328
12.2 Alto Paraná Rainforest: Geographical Location,
Logging Background, and Conservation Status
The Alto Paraná Rainforest, locally called Selva Misionera, concentrates the largest
plant biodiversity of Argentina in less than 0.5% of the national territory, with more
than 2800 vascular plant species (Zuloaga et al. 1999). However, it is probably the
least studied unit of forest vegetation in the country and is currently affected by the
fastest rate of urbanization. It extends to the two neighboring countries (Southwest
Brazil and East Paraguay) and consists mainly of multistratified subtropical forests,
marginal forests or riverbanks in large rivers, and even savannas in the south of the
Province of Misiones. It is located at the Northeast end of Argentina and covers
almost 30,000 km
2
. It has a humid subtropical climate, with annual rainfall of
1700–2400 mm, distributed evenly during the year. The average temperature of
January is 25 °C, with an absolute maximum of 39 °C, while the average of the
coldest month is 15 °C (Burgos 1970; Margalot 1985).
Physiographic variations make it possible to divide this rainforest into five geomorphological regions: Serrana, Paraná Coastal, Uruguay Coastal, Southern Plains,
and Plains Region. It is possible to establish a physiognomic correspondence
between these geomorphological regions and the phytogeographic units proposed
by Martínez Crovetto (1963), who divides the Selva Misionera into five Districts:
Laureles’ District, Palo Rosa’s District, Tree Fern’s District, Urunday’s District, and
Fluvial District (Paranaense and Paraguayense sub-districts). However, Cabrera
(1971) divides the Alto Paraná Rainforest into two zones called (1) “Selvas Mixtas”
District, which occupies the North of the Province of Misiones, including the coastal
communities along the Paraná and Uruguay rivers, and (2) “Campos” District in the
South of the Province of Misiones and the North of the Province of Corrientes,
which has an edaphic character related to shallowness (Martínez Crovetto 1963)
and is constituted by herbaceous communities with predominant presence of the
tree Myracrodruon balansae.
The “Selvas Mixtas” District includes three tree communities (sub-districts):
“Laurel, Guatambú, and Palo Rosa Rainforest,” “Laurel, Guatambú, and Paraná
Pine Rainforest,” and “Urunday Forest.” The first sub-district is characterized by the
ostensible presence of two species with greater thermal and water requirements,
which are very affected by the overexploitation: Aspidosperma polyneuron (Palo
Rosa) and Euterpe edulis (Palmito), a graceful stipe palm with edible inner core and
growing bud (heart of palm), whose extraction causes its death. They are accompanied by Holocalyx balansae and numerous exclusive species of this particular and
limited ecosystem.
The tree ferns community occurs in the valleys of the tributaries of the Uruguay
River and in the lower parts of the central mountains. It is characterized by the abundance of several species of tree ferns, which dominate the undergrowth in the few
relics of this formation that have still managed to persist in pristine state. The
“Laurel, Guatambú, and Paraná Pine” sub-district occupies the Northeast end of
Misiones, in the highest altitude regions and with a slightly colder climate. Martínez
L. F. Fornes
12.2 Alto Paraná Rainforest: Geographical Location,
Logging Background, and Conservation Status
The Alto Paraná Rainforest, locally called Selva Misionera, concentrates the largest
plant biodiversity of Argentina in less than 0.5% of the national territory, with more
than 2800 vascular plant species (Zuloaga et al. 1999). However, it is probably the
least studied unit of forest vegetation in the country and is currently affected by the
fastest rate of urbanization. It extends to the two neighboring countries (Southwest
Brazil and East Paraguay) and consists mainly of multistratified subtropical forests,
marginal forests or riverbanks in large rivers, and even savannas in the south of the
Province of Misiones. It is located at the Northeast end of Argentina and covers
almost 30,000 km
2
. It has a humid subtropical climate, with annual rainfall of
1700–2400 mm, distributed evenly during the year. The average temperature of
January is 25 °C, with an absolute maximum of 39 °C, while the average of the
coldest month is 15 °C (Burgos 1970; Margalot 1985).
Physiographic variations make it possible to divide this rainforest into five geomorphological regions: Serrana, Paraná Coastal, Uruguay Coastal, Southern Plains,
and Plains Region. It is possible to establish a physiognomic correspondence
between these geomorphological regions and the phytogeographic units proposed
by Martínez Crovetto (1963), who divides the Selva Misionera into five Districts:
Laureles’ District, Palo Rosa’s District, Tree Fern’s District, Urunday’s District, and
Fluvial District (Paranaense and Paraguayense sub-districts). However, Cabrera
(1971) divides the Alto Paraná Rainforest into two zones called (1) “Selvas Mixtas”
District, which occupies the North of the Province of Misiones, including the coastal
communities along the Paraná and Uruguay rivers, and (2) “Campos” District in the
South of the Province of Misiones and the North of the Province of Corrientes,
which has an edaphic character related to shallowness (Martínez Crovetto 1963)
and is constituted by herbaceous communities with predominant presence of the
tree Myracrodruon balansae.
The “Selvas Mixtas” District includes three tree communities (sub-districts):
“Laurel, Guatambú, and Palo Rosa Rainforest,” “Laurel, Guatambú, and Paraná
Pine Rainforest,” and “Urunday Forest.” The first sub-district is characterized by the
ostensible presence of two species with greater thermal and water requirements,
which are very affected by the overexploitation: Aspidosperma polyneuron (Palo
Rosa) and Euterpe edulis (Palmito), a graceful stipe palm with edible inner core and
growing bud (heart of palm), whose extraction causes its death. They are accompanied by Holocalyx balansae and numerous exclusive species of this particular and
limited ecosystem.
The tree ferns community occurs in the valleys of the tributaries of the Uruguay
River and in the lower parts of the central mountains. It is characterized by the abundance of several species of tree ferns, which dominate the undergrowth in the few
relics of this formation that have still managed to persist in pristine state. The
“Laurel, Guatambú, and Paraná Pine” sub-district occupies the Northeast end of
Misiones, in the highest altitude regions and with a slightly colder climate. Martínez
L. F. Fornes