Carlos Anwandter Nature Sanctuary () is protected wetland in

Cruces River The Cruces River () is a river in south-central Chile. Río Cruces originates from hills near the Villarica volcano and flows then in south-west direction. The southern and final part of the river flows in a south-south-west direction followin ...

about north of

Valdivia Valdivia (; Mapuche: Ainil) is a city and commune in southern Chile, administered by the Municipality of Valdivia. The city is named after its founder, Pedro de Valdivia, and is located at the confluence of the Calle-Calle, Valdivia, and ...

Chile Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...

. The sanctuary is named after the German politician

Carlos Anwandter Carlos Anwandter (1 April 1801, in Luckenwalde, Prussia – 10 July 1889, in Valdivia, Chile) was a German political exile who emigrated to Valdivia, Chile in 1850 after participating in the Revolutions of 1848. Biography He migrated to Valdi ...

who settled in Valdivia in 1850. This sanctuary provides a home for many native waterbird species to flourish, and contains roughly 119 species of birds alone. The most numerous bird species in the sanctuary are the black-necked swans followed by

coot Coots are medium-sized water birds that are members of the rail family, Rallidae. They constitute the genus ''Fulica'', the name being the Latin term for "coot". Coots have predominantly black plumage, and—unlike many rails—they are usual ...

s. Despite being a nature sanctuary for the country of Chile under the National Monuments Act, it wasn't internationally recognized for its cultural and natural value until the Ramsar Wetlands Convention of 1971. The Carlos Anwandter Nature Sanctuary Management Plan was instated in 2016 by the

National Forest Corporation The National Forest Corporation or CONAF (Corporación Nacional Forestal) is a Chilean State-owned private non-profit organization, through which the Chilean state contributes to the development and sustainable management of the country's forest ...

(CONAF) with financial aid from the Ramsar Convention. The invasive plant species ''

Limnobium laevigatum ''Hydrocharis laevigata'' is a floating aquatic plant, and is a member of the family Hydrocharitaceae. Common names include West Indian spongeplant, South American spongeplant and Amazon or smooth frogbit. This plant was introduced to North Ameri ...

'' is present in the sanctuary.

Black-necked swan population

2004 pollution controversy

In 2004, the Valdivia Pulp Mill was established in

San José de la Mariquina Mariquina is a commune in southern Chile, Valdivia Province, Los Ríos Region. It is located about 40 km northeast of Valdivia, close to Cruces River. The capital is the city of San José de la Mariquina. The commune's main economic activ ...

, located 25 km (16 mi) northeast of the preserve near the Cruces River. As a result, the iconic black-necked swans began to experience mortality and migration issues. The population initially decreased from approximately five thousand to 942 in January 2005 and further plummeted to 291 by July 2005. During the same year, ecologists and academic staff from the

Austral University of Chile Austral University of Chile ( or UACh) is a Chilean research university based primarily in Valdivia, with satellite campuses in Puerto Montt and Coyhaique. Founded on September 7, 1954, it is one of the eight original Chilean Traditional Universi ...

in Valdivia accused the forestry enterprise Celulosa Arauco y Constitución (CELCO) of polluting the river. Autopsies conducted on the swans revealed that their deaths were caused by elevated levels of iron and hazardous metals in the water. Consequently, the pulp mill was forced to shut down while the case underwent investigation. Even in 2006, the Latin American water tribunal recommended the permanent closure of the mill. Meanwhile, alternative hypotheses have been proposed to explain the significant decline in the swan population. CELCO was ultimately condemned in court in 2013. The ruling mandated CELCO to pay an indemnity of 2,600 million

Chilean pesos The peso is the currency of Chile. The current peso has circulated since 1975, with a previous version circulating between 1817 and 1960. Its symbol is defined as a letter S with either one or two vertical bars superimposed prefixing the amoun ...

to the state, in addition to another 2,600 million for the implementation of community development programs. CELCO chose not to appeal the ruling. Between 2005 and 2011, the swan population did not exceed a count slightly above 500 individuals. However, by 2014, the population had recovered to over 3,600 individuals, still approximately 1,500 birds fewer than before the pulp mill's establishment.

Changes after 2014

In April 2020, a record-breaking count of 21,123 black-necked swans was recorded in the sanctuary. In June 2022, the

(Conaf) noticed a sharp decline in the swan population within the sanctuary, dropping from 22,419 in 2020 to 2,782. No nests or eggs were found during the surveys conducted by the Conaf. The proliferation of

American mink The American mink (''Neogale vison'') is a semiaquatic species of Mustelidae, mustelid native to North America, though human introduction has expanded its range to many parts of Europe, Asia, and South America. Because of range expansion, the Am ...

s and the incursion of

South American sea lion The South American sea lion (''Otaria flavescens'', formerly ''Otaria byronia''), also called the southern sea lion and the Patagonian sea lion, is a sea lion found on the western and southeastern coasts of South America. It is the Monotypic ta ...

s into the sanctuary are believed to have adversely affected the swan populations. Furthermore, the use of water scooters and the development of real estate projects around the sanctuary have also been suggested as negative influences on the swan population. In March 2023, several cases of

avian influenza Avian influenza, also known as avian flu or bird flu, is a disease caused by the influenza A virus, which primarily affects birds but can sometimes affect mammals including humans. Wild aquatic birds are the primary host of the influenza A viru ...

were detected in the black-necked swan populations within the sanctuary, prompting authorities to declare a "zoosanitary emergency."

References

Protected areas of Los Ríos Region Ramsar sites in Chile Nature sanctuaries of Chile Urban wetlands of Chile Birdwatching sites in Chile Valdivian temperate forests 1981 establishments in Chile Protected areas established in 1981 {{SouthAm-protected-area-stub

Black-necked swan population

2004 pollution controversy

Changes after 2014

See also

References