mountains are experiencing a large cultural and socio-economical shift in many
regions of the world (Ooi et al. 2015). Transport facilities have increased visitors,
and tourism has become a significant economic element in the high mountain and
around nature reserves (Oian 2013). In parallel, most traditional land uses—once
diversified and recurrent—are vanishing as local pressures on mountain ecosystems.
Mountain conservation involves a daunting task evaluating exposure and sensitivity
to a wealth of exceptionally dynamic pressures. An accurate evaluation is fundamental for defining new conservation goals since a crude estimation indicates that
traditional ones may not be possible any longer.
1.2 Mountain Exposure to Global Changes
1.2.1 Climate Change
It has been suggested that mountains experience stronger cold and warm climatic
fluctuations than average lands (Dedieu et al. 2014; Beniston 2006). Despite this
may be a matter of debate, there is no question that the recording and perception of
warming during the last decades have been observed at many different ranges (Diaz
and Bradley 1997). The particularity with mountains is that the altitudinal gradient
induces contrasting climates in a short distance. With climate change, the regional
means will change, but the altitudinal and other topographically-induced variability
may also be modified. All in all, mountains will warm throughout the world
(Nogues-Bravo et al. 2007).
In regions with relatively dry average climates, such as the Mediterranean,
high-mountains constitute sources of water to lowlands (Boithias et al. 2014).
Ascending from plains, one goes across water-driven vegetation to mostly
temperature-driven ecosystems. Not only in these mountain ranges but in general,
the way in which precipitation will regionally shift appears critical to project
potential vegetation changes, including details of the topographical climatic variation in the high-mountain (McCullough et al. 2016). The Mid-Holocene has
provided clear evidence that a complete shift in dominant landscape vegetation is
possible at sub-millennial time scales (Carrion 2002), with transitional changes at
local scales probably occurring over decadal periods. Mountain nature reserves may
be submitted to progressive declines in annual precipitation and also to increasing
frequency of drought events (Beniston et al. 2007). The character of the shift, either
smooth or abrupt, may result in entirely different interactions with other processes,
such as pests (Hodar et al. 2003), invasive species (Thomas 2010), pollution
(Bogdal et al. 2010), etc.
Even in ranges not expected to experience changes in annual precipitation,
warming will change the hydric balance. The seasonal pattern of warming would
play a critical role in determining the kind of new situations that ecosystem
experience. For instance, summer and autumn warming may lead to seasonal water
6
J. Catalan et al.
regions of the world (Ooi et al. 2015). Transport facilities have increased visitors,
and tourism has become a significant economic element in the high mountain and
around nature reserves (Oian 2013). In parallel, most traditional land uses—once
diversified and recurrent—are vanishing as local pressures on mountain ecosystems.
Mountain conservation involves a daunting task evaluating exposure and sensitivity
to a wealth of exceptionally dynamic pressures. An accurate evaluation is fundamental for defining new conservation goals since a crude estimation indicates that
traditional ones may not be possible any longer.
1.2 Mountain Exposure to Global Changes
1.2.1 Climate Change
It has been suggested that mountains experience stronger cold and warm climatic
fluctuations than average lands (Dedieu et al. 2014; Beniston 2006). Despite this
may be a matter of debate, there is no question that the recording and perception of
warming during the last decades have been observed at many different ranges (Diaz
and Bradley 1997). The particularity with mountains is that the altitudinal gradient
induces contrasting climates in a short distance. With climate change, the regional
means will change, but the altitudinal and other topographically-induced variability
may also be modified. All in all, mountains will warm throughout the world
(Nogues-Bravo et al. 2007).
In regions with relatively dry average climates, such as the Mediterranean,
high-mountains constitute sources of water to lowlands (Boithias et al. 2014).
Ascending from plains, one goes across water-driven vegetation to mostly
temperature-driven ecosystems. Not only in these mountain ranges but in general,
the way in which precipitation will regionally shift appears critical to project
potential vegetation changes, including details of the topographical climatic variation in the high-mountain (McCullough et al. 2016). The Mid-Holocene has
provided clear evidence that a complete shift in dominant landscape vegetation is
possible at sub-millennial time scales (Carrion 2002), with transitional changes at
local scales probably occurring over decadal periods. Mountain nature reserves may
be submitted to progressive declines in annual precipitation and also to increasing
frequency of drought events (Beniston et al. 2007). The character of the shift, either
smooth or abrupt, may result in entirely different interactions with other processes,
such as pests (Hodar et al. 2003), invasive species (Thomas 2010), pollution
(Bogdal et al. 2010), etc.
Even in ranges not expected to experience changes in annual precipitation,
warming will change the hydric balance. The seasonal pattern of warming would
play a critical role in determining the kind of new situations that ecosystem
experience. For instance, summer and autumn warming may lead to seasonal water
6
J. Catalan et al.