35 years ago, on a World Environment Day, the City’s Deliberative Council named and officially recognized a natural area that made its way on its own just a couple of kilometers from the Casa Rosada: the Costanera Sur Ecological Reserve.
The Reserve is an oasis of biodiversity among the cement. At different times, it was seen 575 species of plants, 307 of birds, 18 of mammals, 28 of reptiles and 22 of fish.
A survey carried out between April 2020 and April 2021 by the Technical Team for Biodiversity Conservation of the Buenos Aires Ministry of the Environment, discovered 61 species that, at least in the City, can only be seen in Costanera Sur. Like different types of owls, including the small caburé and the red burrito. Or the sirirí duck or the snail bird, known that way because it feeds on snails.
The property was declared a Natural Park and Costanera Sur Ecological Reserve Zone on June 5, 1986.
In one year, this team dependent on the Operational Management of Ecological Reserves and Conservation Areas, also surveyed the biodiversity of the Lake Lugano Ecological Reserve, of the Sarmiento Park reservoirs and the Carlos Thays Botanical Garden. With Costanera Sur, there are four bio-corridors that allow species to move around the City.
111 samplings were made to inventory 5 taxonomic groups: vegetation, birds, reptiles, butterflies and mammals. In total, they found 415 kinds of birds; Butterflies 59; 10 species of mammals and reptiles and 890 varieties of plants.
Among those species there are migratory birds, such as the brown swallow, the churrinche, the striped benteveo, the peregrine falcon and the lobster harrier. Y butterflies like the Argentine flag, the little mirrors, the monarch, the stained lady and the Mexican passionflower.
The monarch butterfly is one of the species that can be found in the City. Photo Rubén Digilio
Among the mammals, nutria, sheep weasels, guinea pigs and capybaras were found.
In the case of Lake Lugano, there are 6 species of its own, among which are the bell lettuce, the black-headed duck and the bare-faced raven. And in Parque Sarmiento, one. It is the white-browed swallow. Among the four parks surveyed, there are 38 species in common.
The nutria is one of the mammals that are usually found in the Costanera Sur Ecological Reserve, among other parts of the City.
The Ecological Reserve that was born among the rubble
On September 11, 1918, in a previously abandoned strip of the Río de la Plata, it was inaugurated the seaside resort of Costanera Sur. With its boulevard, stairway to the river, gazebos and lanterns and gardens, it soon became one of the city’s favorite walks. Its splendor lasted until the 1960s.
But the water became more and more polluted and was no longer safe for bathers. The area deteriorated until, in 1972, the idea of winning land from the river in front of the spa came up to build an “Administrative Center”.
The Costanera Sur spa, around the 70s.
In the manner of the Dutch polders, embankments were made with rubble of the demolitions to expand the 9 de Julio highway and to build the 25 de Mayo highway. And the spaces were filled with sediments from the Río de la Plata.
In 1978, the lands were transferred to the City. The administrative center project came to nothing, although the unloading of materials continued until 1984. The place, no longer destined, became the ideal breeding ground for nature to make its way.
With the sediment and the debris seeds had arrived. Vegetation began to grow and animals appeared. Thus, just four blocks from the center of Buenos Aires, a typical landscape of the delta and the riverbank of the River Plate was formed, similar to the one that existed before colonization.
With the sediment from the river fill, seeds arrived. Vegetation grew and various animal species arrived. Photo Germán García Adrasti
People discovered this microclimate long before officials. The Friends of the Earth, Wildlife and Argentine Birds Association began to work so that the authorities of the City to be a protected area. By then, they organized guided tours to raise awareness about the richness and biodiversity of the area.
Official recognition arrived June 5, 1986, when the then Deliberative Council approved an ordinance declaring the property Natural Park and Ecological Reserve Zone. It was the first protected area of the City.
In 2005, it was also declared as “Ramsar Site” by the Convention dedicated to the conservation of the world’s wetlands.
The Costanera Sur Ecological Reserve was declared a Ramsar Site for its wetlands. Photo Germán García Adrasti
Today it has 350 hectares with four lagoons, a native species nursery, a wildlife rescue center and an Interpretation Center. There is also a beach, although bathing in the river is prohibited.
Among the resistance generated in some real estate sectors that the City “gave away” valuable land to nature and the neglect, the Reserve suffered more than 500 fires in all these years.
Since 2018, a thermal camera system has been warning of possible outbreaks. And in the event of an alarm, it is activated immediately, with the intervention of volunteer firefighters, the City and a forestry brigade belonging to the Reserve.
Smoke floats over the Costanera Sur Ecological Reserve, during a fire in January 2020. Photo Télam
The biodiversity of the Costanera Sur Reserve
In the Reserve there are three ecoregions: Pampas, spinal and delta grasslands.
According to the report of the Buenos Aires Secretary of the Environment, among the 575 plant species In the Reserve there are plumerillos, Creole willows and river alders, ceibos, cattails and reeds.
They can also be seen 307 species of birds like the benteveo, the chingolo and the barillero and other larger ones like the carancho, the chimango, the chajá and the hawk.
Bird watching in the Ecological Reserve. Jacana or cock of water. They walk on aquatic plants. Photo: Simón Tagtachian. www.coarecs.com.ar
During the history of the Costanera Sur Ecological Reserve, there have also been sighted 18 species of mammals among which are the opossum, the bat and even the fur sea lion. There are also rodents such as the nutria, the cuis and the mouse. Although not all these animals were found in the last survey.
Lagoon turtles, long-necked turtles and painted turtles move among the reeds. Also, lizards and snakes. In total they have been found 28 species of reptiles.
Ecological Reserve. Overo lizard. It comes out in spring and summer. The rest of the year it hibernates. Photo: Simón Tagtachian.
There is also 22 species of fish, from mojarras to dorados, and 12 amphibians.
“For many residents, the Costanera Sur Ecological Reserve is a place for a walk. But also, plays a fundamental role in conservation and preservation of birds, insects and plants. Our specialists and technicians are dedicated to caring for and promoting this biodiversity, ”says Eduardo Macchiavelli, the City’s Secretary of the Environment.
The Costanera Sur Ecological Reserve can be visited from Tuesday to Sunday from 9 a.m. to 6 p.m.
Bird watching in the Ecological Reserve. Red nose. It is in the Reserve all year round. It is a heron and it feeds on fish and the Creole eel. Photo: Simón Tagtachian
Lake Lugano, the ecological reserve of southern Buenos Aires
In an old meander of the Riachuelo another ecological reserve was developed: that of the Lake lugano. There are 36 hectares around this water mirror and the coast of Arroyo Cildáñez, in Villa Soldati.
The Lake Lugano Reserve covers 36 hectares.
Native vegetation developed in that area, such as the Orchid of the Talar, which grows on the banks of the lake and Cildáñez. Declared a Symbolic Flower of the City of Buenos Aires, it reappeared in this area of southern Buenos Aires after years without being seen in the Buenos Aires area.
In total, in this reserve there are 130 species of birds, 14 of butterflies, 2 of mammals, 3 of reptiles and 299 of plants.
The Lake Lugano Ecological Reserve can be visited from Tuesday to Friday, from 10 a.m. to 2 p.m.
The Lugano Lake Ecological Reserve is open to the public from Tuesday to Friday, from 10am to 2pm.
The Sarmiento Park reservoirs, the solution to the floods that attracted life
The Carau, Carpenter, Cardinal and Swan reservoirs They were built in 2014 in Parque Sarmiento. Its objective was to mitigate the floods in the neighborhoods of Saavedra, Núñez, Belgrano and Villa Ortúzar. With a capacity of up to 250,000 cubic meters, they serve to retain excess water from heavy rains and contain the spill of the Medrano stream.
The construction of the reservoirs in Sarmiento Park, in 2014. Photo Germán García Adrasti
But these four reservoirs, which cover some 8.5 hectares of surface, had an unintended role. They attracted life. That is why the area also it was declared an ecological reserve.
The Sarmiento Park reservoir area was also declared an ecological reserve.
There are 40 species of birds, such as mule ducks, herons, and macaws. And reptiles like lizards overos. In the official survey it was found that only in this area can white-browed swallows be sighted.