Iberá

Iberá Provincial Reserve protects approximately 1.3 million hectares (13,000 km²) of wetlands, marshes, lagoons, and grasslands in the northeastern Argentine province of Corrientes, forming the second-largest wetland system in the world after the Pantanal. ^[1] Created on April 15, 1983, under Provincial Law No. 3771, the reserve surrounds the Esteros del Iberá, a vast mosaic of shallow lakes and floating vegetation islands known as embalsados. ^[1] The reserve is internationally renowned for its extraordinary biodiversity and for pioneering rewilding efforts led by Rewilding Argentina (formerly Conservation Land Trust Argentina), which reintroduced locally extinct species such as the jaguar, giant anteater, and green-winged macaw. Core sectors of the reserve have since been designated as Iberá National Park (established 2018), though the provincial reserve—at 13,000 km²—remains the dominant conservation unit and the largest protected area in Argentina.

Iberá hosts one of the richest concentrations of wildlife in Argentina, with more than 360 bird species and numerous mammals, reptiles, and amphibians. ^[1] Capybaras and marsh deer are abundant along the waterways, while yacaré caiman and broad-snouted caiman share the lagoons with anaconda and swamp rats. The reserve has become famous for its rewilding program, which has successfully reintroduced jaguars, giant anteaters, giant otters, pampas deer, collared peccaries, and red-and-green macaws. Birdlife includes jabiru storks, roseate spoonbills, southern screamers, strange-tailed tyrants, and the endangered saffron-cowled blackbird. Howler monkeys call from forested islands, and the wetlands support thriving populations of neotropical river otters.

The reserve's vegetation reflects its semi-aquatic character, dominated by floating mats of vegetation called embalsados that support water hyacinth, pickerelweed, and floating ferns. Extensive marshes of cattails, bulrushes, and sedges fringe the open lagoons. Higher ground supports palm savannas of yatay (Butia yatay) and caranday (Copernicia alba) palms, interspersed with gallery forests along creeks and on ancient dune ridges. These forests contain timbó, lapacho, espinillo, and urunday trees. Grasslands of paja colorada stretch across drier sectors, while water lilies, including the giant Victoria cruziana, adorn calmer backwaters. The mixture of aquatic, savanna, and forest communities creates exceptional ecological diversity within a compact region.

The Iberá wetlands occupy an ancient paleochannel of the Paraná River, formed when the river shifted course thousands of years ago and left behind a vast shallow depression between elevated sandy ridges. ^[1] The underlying basement consists of Quaternary alluvial sediments overlying older sandstone formations of the Paraná sedimentary basin. Sandy cordons, some reaching 60 to 70 meters above sea level, mark former riverbanks and now host terrestrial habitats among the marshes. The wetland receives water almost entirely from rainfall rather than river inflow, creating a largely closed hydrological system with the Corriente River as its main outlet. Shallow lagoons, peat deposits, and floating vegetation mats continue to shape a dynamic, evolving landscape.

Iberá experiences a humid subtropical climate with hot, wet summers and mild, drier winters. Annual rainfall averages between 1,200 and 1,700 millimeters, distributed relatively evenly throughout the year but with peaks in late spring and early autumn. Summer temperatures from December through February regularly exceed 35°C, with high humidity making conditions oppressive during midday hours. Winter months from June to August bring cooler weather, with averages between 10°C and 22°C, though occasional cold fronts from Patagonia can push temperatures near freezing at dawn. The most comfortable visiting period runs from April through October, when mosquitoes are less abundant and wildlife viewing along the waterways is most productive.

The wetlands have been inhabited for millennia by Guaraní peoples, whose name Y Berá, meaning shining waters, gave the region its modern designation. Guaraní communities fished, hunted, and gathered across the marshes, leaving behind ceramic fragments and earthworks on the sandy ridges. Jesuit missionaries arrived in the 17th century and established nearby reductions, introducing cattle ranching that would shape the region for centuries. After Jesuit expulsion in 1767, large estancias dominated the area, and gauchos developed distinctive cultural traditions adapted to the wetland environment. By the late 20th century, hunting, habitat loss, and overgrazing threatened many species, prompting the provincial government and private conservation organizations to intervene.

The Iberá Provincial Reserve was created on April 15, 1983, by Corrientes Province through Law 3771, to protect the ecological integrity of the Esteros del Iberá. ^[1] For decades the reserve faced challenges from cattle grazing, illegal hunting, and drainage schemes. In the late 1990s, American philanthropists Douglas and Kristine Tompkins began acquiring former ranchlands within the reserve through Conservation Land Trust Argentina, launching an ambitious rewilding initiative. Over subsequent decades they purchased and restored hundreds of thousands of hectares, reintroducing extirpated species and eventually donating key lands that became Iberá National Park in 2018. A portion of the reserve was designated a Ramsar Wetland of International Importance in 2002. The provincial reserve continues to form the larger protective buffer around the national park.

Colonia Carlos Pellegrini on the shore of Laguna Iberá serves as the reserve's main access point and offers guided boat tours, horseback rides, and walking trails. The Ñandú, Lobo Cuá, and Yacaré interpretive trails wind through gallery forest and palm savanna near the visitor center, providing excellent chances to see howler monkeys, marsh deer, and capybaras. Night safaris reveal yacaré caiman eyes glowing across the lagoons. Other entry portals include Cambyretá in the north, San Nicolás in the east, Uguay in the west, and Río near Concepción, each offering distinct landscapes and wildlife experiences. Canoe excursions into the embalsados allow close observation of water birds and aquatic plants.

Colonia Carlos Pellegrini is reached by a 120-kilometer unpaved road from Mercedes, the nearest major town served by bus from Buenos Aires and Posadas. Four-wheel drive is recommended during wet weather. The village offers accommodations ranging from rustic posadas to upscale ecolodges, most of which arrange guided excursions. Local boatmen provide motorized and paddled tours of Laguna Iberá, while horseback riding through palm savannas is a signature activity. A small provincial visitor center provides interpretation about the ecosystem and rewilding projects. Cell coverage is patchy throughout the reserve, and visitors should bring cash, insect repellent, and sun protection.

Iberá stands as one of South America's most ambitious conservation success stories. The rewilding program led by Rewilding Argentina has returned jaguars, giant anteaters, tapirs, collared peccaries, giant otters, pampas deer, and red-and-green macaws to landscapes where they had been extirpated. ^[1] The reserve has also supported fire management, invasive species control, and the transition of former ranchlands to native ecosystems. Local communities benefit from ecotourism employment, guiding services, and artisan cooperatives, helping shift the regional economy from extractive industries to conservation-based livelihoods. Ongoing threats include afforestation with exotic pines, proposed drainage for agriculture, and climate-driven changes to rainfall patterns that could alter the wetlands' delicate hydrological balance.