The 12,000-acre Caroni Swamp is not only one of Trinidad’s most renowned tourist attractions and home to our national bird, the Scarlet Ibis, but it is essential in helping our twin island republic fight the devastating effects of global warming.
It is feared that if this habitat is destroyed, the Ibis will migrate to breed and leave T&T altogether. In addition, our fragile ecosystem needs all the help it can get since this country is considered the Caribbean’s largest producer of carbon dioxide (CO2) emissions because of our large industrial plants.
According to the Institute of Marine Affairs (IMA) deputy director and wetlands expert Dr Rahanna Juman, between 1994 and 2014 almost 50 acres of the Caroni mangrove have been washed away by coastal erosion.
If a more pronounced effort is not made to take care of this wetland, one of three protected under the 1975 Ramsar Convention, Juman believes the mangroves could suffer from “coastal squeeze”.
Coastal squeeze causes the mangroves to die because they are caught between coastal erosion and man-made development.
In the second part of this Guardian Media special report on the effects of global warming on T&T’s ecosystem, a news team visited the Caroni Bird Sanctuary, accommodated by Juman and Navin Kalpoo of the Kalpoo Brothers’ Tours.
The Caroni wetlands are home to over 150 species of birds, including the Ibis and serves as a nursery for dozens of species of fish and shellfish. Most recently, pink Flamingos have been migrating to the mangroves from South America to feed.
But it’s not all beauty and breeze at the sanctuary as the black, red and white mangrove that the birds, fishes, and shellfish depend on is being eroded by the waters of the Gulf of Paria.
Juman said human intervention into the natural watercourses over the years has led to mangrove dieback.
“The Caroni River is a huge river and about 11 different rivers flow into it from as far as Valencia to San Juan. And over the years what was done for flood mitigation was to deepen and widen the Caroni River and every time they dredge it, they put the sediment on the embankment, so they have diked it. What would have normally flowed into the swamp itself, is now going straight out into the Gulf of Paria,” Juman said.
“Because they have diked it and it is not getting that fresh water or that tidal flow, you have mangrove dieback because conditions have become so salty or what you call hyper-saline. Seawater is normally 35 parts per thousand and if it goes up to 90 parts per thousand, you will have the mangroves dying."
The reason the mangroves die without access to both fresh and salt water is that the trees depend on the sediment brought by the river to create mud banks that the trees can colonise.
“In the Caroni River, you have a lot of sediments coming out and being deposited along the shoreline. Here you don’t have that, so what you find between this river and the Madame Espangol River is that we’ve had a lot of mangrove being eroded. We have estimated between 1994 and 2014, over a long period of time, about 20 hectares have been lost due to erosion. Out here there is a concern that because there is no new sediment coming into the area, then you would have some more erosion occurring.”
But Juman said new mangrove trees are growing in areas like Brickfield and Felicity, where there are multiple mud banks created by sediment. This gives hope that some of the CO2 that T&T produces can be absorbed by the mangrove.
“Mangroves, in particular, are seen as very helpful with regards to us mitigating against the effects of climate change because they act as a sink for carbon dioxide, they sequester or they suck in CO2 and as you know, part of the reason for global warming is the CO2 that is in our atmosphere that we produce from our industrial activities, so mangroves have the potential to store a lot of this CO2 in their biomass and in their soil and in that way they help with regards to climate change mitigation.”
In addition to sinking the CO2, mangroves can also help mitigate the effects of the rising sea level with their spreading roots.
“More importantly, mangroves also assist us in adapting to the impacts of climate change especially since we live on a small island developing state and we have very little space, our coast is very important and mangrove, because of their structure, with the roots, they help to break down the velocity of the wave action so they tend to protect us against coastal erosion and the trees act as a windbreak so they act in regards to storm protection.”
She explained that as the sea water continues to encroach on the land, the mangrove will follow it but this can cause a coastal squeeze.
“As the sea level rises and water goes inland, mangroves will continue to grow inward with the sea water, however, if there is a building development or a highway that prevents the mangrove from actually growing on the land, you are going to have a situation known as coastal squeeze, where you are going to lose all your mangroves and all the functions they provide.”
Red tape ties up boundary extension
Dr Juman told the Sunday Guardian the currently protected area boundary as defined by the Forestry Act and Conservation of Wildlife Act was established to protect the Scarlet Ibis'nesting sites. But she said the Ibis are now nesting further inland, away from the protected area.
“The IMA sits on a stakeholder committee under the Improving Forestry and Protected Areas Management in T&T project (IFPAM). Under this project, they are developing a Management Plan for Caroni Swamp and consideration has to be given to extend the boundary of the protected area landward to protect Scarlet Ibis nesting sites,” Juman said.
But red tape with land acquisition needed for the extension is where the process comes to a screeching halt.
“However, some of the land are private holdings so much discussion/legal consideration must be had on this matter and this has not started,” Juman said
Kalpoo: Ibis will leave the sanctuary
Navin Kalpoo grew up in the Caroni swamplands, accompanying his father and grandfather as they took visitors on tours throughout the wetlands to see the stunning Scarlet Ibis as they come to roost and breed.
Kalpoo and his brother Ravi followed their father into business and today they are one of the most well-known tour operators in the sanctuary.
He can point out any type of bird, flora or fauna and is able to skillfully navigate his boat along the sides of the mangrove to give visitors a closer look of the snakes that nestle in the branches over the water sunning themselves after large meals.
Kalpoo described the changes he has seen in the swamp over the years.
“I have seen areas that were marshes being overgrown by mangrove and areas that were land are being covered up. We have seen over the years the Scarlet Ibis used to be miles into the reserve area and over the years as the conditions are changing and the birds are moving further inland, closer to private property.”
The Scarlet Ibis is an Environmentally Sensitive Species and from July 2018 the law stated that being in possession of even a feather of the bird can result in you being fined $100,000 and imprisoned for two years.
Although Kalpoo said the increased fine does have a deterrent effect on poachers, he is worried that if the mangroves continue to move inland, the birds will move with them.
“When they are in the sanctuary, we have a watchful eye over them here but in the future, we have to take another look at our boundaries and reserve areas because they will be going out into private land and we don’t want that.”
He is also worried that if the mangrove continues to erode, the Ibis may leave the swamp altogether.
“If nothing is done soon, the Scarlet Ibis may not stay here because when the conditions for them are poor, they migrate to Venezuela to have their young, so we can have a national bird that no longer wants to live in the Caroni Swamp.”
Kalpoo said he often assists the Forestry Division in their thrice-yearly count of the Ibis. At the last count, he said the birds numbered between 16,000 to 18,000.
Mangrove dieback in Australia
Between 2015 and 2016, Northern Australia lost 8,000 hectares (19768.43 acres) of its mangrove in one of the world’s worst instances of mangrove dieback.
The dieback was blamed on extreme temperatures, drought and lowered sea levels. It was first noticed by tour operators who reported seeing skeletonised mangroves over several hundred kilometres. They reported the trees seemed to have died simultaneously.
In October 2018, scientists at the James Cook University visited the mangrove but their report was grim.
“While there has been limited resprouting with seedling establishment and regrowth, the recovery looks like it’s being overwhelmed by erosion combined with physical scouring by masses of drift logs and branches from dead mangroves. Each high tide, dead material scrapes across the seedlings, breaking and killing them.”
Head of the team, Dr Norman Duke labelled the incident as the worse instance of climate-related dieback of mangroves ever reported.
“Essentially, they died of thirst,” he said.
Several key stakeholders are now involved in a series of studies in the affected area to formulate best-practice plans for the future.
The Ramsar Convention
In 1971, in Iran, the Ramsar Convention was adopted and since then, over 90 per cent of United Nations member states have signed on. T&T signed on in April, 1993. There are three Ramsar sites across the country—the Caroni Swamp, the Nariva Swamp and the Buccoo Reef/Bon Accord Lagoon Complex. T&T has 15,919 hectares (39336.7 acres) of wetlands.
The Ramsar Convention’s mission is the “the conservation and wise use of all wetlands through local and national actions and international cooperation, as a contribution towards achieving sustainable development throughout the world”.
The convention recognises the importance of wetlands and also their destruction for man-made developments.
There are three pillars that each contracting State has agreed to:
•to work towards the wise use of all their wetlands
•to designate suitable wetlands for the list of Wetlands of International Importance (the “Ramsar List”) and ensure their effective management
•to cooperate internationally on transboundary wetlands/s.
The United Nations Environment Programme (UN Environment) lists two types of conservation for mangrove wetlands.
The first and most common, is declaring mangroves protected, therefore limiting the effects of human activity.
The second is to replant and replenish the mangroves. But UN Environment warns that if replanting is the method being used, that stakeholders must first address issues that caused the mangrove to die before any replanting can be done.
Planting is often used as a restoration technique, although, mangrove restoration can occur naturally in 15-30 years if the tidal hydrology of the site is not disrupted and if there is a good supply of waterborne seeds or seedlings. Successful restoration requires an understanding of the causes of mangrove loss. If the causes are not addressed, then re-establishment may not be effective. This is particularly important if one of the causes is hydrological change.
The following five steps were taken from a manual published in 2006 by the Mangrove Action Project in Indonesia.
5 critical steps for mangrove restoration
1. Understand the autecology (individual species ecology) of the mangrove species at the site; in particular the patterns of reproduction, propagule distribution, and successful seedling establishment.
2. Understand the normal hydrologic patterns that control the distribution and successful establishment and growth of targeted mangrove species.
3. Assess modifications of the original mangrove environment that currently prevent natural secondary succession (recovery after damage).
4. Design the restoration programme to restore appropriate hydrology and, if possible, utilise natural volunteer mangrove propagule recruitment for plant establishment.
5. Only utilise actual planting of propagules, collected seedlings, or cultivated seedlings after determining (through steps a-d) that natural recruitment will not provide the quantity of successfully established seedlings, rate of stabilisation, or rate of growth of saplings established as objectives for the restoration project.