Preserving species preserves functions, with the added value that no judgments are
required on which functions have to be prioritized. On the other hand, partial
functional redundancy is a fact in nature. Probably simply by natural selection,
essential functions have become more redundant than the ones less critical for the
organization of ecosystem functioning regarding cycling of matter and energy flow.
1.5.4 Size Matters
It is unclear how much of the present distribution of species in high mountains is
related to human influence. Treeline has been modified at least since about
3000 years ago in many European mountain valleys (Pèlachs et al. 2017). Fire was
the tool to open the landscape (Tinner et al. 2005). The artificial maintenance of
pasturing meadows at high altitude should have modified the species assemblage
and favored some of them, according to the enhanced grazing and fertilization. It
would be interesting to check whether a selection of species or morphotypes can be
related to these increased pressures. Similarly, the human pressure on some trees
may not have been genetically innocuous. Fir (Abies alba) is currently mostly
restricted to north-facing slopes in the Pyrenean valleys. However, there is growing
evidence that in the past, along the second half of the Holocene, it also extended
through south-facing slopes over a larger area. Apparently, there are not climatic
reasons for the observed change. Rather, there is growing palaeoecological evidence that humans have preferred to leave fir in the shaded areas and facilitate other
species (e.g., pines (Pinus sylvestris, P. uncinata), or beech (Fagus sylvatica),
among others) in the sunny slopes and plains. This practice may have lasted during
centuries, perhaps actually introducing a shift towards these conditions in the
Pyrenean fir metapopulation. Studies across the range of Abies alba indicate an
intense human pressure on this tree in Southern Europe (Ruosch et al. 2016). In any
case, with decreased forestry activity within and outside the nature reserves, current
tree distribution in many mountains would be changing even without climate
change. Many nature reserves may be too small to cope appropriately with these
changes and forest mass conservation in general. Reserve size matters, at least
concerning trees and large mammals, thus conservation policy outside natural
reserves becomes a vital element for them. Natural reserves may provide space for
pilot studies and observations to inform decisions over large mountain-areas
regulation.
1.5.5 Local Contribution to Global Ecological Services
The task that mountain nature reserves may play in mitigating global change may
appear as insignificant. Although carbon stock in soils and forests may be high per
surface unit (Garcia-Pausas et al. 2017), the overall figure may become irrelevant
26
J. Catalan et al.
required on which functions have to be prioritized. On the other hand, partial
functional redundancy is a fact in nature. Probably simply by natural selection,
essential functions have become more redundant than the ones less critical for the
organization of ecosystem functioning regarding cycling of matter and energy flow.
1.5.4 Size Matters
It is unclear how much of the present distribution of species in high mountains is
related to human influence. Treeline has been modified at least since about
3000 years ago in many European mountain valleys (Pèlachs et al. 2017). Fire was
the tool to open the landscape (Tinner et al. 2005). The artificial maintenance of
pasturing meadows at high altitude should have modified the species assemblage
and favored some of them, according to the enhanced grazing and fertilization. It
would be interesting to check whether a selection of species or morphotypes can be
related to these increased pressures. Similarly, the human pressure on some trees
may not have been genetically innocuous. Fir (Abies alba) is currently mostly
restricted to north-facing slopes in the Pyrenean valleys. However, there is growing
evidence that in the past, along the second half of the Holocene, it also extended
through south-facing slopes over a larger area. Apparently, there are not climatic
reasons for the observed change. Rather, there is growing palaeoecological evidence that humans have preferred to leave fir in the shaded areas and facilitate other
species (e.g., pines (Pinus sylvestris, P. uncinata), or beech (Fagus sylvatica),
among others) in the sunny slopes and plains. This practice may have lasted during
centuries, perhaps actually introducing a shift towards these conditions in the
Pyrenean fir metapopulation. Studies across the range of Abies alba indicate an
intense human pressure on this tree in Southern Europe (Ruosch et al. 2016). In any
case, with decreased forestry activity within and outside the nature reserves, current
tree distribution in many mountains would be changing even without climate
change. Many nature reserves may be too small to cope appropriately with these
changes and forest mass conservation in general. Reserve size matters, at least
concerning trees and large mammals, thus conservation policy outside natural
reserves becomes a vital element for them. Natural reserves may provide space for
pilot studies and observations to inform decisions over large mountain-areas
regulation.
1.5.5 Local Contribution to Global Ecological Services
The task that mountain nature reserves may play in mitigating global change may
appear as insignificant. Although carbon stock in soils and forests may be high per
surface unit (Garcia-Pausas et al. 2017), the overall figure may become irrelevant
26
J. Catalan et al.