Environmental Engineering Reference
In-Depth Information
most important of these changes in the context of the Mediterranean mountains are
discussed below.
10.2.1 Climate change
Although palaeoecological evidence for climate change exists for the Mediter-
ranean, the sites are located in the lowlands, making extrapolation to mountains
difficult. However, climate change is currently considered the driving force in
ecosystem change during glacial-interglacial cycles (see Chapter 2). For the
Mediterranean, models forecast significant increases in temperature and decreases
in rainfall during the twenty-first century. These changes coupled with land use
changes lead towards an uncertain future for the mountains of the Basin, as
discussed in Chapter 9. Due to their close relationship with climate (especially
temperature and precipitation), glaciers are the system most sensitive to climate
change. Thus, the glacial record of the Mediterranean mountains has the potential
to provide perhaps the clearest signal about past and future climate changes. How-
ever, as Hughes points out (see Chapter 3) there are still gaps in our knowledge of
glacial geochronology in many mountains in the Mediterranean.
The amount and duration of rainfall in addition to the length of intervals be-
tween rainfall events are three import aspects of climate, the variation of which will
influence geomorphological processes in mountain environments. Combined with
changes in temperature these will result in changes in soil properties and acceler-
ate desertification particularly in areas that border semi-arid areas (Geeson
et al.,
2002). An increase in the frequency of extreme events has been suggested as a di-
rect result of climate change, manifesting itself as droughts and sediment transfer,
and there is already evidence of that in Mediterranean mountain areas (Maas and
Macklin, 2002).
There is evidence worldwide that climate change has already resulted in shifts
in species ranges, timing of seasonal events and habitat preferences (Lenoir
et al.,
2008; Gottfried
et al.,
2012). In a mountain setting the effect on glaciers, snow
regime and water regime will in turn have an impact on associated habitats and
species. The possible reduction of habitat availability in the alpine and subalpine
zone/belts increases the risk of extinction for endemic species or range-restricted
species. The increase in frequency and intensity of fire outbreaks has been already
reported from the Mediterranean areas (Mouillot
et al.,
2002; Pausas, 2004), and
in the case of the Mediterranean mountains this is already occurring, as demon-
strated by the large-scale fires in the mountains of the Peloponnese, south Greece,
in August 2007. With the help of forest gap dynamics, in a case study in north-
eastern Mediterranean mountain forests, Fyllas and Troumbis (2009) showed that
fire events should increase in number and will be associated with elevational shifts
of the dominant tree species. Studies that have addressed the community-level re-
sponses to climate change in Mediterranean mountain ranges indicate that there
