The Benefits of Mangroves

Living on a barrier island like Marco, we are constantly reminded of the incredible benefits of mangroves to Florida’s coastal environment. If you are a new transplant to Marco Island, you will learn early on through the lectures offered at Rookery Bay National Estuarine Research Reserve and also from the Conservancy of Southwest Florida that mangroves play a critical role in our marine ecosystem.  We learned that mangroves filter the water, act as a nursery habitat promoting healthy biodiversity, and also protect our coasts from storm surges and the impact of major storms and hurricanes.  

According to the Florida Department of Environmental Protection (FDEP) website,mangroves thrive in salty environments because they can obtain freshwater from saltwater. Some secrete excess salt through their leaves, while others block the absorption of salt at their roots. FDEP website also states, “Many animals find shelter either in the roots or branches of mangroves. Mangrove branches are rookeries, or nesting areas, for beautiful coastal birds such as brown pelicans and roseate spoonbills.” Additionally, “Mangroves can help prevent erosion by stabilizing shorelines with their specialized root systems. Mangroves also filter water and maintain water quality and clarity,”added.” 

Walking north from Residents Beach to the Big Marco Pass/Sand Dollar Island berm area, around the location of the Southern breach, if you look to your right across the narrow lagoon, you will notice a narrow strip or fringe of mangroves.  

The red mangrove (Rhizophora mangle)is easily identified by its tangled, reddish roots called prop roots, which add to its name as “walking tree.” It appears to be standing or walking on the surface of the water closest to the water’s edge.  

The black mangrove (Avicenniagerminans)can be identified with its numerous finger-like projections called pneumatophores, which protrude from the soil around the tree’s trunk. 

At low tide on September 20th and 21st at Big Marco Pass/Sand Dollar Island, sections of red and black mangroves looked brown, with their roots buried deep in sand. Buried roots are more noticeable during low tide events. “Mangroves are dependent on tidal ebb and flow to survive,” says the FDEP website.As storms overwash barrier islands, mangroves that were once in the water can be buried by sand, losing their connection to the tidal heartbeat. 

According to the FWC website, “Despite these benefits, human activities such as coastal development are responsible for destroying more mangrove forestsworldwide than any other type of coastal habitat. While large extents of mangrove forest in Florida have been lost to coastal development, mangroves are now protected by law in Florida to prevent future losses of these important coastal habitats ”