220
Prosopis nigra, while Prosopis chilensis and Prosopis flexuosa appear in the arid
Chaco (Galera 2000). However (see Chap. 9), genetic, taxonomic, and ecophysiological studies identify important differences between populations of P. alba distributed in the semi-arid and humid Chaco (Verga et al. 2009; Verga 2014). On the other
hand, a fifth species of algarrobo stands out in the north of the humid Chaco subregion: Prosopis hassleri. In Argentina it occupies only a strip of no more than 50 km
wide south of the Pilcomayo River (which forms the border with Paraguay), ranging
from the Paraguay River to the limit with the semi-arid Chaco. This is the southern
end of the distribution area of this species, whose center is located in the Paraguayan
humid Chaco (Burkart 1976; Kees et al. 2011). Interspecific hybrids also occur
between the different Prosopis species, giving rise to hybrid swarms in the contact
areas, the magnitude and extent of which would be influenced by the degree of natural or anthropogenic disturbance of the environment they occupy (Saidman et al.
2000; Mottura et al. 2005; Verga and Gregorius 2007).
In a dendrological study, Giménez and Moglia (2003a, b) identified 83 native
forest tree species (54 of them with at least 20 m of mean height) in 17 sampling
areas of the Chaco. In turn, the National Institute of Industrial Technology of
Argentina (INTI) highlighted 29 of them as of industrial interest. Among the
most important species due to their wood quality, chemical extracts, natural
range, ecological role, silviculture potential, and even cultural value, the following must be mentioned: the red quebrachos (Schinopsis spp.), Prosopis kuntzei,
Gonopterodendron sarmientoi, Caesalpinia paraguariensis, Handroanthus heptaphyllus, algarrobos (Prosopis spp.), Ziziphus mistol, Aspidosperma quebracho-blanco, and Enterolobium contortisiliquum.
8.2 Chaco and Deforestation: Two Words That Have Become
Synonymous in the Last Two Decades
The Chaco is one of the ecosystems with the highest deforestation rates of the world
(Hansen et al. 2013; Volante and Seghezzo 2018). The humid and dry Chaco subregions of Argentina have a great biological and productive diversity, cultural richness, as well as high levels of poverty and inequality (Paolasso et al. 2012). It has
experienced drastic changes in land use in recent times, leading to a dramatic deforestation throughout its entire extension. Likewise, during the first half of the twentieth century, the forests of S. balansae were devastated for tannin and sleeper
production. From the end of the twentieth century to the present day, in particular,
the semi-arid Chaco has suffered an intense deforestation in order to extend livestock farming and agriculture.
The social actors that occupy this region include large-scale capitalized farmers,
small-scale farmers (“puesteros’), indigenous communities and Mennonite settlers,
among others (Baldi et al. 2015). These actors interact with the environment in
multiple ways by capturing ecosystem services and modifying the environment
A. Verga and D. López Lauenstein
Prosopis nigra, while Prosopis chilensis and Prosopis flexuosa appear in the arid
Chaco (Galera 2000). However (see Chap. 9), genetic, taxonomic, and ecophysiological studies identify important differences between populations of P. alba distributed in the semi-arid and humid Chaco (Verga et al. 2009; Verga 2014). On the other
hand, a fifth species of algarrobo stands out in the north of the humid Chaco subregion: Prosopis hassleri. In Argentina it occupies only a strip of no more than 50 km
wide south of the Pilcomayo River (which forms the border with Paraguay), ranging
from the Paraguay River to the limit with the semi-arid Chaco. This is the southern
end of the distribution area of this species, whose center is located in the Paraguayan
humid Chaco (Burkart 1976; Kees et al. 2011). Interspecific hybrids also occur
between the different Prosopis species, giving rise to hybrid swarms in the contact
areas, the magnitude and extent of which would be influenced by the degree of natural or anthropogenic disturbance of the environment they occupy (Saidman et al.
2000; Mottura et al. 2005; Verga and Gregorius 2007).
In a dendrological study, Giménez and Moglia (2003a, b) identified 83 native
forest tree species (54 of them with at least 20 m of mean height) in 17 sampling
areas of the Chaco. In turn, the National Institute of Industrial Technology of
Argentina (INTI) highlighted 29 of them as of industrial interest. Among the
most important species due to their wood quality, chemical extracts, natural
range, ecological role, silviculture potential, and even cultural value, the following must be mentioned: the red quebrachos (Schinopsis spp.), Prosopis kuntzei,
Gonopterodendron sarmientoi, Caesalpinia paraguariensis, Handroanthus heptaphyllus, algarrobos (Prosopis spp.), Ziziphus mistol, Aspidosperma quebracho-blanco, and Enterolobium contortisiliquum.
8.2 Chaco and Deforestation: Two Words That Have Become
Synonymous in the Last Two Decades
The Chaco is one of the ecosystems with the highest deforestation rates of the world
(Hansen et al. 2013; Volante and Seghezzo 2018). The humid and dry Chaco subregions of Argentina have a great biological and productive diversity, cultural richness, as well as high levels of poverty and inequality (Paolasso et al. 2012). It has
experienced drastic changes in land use in recent times, leading to a dramatic deforestation throughout its entire extension. Likewise, during the first half of the twentieth century, the forests of S. balansae were devastated for tannin and sleeper
production. From the end of the twentieth century to the present day, in particular,
the semi-arid Chaco has suffered an intense deforestation in order to extend livestock farming and agriculture.
The social actors that occupy this region include large-scale capitalized farmers,
small-scale farmers (“puesteros’), indigenous communities and Mennonite settlers,
among others (Baldi et al. 2015). These actors interact with the environment in
multiple ways by capturing ecosystem services and modifying the environment
A. Verga and D. López Lauenstein