Wednesday, September 30, 2020

Mangroves…Florida’s “Walking Trees”

Photos by Bob McConvilleMangrove trees in the background, a great egret prepares to land in search of a meal.

Photos by Bob McConvilleMangrove trees in the background, a great egret prepares to land in search of a meal.

Stepping Stones
Bob McConville
Master Naturalist 

Take a boat ride through Rookery Bay and you will see them. Head the other direction towards Florida Bay and, undoubtedly, they are prominent. Just walk to Tigertail Lagoon here on Marco and they can’t be missed. Mangrove trees are everywhere!

Worldwide there are more than 50 species of mangrove trees. Here in Florida three species call our state home. They are the red mangrove, black mangrove and the white one. Of these three the red is probably most well known.

They are some of Florida’s true natives, thriving in salty environments. All need fresh water to survive in their habitats, so they find ways to adapt. Some secrete excess salt through the leaves while others block the salt at their roots.

More than 450,000 acres of mangrove forests contribute to the overall health of Florida’s southern coastal zone. This ecosystem is able to collect and cycle various organic materials, nutrients and chemical elements. The roots can provide attachment surfaces for marine organisms, and they too will filter water through their bodies to cycle additional nutrients that are vital to even more marine life.

This relationship between the mangroves and the life that it harbors cannot be stressed enough. They provide protected nurseries for fish, crustaceans and shellfish and they also provide food for these species as well.

In addition to the marine life, many animals find shelter in the branches and roots of these mangroves. These trees are rookeries, or nesting areas, for many of our coastal birds.

Of the three species in our state, the white mangrove will usually occupy the highest elevation. It does not have the visible aerial root system that is seen in the black and red mangroves. The white is most easily identified by its leaves. They are elliptical and have a yellow-green color and have two very distinguished glands at the base of the leaf blade where the stem starts.

The black mangrove usually is found at a lower elevation than the white. It is identified by the finger-like projections that protrude from the soil around the tree’s trunk. Many black mangroves can

This 2-year-old bottle nosed dolphin plays near the mangrove trees along the intracoastal waterway.

This 2-year-old bottle nosed dolphin plays near the mangrove trees along the intracoastal waterway.

be found at Tigertail Lagoon, in the calmer saltwater basin.

The best-known and most common mangrove tree in South Florida is the red one. This tree is easily identified by its tangled, reddish roots, called “prop roots.” Because the tree seems to be walking on water, or standing on the surface when the roots are exposed, it has been dubbed the “Walking Tree.”

In actuality, these prop roots suspend the tree over the water, giving it extra strength and protection. The ability to exclude salt occurs through a filtration process at the roots. Membranes prevent most salt from entering the tree, while allowing water to pass through. This ability to exclude salt content allows this tree to grow where others cannot, limiting competition from other plant and tree life.

All three of the species mentioned utilize a remarkable method of reproduction. Seeds sprout on the trees and drop to the soft soils around the base to grow. Some of these seedlings, like the red mangrove, are transported by currents and tides to other suitable locations.

Suitable as a nursery for many marine creatures, the mangrove habitat is also home for raccoons, possum, deer, bobcat and several other land animals, as well as many bird species.

Since Florida’s mangroves are a tropical species they are sensitive to extreme temperature fluctuations, as well as subfreezing conditions. The salinity (salt content) of the water, the tidal rise and fall, the water temperature and soil base may also affect their growth and distribution.

Mangrove trees are important in many, many ways. They provide nurseries and nesting areas. They are home to bird species and to some of our land animals. Their continued existence in South Florida is very necessary. State and local laws have been enacted to protect Florida’s mangrove forests.

Local laws may vary from one area to another.

Let’s hope that future generations will enjoy this habitat as we do today!

Bob is the owner of Stepping Stone Ecotours and a naturalist for the dolphin survey team on board the Dolphin Explorer. He is a member of Florida SEE (Society for Ethical Ecotourism). Bob loves his wife very much!!!!

One response to “Mangroves…Florida’s “Walking Trees””

  1. George Dyal says:

    Great article.

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