It’s no secret that we at Lake Worth Waterkeeper are big mangrove fans.
At least twice a month you can find us and our intrepid volunteers tromping around in our mangrove planters at Jewell Cove and Bryant Park, picking up trash, looking for fiddler crabs, and checking on our mangrove nursery. We love mangroves so much because we understand and appreciate what they do for our human and non-human communities, our mental and physical well-being, and even our economy!
In much of south Florida, our economy is tourism based– fishing, diving, boating, and almost perpetually sunny beaches are huge draws to people from all over the world. Businesses of all kinds reap the economic benefits of tourists and snowbirds flocking to our coastal communities – and we have mangrove systems to thank for most of it!
Mangroves are considered a nursery ecosystem, providing food and shelter for hundreds of species of juvenile fish. An estimated 75% of the game fish and 90% of the commercial species in south Florida rely on mangrove systems during at least part of their life cycle.
Florida Fish and Wildlife Conservation Commission (FWC) estimates that saltwater commercial fishing generates $3.2 billion in income, and supports 76,700 jobs. Saltwater recreational fishing brings in around $9.2 billion, and supports 88,501 jobs. Many species of tropical fish also rely on mangroves during their life cycles. In a study published by the National Oceanic and Atmospheric Administration (NOAA) in 2021 looking a reef-related diving and snorkeling, it was estimated that Palm Beach County accounted for the highest economic impact and number of jobs supported by the dive industry. Results from this study show that reef- related diving and snorkeling in Southeast Florida support 8,668 jobs and generate about $902 million in total economic output over the course of a year. We owe a LOT of our tourism dollars and jobs to these mangrove ecosystems!
Mangroves play such a large role in supporting fish, and other marine and estuarine (and even some freshwater) species because they create habitat. Specifically, the red mangrove, or walking tree, with its distinctive aerial root system, plays a unique and essential role in creating productive estuarine habitat. Their roots grow down into the water and create underwater labyrinths perfect for hiding from larger predators. The submerged roots also provide hard substrate for organisms like oysters, barnacles, sponges and other invertebrates. Their leaves drop down into the water and decompose into nutrient rich detritus, feeding a variety of organisms and creating a strong base for many food webs, including those that support those valuable game and commercial fish species!
Mangroves are also allies in the fight against climate change. They are among the most carbon-rich forests in the tropics, sequestering up to four times as much carbon as rainforest per unit area. One estimate puts the carbon sequestration services of Caribbean mangroves at ~$6.6 billion. Continued loss of mangroves would release this dangerous stored carbon into the atmosphere.
The tangled, dense roots and branches of the red mangrove also act as barriers against storm surges and wave action that can cause erosion, property damage, and even loss of life. A scientific study published by the Nature Conservancy, UC Santa Cruz, and RMS found that the presence of mangroves significantly reduced the damages from storms and are a strong first line of defense for coastal communities.
The study concluded that mangroves in Florida prevented $1.5 billion in flood damages and protected over half a million people during Hurricane Irma in 2017, reducing damages by nearly 25% in counties with mangroves. According to the study, mangroves most effectively reduce flood risk where they are abundant and located in front of areas with high densities of people and property. In vulnerable Miami-Dade County, urban coastal mangroves protected high-value coastal properties from over $134 million in potential flood damages from Hurricane Irma. According to an International Union for Conservation of Nature (IUCN) summary, the insurance industry is increasingly interested in the role mangroves can play in protecting property, even leading some to lower premiums in areas where mangroves are shown to reduce property damage from storms and therefore, large insurance pay-outs.
In comparison, the Snook Island restoration project off the Lake Worth Golf Course cost about $18 million, and when Hurricanes Frances and Jeanne hit mid-construction, neither the project, nor the Lake Worth Golf Course shoreline sustained damage.
In areas where those systems have already been lost or degraded, there is a strong economic and ecological case for mangrove restoration. Approximately 70% of the Lake Worth Lagoon shoreline is man-made bulkhead. We have a wonderful opportunity in our communities to invest in living shoreline preservation and restoration. In many cases, protecting and restoring whole mangrove systems has been shown to be less costly than building and maintaining artificial storm protection, and they provide many more ecosystem services, such as habitat creation, than artificial shorelines.
It is clear from the research that natural, intact mangrove systems offer the most value for local communities, governments, and investors.
It is difficult to quantify in dollars the total value of natural places. These estimates still don’t adequately capture the entire value of our mangrove systems, and in reality, they are likely even more valuable than the numbers reflect. While we can put a price on certain parts or functions of an ecosystem, how much is a day spent fishing with your children, or a once in a lifetime encounter with a sawfish truly worth?
These are questions that only we as individuals and communities can answer. The research does make one thing clear: the high value of these intact, healthy ecosystems challenges the generally held assumption that profiting off of nature has to involve extraction. In many cases, and certainly when it comes to mangroves, nature is more valuable to us when it is protected, restored, and allowed to thrive.