Conservation news

In Madagascar’s capital, pollution threatens an oasis for birds

  • Tsarasaotra Park, located in the center of Antananarivo, is one of the few remaining refuges for the waterbirds of Madagascar’s highlands.
  • The park is the first private site to be classified as a wetland of international importance by the Ramsar Convention.
  • The fast pace of urbanization in the capital is degrading the park’s biodiversity and putting the birds at risk.

ANTANANARIVO, Madagascar — Four kilometers (2.5 miles) from downtown Antananarivo, Tsarasaotra Park has long been an oasis of calm in Madagascar’s capital city. It is the first private site to be designated as a wetland of international importance by the Ramsar Convention. However, the expansion of the capital, with its 1.6 million residents, poses a serious threat to the park and its birds.

At the end of the 19th century, a nature-loving Malagasy industrialist named Emile Ranarivelo bought the walled property from a grandson of one of Queen Ranavalona III’s prime ministers. The Ranarivelo family still owns and manages the park, which is a popular birdwatching site for birders and ornithologists from around the world.

This 27-hectare (66-acre) green oasis nestled in the city is one of the few remaining refuges for the waterbirds of Madagascar’s highlands. The site includes two lakes, small islands and a small eucalyptus forest, and hosts 49 species of birds. Some have taken up residence there while some migrating birds just pass through or stop in to breed.

From left: Cattle egret (Bubulcus ibis), Malagasy pond heron (Ardeola idae), Humblot’s heron (Ardea humbloti), also known as the Madagascar heron. Image by Herinjaka Rakotomamonjy.

Species such as the Madagascan wagtail (Motacilla flaviventris), which is endemic to Madagascar, and the Malagasy pond heron (Ardeola idae), which is endangered, have found refuge there. Believing that the Malagasy pond heron hadn’t returned to the region to breed for several years, scientists were very surprised to have found these birds in the park, according to site administrator Jean-Yves Ranarivelo, who goes by Joda. “We are very proud to be able to protect them,” he said. The Malagasy pond heron breeds only in Madagascar and on the islands of Europa and Aldabra.

The park is also one of the only places in Madagascar where you can observe dimorphic egrets (Egretta dimorpha) and cattle egrets (Bubulcus ibis) trampling the ground. You can also see more than 100 pairs of great egrets (Ardea alba) nesting on top of the eucalyptus trees.

Located in the heart of Antananarivo’s strategic and economic zone, along the Ankorondrano-Soavimasoandro axis route, the park does not escape the frenzy of the capital. Thousands of bumper-to-bumper motorists pass right by its walls every day to access the busy shops in the neighborhood. At peak times, it can take more than an hour to travel this 3-km (1.9-mi) route.

City air becomes increasingly difficult to breathe

Antananarivo records very high levels of air pollution. According to the Initiative for Development, Ecological Restoration and Innovation (INDRI), a Malagasy think-and-do-tank, coarse particles known as PM10 can get to concentrations of 157 micrograms per cubic meter, which is well above the limits of 20 micrograms per cubic meter recommended by the World Health Organization (WHO).

A flock of Meller’s ducks (Anas melleri) on the lake surrounded by sub-humid forest. Image by Herinjaka Rakotomamonjy.
In the foreground, a swarm of Meller’s ducks (Anas melleri). In the background, from left: Madagascan wagtail (Motacilla flaviventris), cattle egret (Bubulcus ibis). Image by Herinjaka Rakotomamonjy.

Air pollution is so severe that a layer of thick smog hovers over the city. “The smoke from cars and industry darkens the leaves of our trees,” said Ranarivelo said. “It is detrimental to the welfare and health of the birds. If you go deeper into the park, the trees are cleaner and the birds are better protected. But this protection is precarious.”

In fact, the particulate matter released by car traffic is harmful to all living beings. UNICEF estimates that more than 20% of deaths in Madagascar are caused by exposure to pollution. “Birds also breathe this air loaded with toxic particles,” said Félix Razafindrajao, waterbirds manager at the Durrell Wildlife Conservation Trust, an NGO. “It is quite possible that their health is also affected.”

Plastic wreaks havoc

The park is located in the center of a basin surrounded by several urban districts. Wastewater from nearby homes, loaded with plastic and other harmful substances, flows into the lake, despite the filters installed by the park. “Some passersby secretly and deliberately dump their rubbish here. In the neighborhood, they even destroy the filters so their dirty water flows everywhere,” Ranarivelo said.

Plastic is a serious threat to birds. Studies have shown that plastic can kill birds who ingest it because it makes them feel full and stop eating.

The main lake in Tsarasaotra Park and its island. Image by Herinjaka Rakotomamonjy.

In general, a park’s buffer zone protects its interior, which provides food for the animals. Tsarasaotra Park is almost devoid of a buffer zone. This forces the birds to leave to feed. “The invertebrates and crustaceans that birds feed on will disappear if the lake is polluted with chemicals,” said Razafindrajao said. Lake animals are very sensitive to changes in acidity.

“Our birds have to fly and hunt in rice fields and ponds outside the park or on the outskirts of the city,” Ranarivelo said. “With increasing urbanization and backfilling, we don’t know where or how they will manage to feed later.”

The water filtration system in Tsarasaotra Park. Image by Herinjaka Rakotomamonjy.
Jean-Yves Ranarivelo, administrator of Tsarasaotra Park. Image by Herinjaka Rakotomamonjy.

The birds can no longer hear themselves sing

The city’s noise pollution also impacts the health of humans and animals. In birds, noise can cause reproductive disorders and greater vulnerability to predators.

“In our neighborhood, the Soavimasoandro church rings the bells from 5:20 a.m., before sunrise,” Ranarivelo said. “It wakes up the birds in the park too early. The birds’ sleep cycles are disturbed, and they can no longer hear themselves singing because of the noise pollution.”

“The city vibrations can also affect bird behavior,” Razafindrajao said. “It can push them to migrate. It is quite possible that it also affects their reproductive capacity.”

To the despair of Malagasy nature lovers, Antananarivo’s development is contributing daily to the deterioration of Tsarasaotra Park’s unique ecosystem. Ranarivelo said he has high hopes of preserving it. He does everything he can to make the water filtration systems more efficient, to replant the eucalyptus that birds take shelter in, and to collaborate with the neighborhood so that nature and the city can simply coexist.

[Photo] Two dimorphic egrets (Egretta dimorpha), one with dark plumage and the other with white plumage, photographed on the island of Nosy Ve, in southwest Madagascar. Image by Charles J. Sharp via Wikimedia Commons (CC BY-SA 4.0).

Banner image: The Madagascan wagtail (Motacilla flaviventris), endemic to Madagascar, frequents Tsarasaotra Park. Image by Heinonlein via Wikimedia Commons (CC BY-SA 4.0).

 

This article was first published on Mongabay Français on May 26, 2020.