Trinidad’s Caroni Swamp is ever-evolving

It is home to the Scarlet Ibis, one Trinidad and Tobago's national birds

Originally published on Global Voices

By Jeniece Germain

This story was first published on the Cari-Bois Environmental News Network. An edited version appears below as part of a content-sharing agreement.

The Caroni Swamp, located on Trinidad's western coast, is the largest mangrove wetland in the country. It is a rich ecosystem that comprises a network of waterways, lagoons, and mangrove forests that cover about 5,996 hectares. The swamp is best known for being the habitat of the Scarlet Ibis, one of Trinidad and Tobago's two national birds, and it is recognised as an important wetland under the Ramsar Convention.

Home to many other species, including egrets, herons, caimans, snakes, crabs, and fish, the swamp's diverse ecosystem is vital for protecting the coast from erosion and for providing a home for many of Trinidad’s wildlife species. Tourists and locals visit the swamp for birdwatching boat tours, especially to catch a glimpse of the Scarlet Ibis coming home to roost in the evenings.

Flamingoes join the swamp community

Over the past eight years, however, local conservation officials have observed an increase in the number of flamingos at the swamp. We spoke with representatives of the Forestry Division’s Wildlife Section and Nanan’s Eco Tours to learn about some of the changes that have been happening within the swamp and understand the impact they have on both biodiversity and conservation.

Tevin Butler, a wildlife research assistant at the Forestry Division, said flamingos have been observed at the swamp since the 1980s, but the current population is higher than average: “While their numbers remained around 100 in previous decades, recent surveys by the Division have reported approximately 600 birds.”

Of the six species of flamingo in existence, the Caribbean Flamingo, which can be found from Venezuela to Florida, calls the Caroni Swamp home.

While non-migratory in nature, flamingos are known to fly long distances in search of food or to reproduce, and, like the Scarlet Ibis, they obtain their colour from consuming carotenoid-rich food like shrimp and crabs found in the coastal mudflats of the swamp.

Butler believes the relatively “sudden rise” in the number of flamingos at Caroni might be due to disturbances of their previous habitats in neighbouring territories. As a result, they may have “moved” to Trinidad for new feeding and breeding grounds, but Butler is careful to note that the root causes of the uptick in their population remain unknown.

Although this increase in their population is a good sign, balance within ecosystems is important. Some may question if the increase in flamingos has affected any other species at the swamp through competition for food and resources.

Tour guide Khemraj Bhagan said the flamingos exist harmoniously in the swamp, especially with its “famous” neighbour, the Scarlet Ibis. He explained that the Ibis roost in the foliage of the mangroves, while flamingos remain on the mud flats where they feed and sleep.

A new mussel in the swamp

There have been other changes, as well. While the increase in flamingos has been welcomed, the growing presence of mussels at the swamp has been received with less fanfare.

Bhagan confirmed that a species of small, black mussel has been rapidly multiplying on the roots of the swamp’s red mangroves, and registered his concern over the possibility of these molluscs “taking over the oysters.”

The Crassostrea rhizophorae, more commonly known as the mangrove cupped oyster, a popular local street food, is found in the swamp. The mussel in question is the Mytella strigata or charru mussel, which has been observed in the neighbouring Gulf of Paria since the 1950s. Whether their increasing numbers pose a threat to the oyster fishery or, by extension, the swamp needs to be further researched.

Impact of the pandemic

The reduction in human activity in the swamp during the COVID-19 pandemic was thought by many to offer nature a well-deserved break from man-driven actions, but recent studies revealed that this anthropause had a double-sided effect on species conservation.

While some species at the Caroni Swamp benefitted from limited disturbance, others may have suffered from the lack of human protection, the Caiman crocodilus or spectacled caiman being among the latter.

Director of Nanan’s Eco Tours, Victor Nanan, has observed what he considers to be a significant decline in spectacled caiman sightings. Before the pandemic, Nanan said tour guides may have seen one to two caimans per week. However, since the recommencement of tours in 2022, their sightings have been limited.

As top predators, caimans are vital in regulating the populations of prey. If they do not fulfil this role, an overabundance of prey species can put pressure on resources within an ecosystem.

Nanan posited that the decline in spectacled caimans at Caroni Swamp was likely due to increased poaching during pandemic lockdowns. Poaching, especially of the Scarlet Ibis for meat during the Christmas season, is an ongoing problem which he believes needs to be addressed through more swamp patrols and greater enforcement of environmental laws.

Effects of a 2022 oil spill

In August 2022, a truck accidentally spilled diesel near the Caroni Swamp, an incident which Nanan said contributed to mangrove die-off along the swamp’s entry channel.

While the authorities made efforts to clean the spill, the fuel could not be adequately contained, and made its way into the entry channel, causing the die-off.

Little more than two years have passed since the spill, and Nanan claims you can still see an oil slick on the water’s surface after torrential rainfall. Although a preliminary investigation was conducted, Nanan alleged that no follow-up inspections have been made.

The spill, he said, did not affect the number of visitors to the swamp.

The Caroni boardwalk

To commemorate this year’s World Wetlands Day on February 2, the Ministry of Agriculture, Land and Fisheries formally opened the Caroni Boardwalk. Free of charge to the public, the boardwalk extends into the swamp, giving visitors a waterfront view of its many natural attractions, including the Scarlet Ibis.

At the opening, the ministry’s Permanent Secretary Farook Hosein explained that the boardwalk was created to allow for greater accessibility to the swamp, especially for those unable to participate in boat tours. Visitors are permitted on the boardwalk for only 10 minutes at a time, so there is some degree of regulation in this regard.

The Forestry Division's Conservator of Forests, Denny Dipchansingh, said that the Public Sector Investment Programme has already approved plans to expand the boardwalk. There are also plans to restore the birdwatching tower at the swamp, all in an effort to “deepen the public’s connection with nature and underscore the importance of wetlands to human well-being.”

Written by Cari-Bois News