Go Mangrove!

April 16, 2016 -- In April 2013, this is what I said about mangroves during the "mission moment" at church:

When you live in this part of Florida, you know or you soon learn that native plants are important to our ecosystem. Mangrove trees are true natives, and they are our most valuable coastal resource. Biologically, they form the structure for a complex ecosystem that is the link between the land and the sea.

These mangroves stabilize our shorelines. Their root systems slow water flow, and that facilitates the deposit of organic material and sediment that provide nutrients that are the basis of the marine life food chain. Excess nutrients such as nitrogen and phosphorus are filtered from coastal waters by mangroves, and are incorporated into the leaves, branches and root systems of the trees.

Mangroves are important to fish. About 85 to 90 percent of all local commercial and recreational fish depend on mangroves for food and shelter. Other marine organisms attach to the mangrove roots and then filter water to trap and cycle nutrients. You could say that mangroves are the “nursery” of the sea. They are also valuable as rookeries and shelter for wading birds and brown pelicans.

These days, we often hear about the importance of forests for storing carbon. Worldwide, mangroves account for storage of more carbon than almost any other forest on earth. Florida has 469,000 acres of mangrove forest. Sanibel has about 11,000 of these acres of mangroves, and it has nine miles of mangrove shoreline.

Mangroves grow long skinny “fingers” or seeds called propagules. These fall from the tree and onto the ground or into the water. If they fall into the water, they float around until they get stuck in the sand and root and grow into a mangrove tree. If they land on the ground, the Sanibel-Captiva Conservation Foundation has a program that picks them up and takes them out into the water and plants them along the shoreline where they take root and grow into trees.


Now Tom and I live with a dense line of mangroves between our house and the water of Dinkins Bayou.  Oh, we had a couple mangroves in our backyard at our previous residence, but they were loners.  They weren't part of a line of defense they way our current mangroves are, on the edge of the tidal bayou.
Looking at the mangroves on the far side of the bayou, from our dock at sunrise.

The mangroves are so important to us that I've hired a professional tree firm to trim them properly.  We're waiting for our mangrove trimming permit from the City of Sanibel now.

That mangrove roots filter excess nitrogen and phosphorus from our coastal waters is a godsend.  The mangroves cannot begin to deal with all the polluted water dumped on our estuary by the managers of Lake Okeechobee, but I think they must be helping some, because the water isn't as badly affected back here in the bayou where thick lines of mangroves defend both shores.  Here I haven't seen the dark brown water that has so clearly gushed into Pine Island Sound and San Carlos Bay, nearby.

Mangroves also defend against erosion.  As my friend Phyllis says, "they hold the land."  Here on the bayou, mangroves are far more effective in defending against erosion than sea walls are.  A combination of stones called "rip rap" and mangroves rooted through the stones is the best defense of all, I'm told.
White pelican swimming near mangroves on Dinkins Bayou.

Our mangroves are short enough to allow a water view from the main level of our house, yet tall enough to lend privacy to the lower level -- including the swimming pool.  But a neighbor told me that mangroves can be maintained even at the low height of two or three feet!  That I did not know.  It is good news for owners of ground-level homes who want to preserve their view yet control erosion of their land.

So now I'm a little confused about why so many waterfront homeowners refuse to let mangroves grow on the waters' edge of their properties.  The mangrove-less homeowners are also missing out on a great wildlife show.

Besides the plethora of birds that like to hang out in the mangroves, there are amusing little mangrove crabs that race up and down the branches and roots.  In the water around the roots, small fish seek shelter from bigger fish.  Dolphins routinely rush after fish who flee to the shelter of the mangrove roots as fast as they can.  This excitement we see nearly every day.

Our home without the mangroves would be like a picture without a frame:  okay, but much better with than without.  The mangroves give context, beauty, and function.  Mangroves provide privacy, excitement, and defense.  Go mangrove!
Mangrove behind our old home on Old Banyan Way.


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