Sea-Level Rise Leading to Florida Mangrove "Death March," Study Warns

South Florida's mangroves are so vital to the area's unique ecosystem you can't even sneeze on the trees without upsetting environmentalists. Donald Trump infamously lost a negotiation to take over a golf course in Miami-Dade's Crandon Park partly because he wanted to remove 450 yards of mangroves. More recently, a Miami power couple was cited for illegal mangrove chopping and forced to replace the plants.

But a new study from Florida International University warns that, despite strict environmental regulations protecting the unique trees, carbon emissions from cars, power companies, and other fossil-fuel-burning industries have succeeded in all but killing South Florida's coastal mangrove population. The study, published recently in the peer-reviewed Journal of Coastal Research, shows that sea-level rise has pushed mangroves into a westward "death march" and that without coastal mangroves, Floridians should prepare for even worse storm surges and coastal flooding.

“You can see migration westward has stopped right where that levee is,” scientist Randall W. Parkinson said in a news release. (The Guardian first reported on the study earlier today.) “In many cases there is no space for them to migrate into — there’s development or some feature that blocks their migration."

Researchers at the FIU Sea Level Solutions Center used satellite imagery, soil and sediment data, and aerial photos from the 1930s to track what has become of the mangroves. In the '30s, red-mangrove-heavy wetland insulated much of the coastline from the ocean. But now, as seas are rising and drowning the plants, the trees have retreated to the L-31E levee on the eastern edge of Miami-Dade County, and the mangroves have nowhere farther west to go. Everything else past that line has been developed.

Check out this handy, albeit terrifying, slider from FIU showing the plants running away from the coastline:

FIU researchers warn that the coastline the plants occupy could become open seawater within the next 30 years. This is pretty bad news for humans, because mangroves work to buffer the coastline from storm surges, erosion, and saltwater intrusion.

The new data works to confirm previous studies about the Everglades and climate change, which pretty much uniformly caution that if carbon emissions aren't severely curtailed pronto, the Glades is in serious danger of vanishing. Last November, the International Union for Conservation of Nature (IUCN) labeled the Everglades the "most critical endangered" natural area in the nation thanks to a parade of threats, including altered water flow, invasive species overpopulation, and climate change.

And, in February, the Miami Herald warned that the ocean is rising so fast that the water-level changes are outpacing current efforts to restore the Glades. During the first half of the 20th Century, the Army Corps of Engineers dug canals through the state and drained the swamp so Northern settlers could live there. But that process diverted water away from its natural route, thereby killing huge swaths of the Everglades. Politicians and environmentalists drew up plans in 2000 to reroute the water back southward again, but an FIU study the Herald cited warned that those plans didn't properly take sea-level rise into account. (Many respected studies now say that two feet of global ocean rise is likely by the year 2100.)

Now FIU is again warning that rampant overdevelopment, combined with rising ocean levels, will drown Florida's globally unique ecosystem for good.

"They're done," researcher Parkinson said of the mangroves. "That's it."
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Jerry Iannelli is a former staff writer for Miami New Times from 2015 to March 2020. He graduated with honors from Temple University. He then earned a master's degree in journalism from Columbia University.