Are we doing enough to conserve them?

By Ewa Krzyszczyk, School for Field Studies Center for Marine Resource Studies

When you think of mangroves, do you imagine blue skies, crystal clear water, lush green forest, dragonflies silently gliding above, the songs of the mangrove cuckoos? No? You might want to honor them a visit.

In her article, “The Magic of Mangroves,” (Fall 2019 Times of the Islands), Kelly Currington describes an enchanting trip through a mangrove forest: “We move through the forests, the sound of birds chirping and leaves rustling is a calm and peaceful sound . . . there is something incredibly spiritual and magical about gliding through them.” Unfortunately, we do not often view these coastal forests as “beautiful by nature” or an attraction for tourists and locals alike. In fact, they are most often viewed as wastelands or unhealthy environments. The poor mighty mangrove is terribly misunderstood.

The mighty mangrove holds great value to both humans and the natural world.

Mangroves hold great value to both humans and the natural world, as they provide important goods and services that play a critical role in supporting our well-being. Mangroves form a natural dense barrier against extreme weather events and disasters, which reduces the loss of property and vulnerability of local communities. Mangroves aid in stabilizing shores by trapping sediments and building land, thus protecting coastlines from erosion. Mangroves also help to improve water quality by filtering out nutrients and sediments and absorbing massive amounts of carbon from the atmosphere.

On average, mangroves store around 1,000 tonnes of carbon per hectare in their biomass and underlying soil, making them some of the most carbon-rich ecosystems on the planet. And yet mangrove forests also support a bewildering array of organisms, from sponges, tiny snails, and algae (such as mermaid’s wine glass), to reef fish such as parrotfish, grouper and sharks, including endangered and protected species. Not only are mangroves considered vital nursery grounds for a large range of marine species, but they also enhance the biomass of several commercially important fish on neighboring reefs, consequently providing us with an ample supply of food.

Mangroves are among the most productive, biologically complex and important ecosystems on Earth, and yet they are one of the world’s most threatened tropical ecosystems. Mangroves are being destroyed at rates three to five times greater than the average rates of forest loss and over a quarter of the original mangrove cover around the world has already disappeared.

This aerial photo shows the extensive mangrove forests in South Caicos.

The Turks & Caicos Islands are fortunate to have extensive mangrove forests along their 389 kilometers of coastline. The western coastline of the 8.2 square mile island of South Caicos is particularly abundant with mangroves, so much that the TCI Government proposed to designate them as a Wetland Critical Habitat Reserve in 2016. Yet it cannot go unnoticed that the mangrove-rich coastline is also home to the island’s airport, dump and fish processing plant. These human facilities are well-situated for their protection from extreme weather events, but how much of an impact are they having on their surrounding mangrove habitat?

Living at the edge of land and sea, mangroves are well adapted to deal with natural stressors, but they are particularly sensitive to environmental disturbances created by human activities, such as sewage disposal, airports and oil spills.
The over-reliance on open dump and landfill systems for solid waste management has proven to be a significant environmental problem. Waste contaminants leach into the surrounding soil which then serves as a sink, persisting for many years and further leaching into the surrounding waters. Airports pollute our air with noxious chemicals such as sulphur dioxide and nitrogen oxide, and jet fuel exhaust causes particulates to settle and accumulate in the soil and sediments surrounding the airport. These various pollutants can be transferred to humans via their gradual accumulation in water and sediment (bioaccumulation) and the increasing concentration from organism to organism moving up a food chain. This means that the higher the organism is on the food chain, the higher the load of toxic chemicals (biomagnification).

In order to better understand the health and function of mangrove ecosystems in relation to human activity, many avenues of research are possible and useful. At The School for Field Studies’ Center for Marine Resource Studies (SFS CMRS) on South Caicos, we have been conducting research to understand how apex predators such as sharks and rays utilize our local mangrove ecosystems.

Sharks and rays are considered keystone species, meaning they play a crucial role in maintaining the structure and integrity of an ecosystem and are an indicator for the health of an ecosystem. Using baby Baited Remote Underwater Videos (BRUVs), which consist of a weighted- down camera and bait (local fish) attached to PVC piping, we found that lemon sharks, nurse sharks, barracuda, and southern stingrays were in higher abundance near the mangroves around the airport when compared to near the dump or fishing plant.

These results provide important insights into the current health status of our local mangroves and are also useful baseline knowledge for any future disturbances. The airport, dump and fishing plant are well situated within these mangroves, which will help protect them from storms and hurricanes, but without proper care and management of these facilities, the mangroves are vulnerable to pollution and degradation. The consequences of any potential future mangrove decline would be particularly severe for the well-being of our coastal community.

Marjorie Basden High School students kayaked in their local mangroves on South Caicos to learn the significance of this unique and vital ecosystem.

The loss of mangroves is a loss for humans—storm protection will be lost and fishery resources will be destroyed. Once lost, mangrove forests are very difficult and costly to restore. It is therefore imperative that we protect what we have.
In order to protect these “beautiful by nature” mangroves, we need to educate each other, and it all begins with our youth. Together, SFS CMRS and Ms. Felix at the Marjorie Basden High School on South Caicos have reignited the school’s science club. Groups of students are taken kayaking through our local mangroves, where they learn how to perform scientific research, discover the importance of gathering data and asking questions, and most importantly, learn the significance of these unique and vital mangrove ecosystems. Ultimately, it is critical that our next generation learn to be respectful of the planet, as well as learn about conserving and protecting wild places and animals. After all, it’s their planet too.