Laguna Oca y Herraduras del Río Paraguay Biosphere Reserve

The Laguna Oca y Herraduras del Río Paraguay Biosphere Reserve is located along a meandering bend of the Paraguay River near Formosa in northern Argentina.

The area of the Biosphere Reserve constitutes part of the alluvial plain governed by the Paraguay River's action. It comprises arms of the main river channel, semilunar lagoons, which include the Oca Lagoon, internal deltas and embankments. It also includes a portion of the Chaco plains.

The surface area of the Laguna Oca y Herraduras del Río Paraguay Biosphere Reserve is 63,029 ha (155,748 acres). Of the total surface area, 1,280 ha (3,163 acres) constitute the core area, 11,590 ha (12,637 acres) constitute the buffer zones, and 40,564 ha (100,235 acres) constitute the transition zones.

Flora

The natural vegetation of the Reserve comprises gallery forests, wetlands, and savannas along the meanders and oxbow lakes of the Paraguay River. The gallery forests are densely structured, containing high biodiversity, with abundant epiphytes, lianas, and orchids.

The most prevalent woody species include the genus Prosopis such as the white carob tree (Prosopis alba), the black carob tree (Prosopis nigra) and espinillo (Prosopis affinis); species of the genus Tabebuia such as the Palo Cruz (Tabebuia nodosa) and in lesser abundance, the paratodo (Tanebuia aurea), tatané (Chloroleucon tenuiflorum) and quebrachillo (Aspidosperma triternatum). Caranday palm (Copernicia alba) is also dispersed throughout.

Bush species include the churqui (Acacia caven) and the aromito (Acacia Aroma). The herbaceous species include those of the Poaceae family, the most notable of which include: espartillo (Elionurus muticus), paja boba (Paspalum intermedum) and paja brava (Panicum prionitis).

Near Payaguá Island and Laguna Verde, almost pure manduvira (Cynometra bauhiniaefolia) forests exist, and regeneration has been observed in those environments.

Fauna

The vertebrates found in the Reserve include more than 50 species of fish, forty amphibians, 50 reptiles, 300 birds and 70 mammals. Probably the most significant number of species corresponds to the group of insects, among which ants stand out as the primary biomass in the region.

Within the group of reptiles and amphibians, the following species are notable: black caiman (Caiman yacare), yacaré overo (Caiman latirostris), false chameleon (Polychrus acutirostris), cururú toad (Rhinella schneideri), Chaco climbing frog (Hypsiboas raniceps), Chaco snout frog (Scinax acuminatus), spotted-breasted frog (Scinax nasicus), dwarf climbing frog (Dendropsophus nanus), Chaco frog (Leptodactylus chaquensis), Chaco toad (Melanophryniscus klappenbachi), sheep iguana (Tupinambis merianae), and large yarara (Bothrops alternatus).

The Reserve is the habitat of numerous species of birds, among which are frequent sightings of the common tataupá (Crypturellus tataupa), the picazuró pigeon (Patagioenas picazuro), the common yeruti (Leptotila verreauxi), the common hummingbird (Chlorostilbon lucidus) the tan (Hylocharis chrysura), the small anno (Crotophaga ani), the bald-faced raven (Phimosus infuscatus), the blue heron (Butorides striata), the black heron (Ardea cocoi), the biguá (Nannopterum brasilianus), the common tero (Vanellus chilensis), three varieties of kingfisher (Megaceryle torquata), (Chloroceryle amazona) and (Chloroceryle americana), the common woodpecker (Colaptes melanolaimus), the caracara (Caracara plancus), and several dozen species of songbirds.

The characteristics of the environment favor the presence of butterflies, such as the granadilla tiger (Dryadula phaetusa), the little mirror (Agraulis vanillae), the yuyera (Leptotes cassius), the peacock (Junonia genoveva) and the golden border (Battus polydamas), among others.