Río Pilcomayo National Park
Encyclopedia
The Río Pilcomayo National Park is a national park
located in the northeastern part of the Argentine
province of Formosa
, on the border with Paraguay
. Established on September 29, 1951 to protect the natural features (grasslands, marshes, creeks, lakes and forests), typical of the Humid Chaco ecoregion
, the park is included in the Ramsar Convention
's list of wetlands of international importance.
, which was formed when a depression in Paleozoic
crystalline rocks was filled with organic and inorganic sediment
s, thus creating a sedimentary basin
. The uppermost sediment levels are of fluvial
and aeolian origin. The eastern parts of the park are dominated by silt
s and clay
s, creating less permeable soils, while the western parts contain soils that are coarser and more porous.
There are fault line
s that were generated during formation
of the Andes
, lying parallel to the Paraguay River
. While the park's territory is gently sloping down from west to east, there is very little variety in elevation. The subtle differences become important in times of heavy rains and floods, when the area becomes inundated with pools of water connected by channels forming in the most low lying areas.
, after which the park is named, is the main watercourse of the area. During the wet season, the river and its tributaries flood the nearby areas, creating large swaths of interconnected lakes and marshes, most of which are temporary. The southern end of the park contains a larger lake called Laguna Blanca, which is a habitat for many waterfowl
species and a resting point for migratory bird species coming from the Northern hemisphere
.
es.
, which is dominated by the Caranday wax palm, an unofficial emblem of the area, towering over a dense cover of herbaceous plant
s (especially from the Scirpus
genus). Other trees include such species as Acacia caven
and Prosopis nigra
.
Wetlands are dominated by aquatic vegetation. Floating plants include water hyacinth
s, Limnocharitaceae
, Nymphoides
and Ludwigia
.
Another distinct zone is adjacent to the Pilcomayo River and its former channels, which are frequently flooded. It is dominated by riparian vegetation. Figs
and sweetwood trees can be found there, covered by many species of lianas, vine
s and epiphyte
s.
The patchy vegetation of the higher lands, forming distinctive "mountain islands", represent the fourth zone. Quebracho tree
s (Schinopsis balansae
and Aspidosperma quebracho-blanco
) can frequently be found there.
, capybara
, peccary
, howler monkey
and puma; birds include chachalaca
s and rails
. The Maned Wolf
can be found in the lowlands, along with such birds as the Greater Rhea and seriema
s.
Aquatic environments are inhabited by stork
s, heron
s, Roseate Spoonbill
s and duck
s. There are two caiman
species: the Broad-snouted Caiman
and the Yacare Caiman
. The fish population includes species from the Hoplosternum
genus that can use atmospheric air and thus tolerate droughts that frequently affect shallow water bodies in the area.
The snake population is represented by the Boidae family and includes such species as Eunectes notaeus
and Eunectes murinus. Hydrodynastes gigas, a venomous water snake, is also found in the area.
National park
A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or owns. Although individual nations designate their own national parks differently A national park is a reserve of natural, semi-natural, or developed land that a sovereign state declares or...
located in the northeastern part of the Argentine
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
province of Formosa
Formosa Province
Formosa Province is in northeastern Argentina, part of the Gran Chaco Region. Its northeast end touches Asunción, Paraguay, and borders the provinces of Chaco and Salta to its south and west, respectively...
, on the border with Paraguay
Paraguay
Paraguay , officially the Republic of Paraguay , is a landlocked country in South America. It is bordered by Argentina to the south and southwest, Brazil to the east and northeast, and Bolivia to the northwest. Paraguay lies on both banks of the Paraguay River, which runs through the center of the...
. Established on September 29, 1951 to protect the natural features (grasslands, marshes, creeks, lakes and forests), typical of the Humid Chaco ecoregion
Ecoregion
An ecoregion , sometimes called a bioregion, is an ecologically and geographically defined area that is smaller than an ecozone and larger than an ecosystem. Ecoregions cover relatively large areas of land or water, and contain characteristic, geographically distinct assemblages of natural...
, the park is included in the Ramsar Convention
Ramsar Convention
The Ramsar Convention is an international treaty for the conservation and sustainable utilization of wetlands, i.e., to stem the progressive encroachment on and loss of wetlands now and in the future, recognizing the fundamental ecological functions of wetlands and their economic, cultural,...
's list of wetlands of international importance.
Topography
The park occupies a large plainPlain
In geography, a plain is land with relatively low relief, that is flat or gently rolling. Prairies and steppes are types of plains, and the archetype for a plain is often thought of as a grassland, but plains in their natural state may also be covered in shrublands, woodland and forest, or...
, which was formed when a depression in Paleozoic
Paleozoic
The Paleozoic era is the earliest of three geologic eras of the Phanerozoic eon, spanning from roughly...
crystalline rocks was filled with organic and inorganic sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
s, thus creating a sedimentary basin
Sedimentary basin
The term sedimentary basin is used to refer to any geographical feature exhibiting subsidence and consequent infilling by sedimentation. As the sediments are buried, they are subjected to increasing pressure and begin the process of lithification...
. The uppermost sediment levels are of fluvial
Fluvial
Fluvial is used in geography and Earth science to refer to the processes associated with rivers and streams and the deposits and landforms created by them...
and aeolian origin. The eastern parts of the park are dominated by silt
Silt
Silt is granular material of a size somewhere between sand and clay whose mineral origin is quartz and feldspar. Silt may occur as a soil or as suspended sediment in a surface water body...
s and clay
Clay
Clay is a general term including many combinations of one or more clay minerals with traces of metal oxides and organic matter. Geologic clay deposits are mostly composed of phyllosilicate minerals containing variable amounts of water trapped in the mineral structure.- Formation :Clay minerals...
s, creating less permeable soils, while the western parts contain soils that are coarser and more porous.
There are fault line
Fault line
In geology, fault line refers to the surface trace of a fault.Fault line, Fault Line, or faultline may also refer to:* "Faultline", a song from the 2008 studio album Versus by The Haunted...
s that were generated during formation
Orogeny
Orogeny refers to forces and events leading to a severe structural deformation of the Earth's crust due to the engagement of tectonic plates. Response to such engagement results in the formation of long tracts of highly deformed rock called orogens or orogenic belts...
of the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
, lying parallel to the Paraguay River
Paraguay River
The Paraguay River is a major river in south central South America, running through Brazil, Bolivia, Paraguay, and Argentina...
. While the park's territory is gently sloping down from west to east, there is very little variety in elevation. The subtle differences become important in times of heavy rains and floods, when the area becomes inundated with pools of water connected by channels forming in the most low lying areas.
Hydrography
The Pilcomayo RiverPilcomayo River
The Pilcomayo River is a river in central South America. At long, it is the longest western tributary of the Paraguay River. Its drainage basin is in area, and its mean discharge is ....
, after which the park is named, is the main watercourse of the area. During the wet season, the river and its tributaries flood the nearby areas, creating large swaths of interconnected lakes and marshes, most of which are temporary. The southern end of the park contains a larger lake called Laguna Blanca, which is a habitat for many waterfowl
Waterfowl
Waterfowl are certain wildfowl of the order Anseriformes, especially members of the family Anatidae, which includes ducks, geese, and swans....
species and a resting point for migratory bird species coming from the Northern hemisphere
Northern Hemisphere
The Northern Hemisphere is the half of a planet that is north of its equator—the word hemisphere literally means “half sphere”. It is also that half of the celestial sphere north of the celestial equator...
.
Climate
The park is located in a subtropical zone with annual mean temperature of 23 °C (73.4 °F) and annual mean precipitation of 1200 millimetres (47.2 in). Summer temperatures can exceed 40 °C (104 °F), but during winters, frost is not uncommon. Winters are dry, while precipitation peaks in March and November. The area is affected by frequent tornadoTornado
A tornado is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud. They are often referred to as a twister or a cyclone, although the word cyclone is used in meteorology in a wider...
es.
Flora
For the purposes of classifying the park's types of plants, the area can be divided into 4 distinct zones. One is savannaSavanna
A savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...
, which is dominated by the Caranday wax palm, an unofficial emblem of the area, towering over a dense cover of herbaceous plant
Herbaceous plant
A herbaceous plant is a plant that has leaves and stems that die down at the end of the growing season to the soil level. They have no persistent woody stem above ground...
s (especially from the Scirpus
Scirpus
The plant genus Scirpus consists of a large number of aquatic, grass-like species in the family Cyperaceae , many with the common names club-rush or bulrush . Other common names are deergrass or grassweed.The genus has a cosmopolitan distribution, and grows in wetlands and moist soil...
genus). Other trees include such species as Acacia caven
Acacia caven
Acacia caven is an ornamental tree in the Fabaceae family. Acacia caven is native to Argentina, Bolivia, Chile, Paraguay, and Uruguay...
and Prosopis nigra
Prosopis nigra
Prosopis nigra is a South American leguminous tree species that inhabits the Gran Chaco ecoregion , in Argentina and Paraguay...
.
Wetlands are dominated by aquatic vegetation. Floating plants include water hyacinth
Water hyacinth
The seven species of water hyacinth comprise the genus Eichhornia. Water hyacinth are a free-floating perennial aquatic plant native to tropical and sub-tropical South America. With broad, thick, glossy, ovate leaves, water hyacinth may rise above the surface of the water as much as 1 meter in...
s, Limnocharitaceae
Limnocharitaceae
Limnocharitaceae is the botanical name of a family of flowering plants in the monocot order Alismatales. It is commonly known as the water poppy family. They are small, perennial, aquatic herbs, native to the tropics, but adventive or naturalized in the subtropics as a result of...
, Nymphoides
Nymphoides
Nymphoides is a genus of aquatic flowering plants in the family Menyanthaceae. The genus name refers to their resemblance to the water lily Nymphaea. Nymphoides are aquatic plants with submerged roots and floating leaves that hold the small flowers above the water surface. Flowers are sympetalous,...
and Ludwigia
Ludwigia
Ludwigia is a genus of about 75 species of aquatic plants with a cosmopolitan but mainly tropical distribution.Selected species...
.
Another distinct zone is adjacent to the Pilcomayo River and its former channels, which are frequently flooded. It is dominated by riparian vegetation. Figs
FIGS
FIGS is an acronym for French, Italian, German, Spanish. These are usually the first four languages chosen to localize products into when a company enters the European market....
and sweetwood trees can be found there, covered by many species of lianas, vine
Vine
A vine in the narrowest sense is the grapevine , but more generally it can refer to any plant with a growth habit of trailing or scandent, that is to say climbing, stems or runners...
s and epiphyte
Epiphyte
An epiphyte is a plant that grows upon another plant non-parasitically or sometimes upon some other object , derives its moisture and nutrients from the air and rain and sometimes from debris accumulating around it, and is found in the temperate zone and in the...
s.
The patchy vegetation of the higher lands, forming distinctive "mountain islands", represent the fourth zone. Quebracho tree
Quebracho tree
Quebracho is a common name in Spanish to describe very hard wood tree species. The etymology of the name derived from quiebrahacha, or quebrar hacha, meaning "axe-breaker".-Species:...
s (Schinopsis balansae
Schinopsis balansae
Schinopsis balansae is a hardwood tree which forms forests in the subtropical Gran Chaco ecoregion of north-eastern Argentina, and Paraguay. It is also found in the wild Pantanal vegetation in Brazil. Some of its common names are quebracho colorado chaqueño and quebracho santafesino...
and Aspidosperma quebracho-blanco
Aspidosperma quebracho-blanco
Quebracho blanco is a South American tree species, which is found in the northern regions of Argentina. It must not be confused with other species also known as quebracho, but belonging to the genus Schinopsis.-Growth:Quebracho blanco wood is uniformly yellow-ochre, without differences between...
) can frequently be found there.
Fauna
Higher lands are inhabited by such mammals as the Gray BrocketGray Brocket
The Gray Brocket , also known as the brown brocket, is a species of brocket deer from northern Argentina, Bolivia, eastern and southern Brazil, Paraguay and Uruguay. It formerly included the Amazonian Brown Brocket and sometimes also the Yucatan Brown Brocket as subspecies...
, capybara
Capybara
The capybara , also known as capivara in Portuguese, and capibara, chigüire in Venezuela, Colombia, and Ecuador ronsoco in Peru, chigüiro, and carpincho in Spanish, is the largest living rodent in the world. Its closest relatives are agouti, chinchillas, coyphillas, and guinea pigs...
, peccary
Peccary
A peccary is a medium-sized mammal of the family Tayassuidae, or New World Pigs. Peccaries are members of the artiodactyl suborder Suina, as are the pig family and possibly the hippopotamus family...
, howler monkey
Howler monkey
Howler monkeys are among the largest of the New World monkeys. Fifteen species are currently recognised. Previously classified in the family Cebidae, they are now placed in the family Atelidae. These monkeys are native to South and Central American forests...
and puma; birds include chachalaca
Chachalaca
Chachalacas are mainly brown birds from the genus Ortalis. These cracids are found in wooded habitats in far southern United States , Mexico, and Central and South America. They are social, can be very noisy and often remain fairly common even near humans, as their relatively small size makes them...
s and rails
Rallidae
The rails, or Rallidae, are a large cosmopolitan family of small to medium-sized birds. The family exhibits considerable diversity and the family also includes the crakes, coots, and gallinules...
. The Maned Wolf
Maned Wolf
The maned wolf is the largest canid of South America, resembling a large fox with reddish fur.This mammal is found in open and semi-open habitats, especially grasslands with scattered bushes and trees, in south, central-west and south-eastern Brazil The maned wolf (Chrysocyon brachyurus) is the...
can be found in the lowlands, along with such birds as the Greater Rhea and seriema
Seriema
The seriemas are the sole extant members of the small and ancient family Cariamidae, which is also the sole surviving family of the Cariamae. Once believed to be related to cranes, they have been placed by one recent study near the falcons, parrots and passerines, as well as the extinct terror birds...
s.
Aquatic environments are inhabited by stork
Stork
Storks are large, long-legged, long-necked wading birds with long, stout bills. They belong to the family Ciconiidae. They are the only family in the biological order Ciconiiformes, which was once much larger and held a number of families....
s, heron
Heron
The herons are long-legged freshwater and coastal birds in the family Ardeidae. There are 64 recognised species in this family. Some are called "egrets" or "bitterns" instead of "heron"....
s, Roseate Spoonbill
Roseate Spoonbill
The Roseate Spoonbill, Platalea ajaja, is a gregarious wading bird of the ibis and spoonbill family, Threskiornithidae...
s and duck
Duck
Duck is the common name for a large number of species in the Anatidae family of birds, which also includes swans and geese. The ducks are divided among several subfamilies in the Anatidae family; they do not represent a monophyletic group but a form taxon, since swans and geese are not considered...
s. There are two caiman
Caiman
Caimans are alligatorid crocodylians within the subfamily Caimaninae. The group is one of two subfamilies of the family Alligatoridae, the other being alligators. Caimans inhabit Central and South America. They are relatively small crocodilians, with most species reaching lengths of only a few...
species: the Broad-snouted Caiman
Broad-snouted Caiman
The broad-snouted caiman is a crocodilian reptile found in eastern and central South America, including southeastern Brazil, northern Argentina, Uruguay, Paraguay and Bolivia. It is found mostly in freshwater marshes, swamps, and mangroves. Usually, in still or very slow moving waters...
and the Yacare Caiman
Yacare Caiman
The Yacare caiman is a species of caiman found in central South America, including northeastern Argentina, Uruguay eastern Bolivia, central/south-west Brazil, and the rivers of Paraguay...
. The fish population includes species from the Hoplosternum
Hoplosternum
Hoplosternum is a small genus of freshwater catfish in the Callichthyinae subfamily of the armored catfish family, and consists of 3 species from South America, H. littorale, H. magdalenae, and H...
genus that can use atmospheric air and thus tolerate droughts that frequently affect shallow water bodies in the area.
The snake population is represented by the Boidae family and includes such species as Eunectes notaeus
Eunectes notaeus
Eunectes notaeus is a non-venomous boa species found in South America. No subspecies are currently recognized.-Description:Adults are not as large as the green anaconda, E. murinus, but nevertheless grow to an average of in length. The maximum size is almost certainly larger...
and Eunectes murinus. Hydrodynastes gigas, a venomous water snake, is also found in the area.