(Galiano et al. 2010). Stand density also appears to be a contributing factor since
competition for scarce water is to be expected. Moreover, bark beetle proliferation,
a common driver of conifer mortality in association with drought, has been detected
in damaged Scots pine stands in the Alps (Dobbertin et al. 2007) and it is one of the
main causes of forest dieback in Western North America (Hart et al. 2014).
A parallel die-off is occurring in silver fir forest in the Pyrenees, associated with
logging in the past (Camarero et al. 2011; Camarero 2017a). The primary or
contributing role of pests and pathogens versus drought is also often hard to elucidate, as they can establish mutually reinforcing feedback (Hart et al. 2014; Oliva
et al. 2014). Such multiple interactions between factors that contribute to the decline
of forests are common in many mountain areas of the world and must be taken into
account by conservation managers in the new climatic scenarios (Allen et al. 2015).
2.5 Managing Conflicting Goals
The allocation of resources to competing goals represents a clear example of the
application of trade-offs to conservation issues. The paradigmatic case involves
the economic benefits obtained from the harvesting of natural resources, which in
the mountains usually correspond to timber, grass and fish, versus values associated
with biodiversity, often exemplified by key or charismatic species, by species
diversity or by ecosystem functioning. This approach, which can be spatially and
temporally explicit, makes it possible to develop cost-effective models that optimise
the outcome of different goals subject to trade-offs, after combining functions that
share a common currency (e.g. economic value). These models have, for instance,
been widely used to assess wildlife and timber production in mountain forest
regions (Nalle et al. 2004) (Fig. 2.3b), and to assess the relationship between forage
production and the abundance of particular plant species that denote environmental
quality in mountain grasslands (Loucougaray et al. 2015). Another case is the
trade-off between the financial income produced by the introduction of non-native
fish to lakes and streams and the environmental costs (Ventura et al. 2017); in this
case, the focal entity corresponds to the whole watershed ecosystem. These
cost-effective models also allow us to simulate outcomes by applying alternative
management actions at different times—i.e. spreading the investment of resources
over time (Lampert et al. 2014). Nevertheless, one major challenge for such
quantitative analyses is the parameterisation of the current common currency for the
various alternative management actions.
Although functions subject to trade-off show a negative relationship of their
estimators, not all negative correlations are the result of resource allocation for the
overall maintenance of a system. Recent changes in land use in European mountain
areas (Pèlachs et al. 2017), provide an interesting case for illustrating the complexity of this approach. In these areas, the human-induced transformation of the
landscape has led to the loss of most woodland while agricultural and grazing areas
have increased. Since the mid-twentieth century, however, significant depopulation
48
F. Lloret
competition for scarce water is to be expected. Moreover, bark beetle proliferation,
a common driver of conifer mortality in association with drought, has been detected
in damaged Scots pine stands in the Alps (Dobbertin et al. 2007) and it is one of the
main causes of forest dieback in Western North America (Hart et al. 2014).
A parallel die-off is occurring in silver fir forest in the Pyrenees, associated with
logging in the past (Camarero et al. 2011; Camarero 2017a). The primary or
contributing role of pests and pathogens versus drought is also often hard to elucidate, as they can establish mutually reinforcing feedback (Hart et al. 2014; Oliva
et al. 2014). Such multiple interactions between factors that contribute to the decline
of forests are common in many mountain areas of the world and must be taken into
account by conservation managers in the new climatic scenarios (Allen et al. 2015).
2.5 Managing Conflicting Goals
The allocation of resources to competing goals represents a clear example of the
application of trade-offs to conservation issues. The paradigmatic case involves
the economic benefits obtained from the harvesting of natural resources, which in
the mountains usually correspond to timber, grass and fish, versus values associated
with biodiversity, often exemplified by key or charismatic species, by species
diversity or by ecosystem functioning. This approach, which can be spatially and
temporally explicit, makes it possible to develop cost-effective models that optimise
the outcome of different goals subject to trade-offs, after combining functions that
share a common currency (e.g. economic value). These models have, for instance,
been widely used to assess wildlife and timber production in mountain forest
regions (Nalle et al. 2004) (Fig. 2.3b), and to assess the relationship between forage
production and the abundance of particular plant species that denote environmental
quality in mountain grasslands (Loucougaray et al. 2015). Another case is the
trade-off between the financial income produced by the introduction of non-native
fish to lakes and streams and the environmental costs (Ventura et al. 2017); in this
case, the focal entity corresponds to the whole watershed ecosystem. These
cost-effective models also allow us to simulate outcomes by applying alternative
management actions at different times—i.e. spreading the investment of resources
over time (Lampert et al. 2014). Nevertheless, one major challenge for such
quantitative analyses is the parameterisation of the current common currency for the
various alternative management actions.
Although functions subject to trade-off show a negative relationship of their
estimators, not all negative correlations are the result of resource allocation for the
overall maintenance of a system. Recent changes in land use in European mountain
areas (Pèlachs et al. 2017), provide an interesting case for illustrating the complexity of this approach. In these areas, the human-induced transformation of the
landscape has led to the loss of most woodland while agricultural and grazing areas
have increased. Since the mid-twentieth century, however, significant depopulation
48
F. Lloret