by Kristen Hoss
The mangrove tree, a brackish water inhabitant, once lining Florida’s bays and intercoastal waterways, is the mightiest tree in the world, yet it has fallen in the forest and no one seems to have heard it. In Florida, there are three vitally important species of native mangrove—red, black and white—names based on the hue of their bark. Yet, in this day and age, when talks of climate change, resiliency, sustainability and sea level rise abound, the role and importance of the mangrove seems to have been ignored by many.
The mangrove tree provides so much to sustain our way of life; whether a person lives in New York, Alaska or Key West, mangroves are a silent and mighty hero to us all. Let’s talk basics. Mangrove leaves, which become detritus, are the base of the marine food chain, supporting an estimated 90 percent of the commercial fisheries in Florida and many similar locations sharing the 25-degree south to 25-degree north latitudes, not to mention approximately 70 percent of sport fish offspring utilize mangrove swamps as a nursery.
Florida is the fishing capital of the world, producing 7.5 billion dollars (Myfwc.com-2006) U.S. Dept. of Interior study) in revenue each year, meaning mangroves are important to the local and global economy. Mangroves and their adjacent and interdependent habitats such as sea grass beds and coral reefs (aka coastal systems) bring in dollars in the form of ecotourism and ecosystem services, providing a global economic value between $25 and $29.8 billion annually (CoralReef.noaa.gov), 1.6 billion in ecosystem services by mangroves in the U.S. alone (iucn.org).
Being that South Florida has about 469,000 acres of mangroves (dep.State.fl.us) and supports the world’s third largest coral reef, residents gain from a significant portion of that money. The money gained is partially through ecotourism, thanks to the 1300 species of mangrove-loving wildlife, including 220 fish, 24 reptile and amphibian, 18 mammal and 181 bird species (Soils.ifas.ufl.edu/wetland) providing habitat for 67 animals per square meter at times (jstor.org/stable/1932034), not including the small things people generally do not think about—like bacteria—a very important base food source/ nutrient cycler that digests and converts carbon into a food source for organisms higher on the food chain, a food chain that humans are the top of and dependent on. Yet the mangrove forests have been destroyed by Floridians since our initial settlement in the 1800s. In the 1940s, areas up to 87 percent have been lost (dep.State.fl).
So, let’s say that hand sanitizer is everyone’s friend (i.e. death to all bacteria) and seafood is not a priority in some circles. How about property and flood insurance? The mangroves, about 70 species worldwide, hold onto soil. Not only do they stabilize shorelines and valuable property, but the red mangrove is called the “walking tree” because its prop roots not only hold soil, but they build land. In some areas of the world such as Bangladesh, a country with a fragile shoreline existence like South Florida’s, planted mangroves on uninhabitable sediment gained over 300,000 acres of land as the mangroves marched seaward, thus decreasing flood potential to coastal developments and increasing usable space. In a state that is increasingly flooded with beaches and coastlines eroding, sometimes smothering reefs, it seems like mangroves left alone or replanted as living shorelines may provide a natural solution to an unnatural problem caused by coastal development and seawalls. Studies have shown (Nature.org) that areas built with plenty of open space and natural protection, such as mangroves, around them are significantly less prone to flooding, thus decreasing loss, insurance costs and risk—a significant savings to the Florida homeowner.
Being that more than 75 percent of people in Florida live in a coastal county, mangroves deserve some notice. The 25 percent of the population inland benefit too. Mangroves not only buffer hurricanes, but they also clean two things that connect us all globally—water and air. They filter pollutants from runoff and are a natural belt of air-filtration, hugging the midsection of the earth. They breathe in and hold onto approximately 15 times more carbon (CO2), a common by-product of the burning of fossil fuels, than any other forest on the planet, even more than rain forests. The carbon is stored in their trunks and in the soil they maintain. Globally, 30 to 50 percent of mangroves have been deforested in the last 50 years, and continue to be deforested at a rate of 370,000 acres per year for aquaculture, a view, development and in Miami, a boat show. When a mangrove forest is destroyed, all of that CO2 is released, accounting for 10 percent of the annual increase.
Is the long-term, economic and intrinsic loss worth the temporary monetary gain? Many people say “no”, and work to restore mangrove habitat. When mangroves are restored, it costs approximately $10 million per acre to restore a mangrove forest to 15-year maturity. At Port Everglades, the initial cost of restoring the 8.7 acres of mangroves that were removed, is $15.7 million (Broward.org). It is less costly and easier to conserve what we have remaining than to restore it later.
You can maintain the mightiness of the mangrove! Join a mangrove restoration such as the one Youth Environmental Alliance is doing in November (calendar at YEAFrog.org); join the Florida Master Naturalist course (MasterNaturalist.org). When staying at resorts or investing in development, avoid those that destroy mangrove habitat; if your residence borders brackish water, plant mangroves along the shore (note: once they are planted, they are protected); when buying seafood, avoid farm-raised from farms built in mangrove habitat (mostly imported) and move to “Best Choice” wild-caught Oregon pink shrimp or “Good Choice” Gulf shrimp; and work with your local commissioners and town managers to ensure that your community is an active participant (this includes planting or maintaining mangrove-forested areas) of the Community Rating System (CRS) which is a part of the National Flood Insurance Program (NFIP) to decrease community-wide insurance premiums.
Kristen Hoss, executive director of Youth Environmental Alliance and FLERA, is an educator and ecological consultant who leads the Florida Master Naturalist program in Broward County, produces in-school environmental and science education programs, and provides expertise for ecological surveys and monitoring. She has a BS in Ecology and Evolutionary Biology, a Masters in Conservation Ecology and Wildlife Sciences, and more than 28 years in the field of ecology (marine, aquatic and terrestrial) and the management of natural areas and wildlife. Her work has been featured on the National Geographic Channel and in multiple publications. Email her at Kristen@YEAFrog.org.