Ansenuza

Mar Chiquita National Park protects the Mar Chiquita coastal lagoon system in Córdoba Province, central Argentina, covering approximately 27,000 hectares. Established as a provincial reserve and later elevated to national park status, it encompasses one of the world's largest saline lagoons and the surrounding monte shrubland and salt flat ecosystems. The lagoon's salinity fluctuates dramatically with rainfall cycles, creating a dynamic ecosystem of continental importance. It is recognized as a Ramsar Wetland of International Importance and a UNESCO Biosphere Reserve.

Mar Chiquita is one of South America's most important waterbird habitats. Three flamingo species—the Andean, James's, and Chilean flamingo—gather in tens of thousands to feed on brine shrimp and algae. Migratory shorebirds from North America, including sandpipers and plovers, stop here along the Central Americas Flyway. More than 200 bird species have been recorded, including buff-necked ibis, roseate spoonbill, and several threatened species. The lagoon supports large populations of brine shrimp (Artemia) and brine flies, which sustain the flamingo populations.

The park encompasses distinct vegetation zones transitioning from salt flat communities adjacent to the lagoon to monte shrubland on higher ground. Salt-tolerant plants including glasswort (Salicornia), sea purslane, and alkali grasses colonize the shoreline. The monte shrubland is dominated by jarilla (Larrea) species and quebracho blanco (Aspidosperma quebracho-blanco). Gallery forests of algarrobo (Prosopis) and chañar (Geoffroea decorticans) follow watercourses. Aquatic plants and algae support the lagoon's invertebrate food web.

Mar Chiquita occupies a shallow endorheic basin in the Pampean sedimentary plain, with no outlet to the ocean. The lagoon formed in a tectonic depression that traps water from the Dulce, Primero, and Segundo rivers. The basin floor consists of Quaternary lacustrine sediments and evaporite deposits including halite and gypsum. Salt crusts form at the margins during dry periods. The surrounding landscape is one of the flattest in Argentina, with relief rarely exceeding 30 meters. Periodic flooding cycles have deposited alternating layers of clay and salt over thousands of years.

The region experiences a semi-arid to sub-humid continental climate with warm summers and mild winters. Annual rainfall averages 600–700 mm, highly variable between years, which directly controls the lagoon's water level and salinity. The 20th century saw dramatic fluctuations: the lagoon rose by over 7 meters between 1977 and 1986 due to wet cycles, flooding surrounding agricultural land. Temperatures range from 0–5°C in winter nights to 30–35°C in summer. The flatness of the terrain means strong winds are frequent, and dust storms can occur in dry periods.

Indigenous Comechingón and Sanavirón peoples inhabited the region surrounding Mar Chiquita for centuries before Spanish contact, fishing its productive waters and hunting along its shores. Spanish explorers reached the area in the 16th century, and the settlement of Córdoba in 1573 brought colonial influence to the region. The lagoon's dramatic size fluctuations confused early European mapmakers, who variously mapped it as large or small depending on the decade of observation. The word 'Mar Chiquita' (Little Sea) reflects its vast appearance from shore.

The Mar Chiquita area has been protected under various provincial designations since the late 20th century. It was declared a Ramsar Wetland of International Importance in 2002 and a UNESCO Man and Biosphere Reserve in 2002 as part of the Ansenuza Biosphere Reserve. Argentina's Congress elevated it to National Park status in 2022, creating Mar Chiquita National Park (officially named Parque Nacional Ansenuza), establishing formal federal protection for this globally significant wetland. The designation marked a major conservation milestone for South American inland waters.

The town of Miramar de Ansenuza on the lagoon's southern shore serves as the main visitor hub, offering views of flamingo flocks. Boat tours on the lagoon provide close-up access to flamingo feeding areas and shorebird concentrations. Observation towers and hides have been established for birdwatching. The 'salt beaches' of the lagoon edge offer a surreal landscape experience. Annual flamingo counts attract researchers and wildlife photographers. The surrounding monte provides habitat for mammals including maras (Patagonian hares), pumas, and foxes.

Miramar de Ansenuza, a small town on the lagoon's shore, offers hotels, restaurants, and boat tour operators. The town is reached by paved road from Córdoba city (approximately 170 km north). Local guides are recommended for birdwatching tours. The park's visitor infrastructure is still developing following its 2022 national park designation. Binoculars and a spotting scope are essential for flamingo and shorebird observation. The best viewing conditions are typically in the dry season (May–October) when water levels are lower and birds are concentrated.

The lagoon faces threats from agricultural runoff, particularly fertilizers and pesticides from soy and cattle operations that surround the basin. Water diversion from the Dulce River for irrigation has reduced inflow. The dramatic water level rise of the late 20th century caused property damage in surrounding towns and altered the ecosystem. Climate change threatens to increase drought frequency, potentially raising salinity to levels incompatible with flamingo breeding. The new national park status provides a stronger legal framework for protecting the watershed, though managing upstream agricultural pressures remains the primary challenge.