Their arching prop roots look like so many spindly legs, an army of alien invaders paused for a quiet soak in the shallows. The mangrove is one of only a handful of tree species on Earth that can withstand having its roots sitting in saltwater, immersed daily by rising tides, and that thrives in little soil and high levels of sulfides. The mangrove's hardiness is just one of its oddities.
Long hair, long beard, Thomas J. Smith has been jokingly called Jesus de los Manglares, Jesus of the Mangroves. An ecologist and environmental scientist with the U.S. Geological Survey in St. Petersburg, he studies coastal ecosystems "and the importance of mangroves in the detrital food web." "Detrital" as in "detritus," as in accumulated organic gunk, the accretion of which Florida's seething, slithering biomass attends to with a heedless vigor.
Mangroves are natural land builders, says Smith. Tubules about the heft and length of an excellent Cuban cigar sprout on the parent tree (they're not seeds: like mammals, mangroves are "viviparous," bringing forth live young), drop off and bob in the brackish water until they snag in the shallows. There, the tubule begins to grow to a tree, its leaves dropping and getting trapped along with seaweed and other plant debris. This organic slurry is the bottom of the food chain, supplying food, breeding area and sanctuary to tiny marine creatures.
Enough tubules shore up and a little island or "key" begins to take shape, the buildup of sediment and debris creating a thick layer of organic peat upon which other plant species begin to grow. Soon the tangle of trees and roots is extravagant enough to support bird life and other animals.
"Sometimes you're walking the boardwalk early in the morning at Weedon Island Preserve, and you see a roseate spoonbill feeding in the flats," Smith says. "There are things in nature that are important even if the human eye can't see them — all sorts of hidden beauty in them there mangrove forests."
The world's mangrove forests are disappearing faster than coral reefs and rainforest. Beyond threats from fish farms and urban and industrial land-use change, climate change looms as potentially ruinous.
"Mangroves have this ability to build peat," Smith says. "There are places in Everglades National Park where sediment is six or seven meters deep. If sea levels are rising too fast, they won't built peat fast enough to keep up."
Sea level threats aside, mangroves in Florida are better protected than those in many places. You can trim them, but do not spindle, mutilate or taunt a mangrove or face steep penalties.
Slipping into his Jesus de los Manglares persona, Smith intones, "Verily, verily I say to thee, don't cut down that mangrove tree."