Guardians of the Shore: The Mangroves of Fort Matanzas National Monument

Mangroves are a vital component of coastal ecosystems, offering numerous ecological benefits. Fort Matanzas, situated on a barrier island known as Rattlesnake Island, is surrounded by a diverse landscape of sand dunes, mangroves, and various types of shrubs and trees. While the fort has historically provided safety for humans by protecting the land, the mangroves have played a crucial role in shielding the area from storm erosion and floods. Adjacent to Rattlesnake Island lies Anastasia Island, home to the ranger office and visitor center. Both islands boast thriving populations of Red, Black, and White mangroves. To better appreciate the diversity and beauty of these essential coastal defenders, I set out to explore the coastline and managed to snag a few pictures seen below. 

Black Mangrove
Red Mangrove
White Mangrove

Black Mangroves

While walking down the salt marsh trail, the first mangrove I came across was the black mangrove (Avicennia germinans). They stand out during the summertime with their small white flowers and elongated, leathery leaves with a silver underside. Their bark is dark and scaly. One unique feature of black mangroves is their specialized root system, known as pneumatophores, which are pencil-like projections that protrude from the soil. These roots allow the plant to obtain oxygen in waterlogged, anaerobic conditions. Since this area is an intertidal zone located right off an estuary, many of these mangroves can be found. In the picture to the right, you can spot the crystallized salt that has been excreted onto the surface of the leaves.

Black Mangrove leaves with crystallized salt
White Mangrove leaves

White MANGROVES

A similar but distant family member to the black mangroves is the white mangrove (Laguncularia racemosa). They can be easily differentiated from the red and black mangroves by their leaves. As you can see in the picture on the left, white mangroves have oval-shaped leaves that are light green with a pair of distinctive glands at the base of each leaf blade. These mangroves tend to occupy the furthest point from the water in high-tide areas. Like the black mangroves, white mangroves have the ability to excrete excess salt, which can also be seen on the surface of their leaves. Additionally, their fallen leaves contribute to the detritus that fuels the coastal food web, supporting numerous species living around them. This particular white mangrove was sitting right next to the black mangrove from the picture above.

red mangroves

Last but not least, is the Red Mangrove (Rhizophora mangle)! This one was a bit harder to find as there were only a few of these trees around the salt marsh trail. The mangrove that I was able to get a picture of, lived right along the shoreline, these are typically found closest to the water, often in tidal areas. They are easily identified by their distinctive prop roots, which extend from the trunk and branches, providing stability in soft, muddy soils. Unlike black and white mangroves, red mangroves do not have pneumatophores; instead, they rely on these prop roots for oxygen exchange. As shown in the picture on the right, these prop roots jut out of the soil, with oysters clinging to them. The leaves of Red Mangroves are dark green, glossy, and broader compared to the lighter, oval-shaped leaves of the white mangroves.

White Mangrove tree with oysters

preservation

While each mangrove has distinct differences they all do a really good job in taking care of our coastlines. Each of their unique root structures not only aids in supporting the plant itself but it also contributes to the ecosystem’s overall health. They do so by creating amazing habitats for so many creatures including mollusks, jellyfish, and other invertebrates. Even their leaves contributes to their environment, when the leaves drop to the sandy floor, they become detritus which feeds the wildlife. To the right is a video of what seems to be an Atlantic Sand Fiddler crab “meeting”.

 

In addition to providing a sanctuary for these critters, they also act as a natural barrier against storm surges and erosion. However, due to climate change and human disturbance much of these mangroves species are declining in numbers. Fort Matanzas takes great care of their trees reducing disturbance and conserving the ones they have in the park. To ensure the survival of these trees and the preservation of the island itself, we must continue prioritizing the conservation of dunes and mangroves, as they are vital in dissuading erosion. 

No Comments

Sorry, the comment form is closed at this time.