Times of the Islands Winter 2019/20

green pages newsletter of the department of environment & coastal resources
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.
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.
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,
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