sensitivity
1.4.1 Temperature Versus Water
The elevation increase in mountains provides an associated decline in temperature,
atmospheric pressure and land area availability. Therefore, in a short distance environmental conditions change markedly providing the cues for a highly diverse
landscape and richness in organisms. This marked gradient also determines the high
sensitivity of mountains to climate change. The great diversity in forest formations—
and vegetation in general—is at expenses of a lower available surface for each of them
compared to plains, where similar conditions extend over large areas. Therefore,
climate change may imply a significant modification of suitable areas for a particular
type of forest, scrub or meadow (Dullinger et al. 2012).
The orographic barriers tend to increase precipitation at the slope facing the
ascending air masses. Mountains in general are, therefore, richer in water resources
than surrounding low lands and usually become a net source of water for the latter.
If air masses rich in water are mostly coming from the same direction, the vegetation contrast between mountain slopes may be remarkable. Consequently,
mountain vegetation is particularly sensitive to changes in direction and average
moisture content of air masses. In contrast to temperature, there is not a global
pattern of precipitation change with altitude (Körner 2007). In the temperate zones
of the planet, precipitation increases with elevation, either as rainfall or snow. But
in other parts of the globe the tendency can be the opposed, or the maximum can be
at intermediate levels. The mean altitude of the surrounding ranges is another factor
determining the characteristics of the altitudinal precipitation pattern. If climate
warming forces in a similar direction most of the mountains on the planet, changes
in air mass direction and moisture would show more distinctive regional (even
local) characteristics (Engler et al. 2011). Whereas long-term conservation plans
can be based on general warming projections, tendencies on precipitation would be
better assessed locally, and monitored at different sites in nature reserves with
valleys facing different directions (Beniston and Stoffel 2014).
A critical issue in areas with current positive water balance, where temperature
drives vegetation distribution, is whether changes in climate will bring to a situation
of water deficit during vegetation growth periods. The short-term and long-term
response of mountain tree populations to episodic droughts are still scarcely studied
(Cocozza et al. 2016). Nature reserves entirely or partially within this situation
would face the main challenges in the near future. Drought episodes may compensate for any fertilizing (CO 2 and N deposition increase) or warming growth
effect that may exist upon tree species usually controlled by temperature rather than
1 The High Mountain Conservation in a Changing World
17