Human populations have for long displaced large carnivores populations
thought, e.g. hunting, urban development and habitat loss, being displaced to
unmanaged and protected natural environments. However, the opposite is now
happening in Europe: populations of large carnivores are increasing the occupied
territory, including places with human populations are dense with almost 100
people per square kilometre (Chapron et al. 2014; Boitani et al. 2015). Except for
the Iberian lynx, large European carnivores are making a comeback in Europe.
One-third of the European territory is now home to at least one large carnivore.
Compared to figures from the mid-twentieth century, current populations remain
stable or are on the rise. For example, Europe now boasts a population of 18,000
bears and 12,000 wolves (Naves et al. 2015; Chapron et al. 2014). The recovery of
these populations of large carnivores is partly due to the change in the social to
more positive perceptions and attitudes towards large carnivores.
The processes regulating the population and community dynamics of the large
carnivores include bottom-up forces such as primary production (soil, CO 2 and
H 2 O), nutrient dynamics (nitrogen, phosphorus, potassium and others) and energy
cycles; top-down forces such as predation, risk effects and trophic cascades;
non-predatory interactions, including facilitation and inter- and intra-specific
competition for resources; and pulse and press disturbance and perturbation events
such as fires, storms, wave action, floods and drought (Rosenblatt et al. 2013; Estes
et al. 2001). Alternative stable states occur when perturbations of sufficient magnitude and direction push ecosystems from one basin of attraction to another (Estes
et al. 2011). Trophic cascades are defined by Estes et al. (2011) and Paine (1980) as
“the propagation of impacts by consumers on their prey downward through food
webs” and by Edwards (2014) as “a series of interactions at more than one trophic
level where apex predators suppress mesopredators or prey, leading to an increase
in number and/or diversity of primary producers”.
Large predators are keystone species for the ecosystems, i.e. they are at relatively
low abundance and biomass, but have a large ecological effect on its community or
the ecosystem (Power et al. 1996; Miller et al. 2001). The disappearance or reduction
of these keystone species may lead to increases in the (now uncontrolled by top
predation) mesopredators and preys and therefore a reduction of primary resources.
10.2 The Benefits of Large Predators
What role do large carnivores play in an ecosystem? This is not an easy question to
answer. Apex predators ensure biodiversity. They are the engineers of the
ecosystem because they can change its dynamics and increase habitat heterogeneity
and biodiversity (Ritchie et al. 2012). They prevent the spread of diseases and
invasive species. They also maintain the physical and chemical conditions of the
soil and water (Estes et al. 2011). They can connect different, often distant, habitats
and their behaviour affects biogeochemical and nutrient dynamics. How do large
carnivores affect ecosystems? Mainly in two ways: through prey control and
10 The Importance of Reintroducing Large Carnivores …
233
thought, e.g. hunting, urban development and habitat loss, being displaced to
unmanaged and protected natural environments. However, the opposite is now
happening in Europe: populations of large carnivores are increasing the occupied
territory, including places with human populations are dense with almost 100
people per square kilometre (Chapron et al. 2014; Boitani et al. 2015). Except for
the Iberian lynx, large European carnivores are making a comeback in Europe.
One-third of the European territory is now home to at least one large carnivore.
Compared to figures from the mid-twentieth century, current populations remain
stable or are on the rise. For example, Europe now boasts a population of 18,000
bears and 12,000 wolves (Naves et al. 2015; Chapron et al. 2014). The recovery of
these populations of large carnivores is partly due to the change in the social to
more positive perceptions and attitudes towards large carnivores.
The processes regulating the population and community dynamics of the large
carnivores include bottom-up forces such as primary production (soil, CO 2 and
H 2 O), nutrient dynamics (nitrogen, phosphorus, potassium and others) and energy
cycles; top-down forces such as predation, risk effects and trophic cascades;
non-predatory interactions, including facilitation and inter- and intra-specific
competition for resources; and pulse and press disturbance and perturbation events
such as fires, storms, wave action, floods and drought (Rosenblatt et al. 2013; Estes
et al. 2001). Alternative stable states occur when perturbations of sufficient magnitude and direction push ecosystems from one basin of attraction to another (Estes
et al. 2011). Trophic cascades are defined by Estes et al. (2011) and Paine (1980) as
“the propagation of impacts by consumers on their prey downward through food
webs” and by Edwards (2014) as “a series of interactions at more than one trophic
level where apex predators suppress mesopredators or prey, leading to an increase
in number and/or diversity of primary producers”.
Large predators are keystone species for the ecosystems, i.e. they are at relatively
low abundance and biomass, but have a large ecological effect on its community or
the ecosystem (Power et al. 1996; Miller et al. 2001). The disappearance or reduction
of these keystone species may lead to increases in the (now uncontrolled by top
predation) mesopredators and preys and therefore a reduction of primary resources.
10.2 The Benefits of Large Predators
What role do large carnivores play in an ecosystem? This is not an easy question to
answer. Apex predators ensure biodiversity. They are the engineers of the
ecosystem because they can change its dynamics and increase habitat heterogeneity
and biodiversity (Ritchie et al. 2012). They prevent the spread of diseases and
invasive species. They also maintain the physical and chemical conditions of the
soil and water (Estes et al. 2011). They can connect different, often distant, habitats
and their behaviour affects biogeochemical and nutrient dynamics. How do large
carnivores affect ecosystems? Mainly in two ways: through prey control and
10 The Importance of Reintroducing Large Carnivores …
233