Fence Post Writers on the Road: Mangroves important to the ecology of the Caribbean
June 23, 2014
“The fastest man in the world, Usain Bolt, is from Jamaica,” began our guide, Lollie.
Pointing out a window of the tour bus towards a pink, one-story building, he joked, “We went to school there together. I was faster than him in those days, though. He kept trying to steal my lunch.”
Born and raised in the area, Lollie had plenty of information to share with his tour group of 40.
“The father of Reggae music, Bob Marley, is from this land. American musician Jimmy Buffet has a home here. So does the actor Steven Segal.”
He gestured toward a large, palm-tree landscaped neighborhood as we drove past.
“Do you notice that most of the buildings are made out of concrete instead of wood? There’s a reason for that. We have many hurricanes in Jamaica, and the concrete stands up to them best.”
But after he pulled into Montego Bay — a popular water park — to hand us up onto a catamaran (sailboat) for the second half of the tour, Lollie got serious.
“Whatever you do, while you are snorkeling here, never, ever bother the mangroves. Don’t even tear a section off to look at it closely. They’re protected, and you’ll get heavily fined.”
Once carelessly cut down to make room for the resorts and houses built close to the water, mangroves are once again flourishing in the Caribbean.
Basically a thick line of shrubs and trees which are adapted to saltwater, they grow along the shoreline and provide habitat for smaller varieties of egrets, seagulls and herons as well as fish, shrimp and crabs.
According to the Mangrove and Coastal Wetlands Protection regulations, they are “particularly important as marine nurseries, and sources for the harvesting of shellfish.”
The actual word “mangrove” refers to “ecological groupings that are not necessarily related to each other.”
There are about 80 different species, ranging in height from short bushes to 60-foot tall giants. They “retard water movement and trap suspended materials and the remains of organisms. The accumulation of this organic material contributes to raise the soil level.”
Highly important to the survival of the outlying coral reefs, mangroves act as filters against any silt that might float out towards them, providing food for damaging algae.
And when the tides come in, they offer protection to such reef fish such as snapper, tarpon, and snook (a hard-fighter that is popular with anglers), providing safe nurseries for their young.
Mangroves are able to deal with the extreme levels of salt in the water by excreting it through both the roots and the surface of the leaves. The high magnesium content in the roots causes a reverse osmosis, so to speak, helping to eliminate salt as well. Some even store salt in their bark, and in older leaves, shedding it back into the water.
They have a tangled system of roots which arch downward. Those dig deep into the muck, firmly anchoring the vegetation. In the process, intertwining helps hold the soil in tightly, protecting against erosion.
Those roots spread out, forming “pneumatophores,” which grow up out of beach sand and soil and take in oxygen. Oxygen is brought in through “lenticels,” or breathing pores, which close tightly during high tide.
As those roots latch together, they form a tight weave that resembles a mat.
Sand and soil are held in place as humans walk across them, or drag their boats up to safe shelter.
And this time of year — hurricane season — that’s especially important.
“Those roots hold the mangroves firmly, resulting in a protective barrier against high winds and tsunamis,” our guide concluded. “They buffer the coast and help protect people” — which is by far the most important reason why mangroves are so valued in the Caribbean. ❖