Global Change and Mountains: Consequences, Responses and Opportunities - Impact of Global Changes on Mountains: Responses and Adaptation - page 99

(Stern et al. 2006). However, in view of the complexity of inter-linkages
between the climatic and non-climatic drivers infl uencing the mountain
freshwater resources and very high improbability regarding changes in
precipitation patterns it is extremely diffi cult to project future changes in
mountain freshwater ecosystems.
In the Andes, clean water becomes a critical resource for future sustain-
able development, taking into consideration the generalized scarcity of
resources in the country. Climate change has already decreased the annual
average rainfall by 50% in the southernmost section of Chilean Patagonia,
mean and minimum temperatures are increasing, snowlines are rising
and glaciers are retreating (CONDESAN 2011). There are already serious
concerns about decreasing availability of freshwater and reduced supply
of hydropower in cities, such as La Paz, Lima and Quito (CONDESAN
2011). The glacier runoff is highly signifi cant for the supply of freshwater
in Peru and Bolivia (Buytaert et al. 2011) where the decreasing glacier
runoff is affecting the prime agricultural areas in many of the Andean
valleys, particularly in Cordillera Norte and in Central Argentina and
Chile (CONDESAN 2011). Decreases in water levels in rivers originating
in mountains in the provinces of Río Negro and Neuquén, probably due
to reductions in snowfall in the Andes, have already led to 40% reductions
in hydroelectricity generation (República de Argentina 2007) (Table 4.5).
Mountain ecosystems sustain about 50% of the global biodiversity,
and support approximately half of the biodiversity hotspots of the planet
(Hassan et al. 2005). Furthermore, nearly 28% of the geographical area of
the world's terrestrial protected areas has their home in the mountains
(Kollmair et al. 2005). Nonetheless, mountain biological species are adapted
to specifi c altitudinal zones and microclimatic conditions; hence they are
highly sensitive to climate variability (Hassan et al. 2005, IPCC 2007a,b).
The high altitude, steep terrain, the compression of climatic zones, and
landscape fragmentation, increases the biological richness in terms of
both species diversity and endemism in mountain ecosystems (IPCC
2007a,b, Körner 2009). The observed trends of changes in temperature are
expected to push the vegetation belts upward in higher elevations and the
geographical ranges of species may advance northward in the northern
hemisphere changing the species composition of communities (Nogues-
Bravo et al. 2007, Singh et al. 2010). The advancing unfolding, blossoming,
and ripening in the leaves and fruit of wild plants; and of hibernation,
migration, and breeding of wildlife have been observed in mountain regions
(ICIMOD 2007). In China, the phenology of events has become two to four
days earlier than observed in 1980s (Zheng et al. 2002). The climate change
also increases the risk of extinction for species with narrow geographic or
climatic distributions and also disruption of existing communities. A large
number of endemic plant species are unable to respond appropriately to