Critters in Our Midst - Mangrove Forests

Happy Fall! It’s finally arrived... if only on the calendar. There’s been a small drop
in temperature (the 80’s instead of 90’s) and the mosquito count is noticeably
down. I don't want to jinx us, but we're two months shy of the end of 2024
Hurricane Season and we haven't had a powerful hurricane... yet. Hurricane
destruction comes in waves; first from the wind and water, which results in power
outages, broken infrastructure, roofs opened and while mosquitos are eating you
alive, the second wave of destruction which I fear most begins, when the
unemployed surfers with chainsaws appear and start cutting down our mangrove
shoreline to improve a view.

Distinctive snorkel roots from the Black Mangrove stick out from the ground like fingers, and grow alongside Red Mangrove prop roots.

The strongest hurricane winds do not uproot the mangroves, but can shake the
trees so violently that the bark peels off, exposing the cambium layers to salt spray
and waves, quickly killing the tree. Both dead and living mangroves are protected
as outlined in the 1996 Mangrove Trimming and Preservation Act. There are very
specific regulations and heavy fines for illegal mangrove trimming. Florida law
allows property owners and/or professional trimmers to trim mangroves to improve
their view or access navigable waterways. Visit https://floridadep.gov and search
for Mangrove Trimming and Preservation Act to learn more. Always check with
local environmental officials before trimming mangroves.

A white ibis observes from a mangrove branch.

A roseate spoonbill probes for mollusks and other invertebrates in the sediment.

The Keys have four tree species in their mangrove forests: the Red Mangrove
(Rhizophora mangle) with it’s spider-like prop roots and cigar shaped seeds, the
smaller White Mangrove (Laguncularia racemosa) with it’s pea like seeds, the dark
barked Black Mangrove (Avicennia germinans) whose distinctive aerial roots stick
up from the ground like thin fingers, and Green Buttonwood (Conocarpus erectus),
the tree with the distinctive bark which looks as if it want to come off.

Red mangrove seeds develop on the tree and when they fall into the water they soon sprout roots along rocky coastlines.

White mangrove seeds are pea-like.

All mangroves disperse their seeds by water. The red mangroves are particularly
important because their high arching prop root systems entrap sediment and
decayed organic materials, making them not only an essential habitat in the
marine food chain, but also “land-builders” which have formed over 200 islands in
Florida Bay. Mangroves are cold sensitive plants, that range from the St. Johns
River on the East Coast, down through the Florida Keys, and up Florida’s west
Coast to Cedar Key. North Key Largo is home to about 8,000 acres of
mangroves.

Mangroves are the nursery for the oceans. When they are destroyed it upsets the
ecosystem. Fishermen know that 75% of the game fish and 90% of the
commercial species use mangrove roots and shallow waters to shelter from
predators until they reach a size large enough to fend for themselves. Mullet,
mangrove snapper, snook, tarpon, shrimp, sea trout and blue crab call the
mangroves home. The American crocodile lives in the mangroves and the
mangrove water snake hides out among the tangle of prop roots and branches.
Bottlenose dolphin feed on fishes associated with mangrove systems.

Manatees are frequently observed swimming in proximity to mangroves.

Manatees (Trichechus manatus) feed on seagrasses and other submerged
aquatic plants and are frequently observed swimming in proximity to mangroves.
On a visit to my favorite mangrove lined canal, I sensed a photograph, however
the water needed cleaning of a landscaper’s errant grass clippings that littered the
surface. As I skimmed the water with a net to catch the clippings, my splashing
attracted a West Indian manatee. Next a small nurse shark swam by... the place
was alive. I thought all I needed to complete the scene was a bird. As I positioned
the camera to capture the photo, a green heron flew in and perched on one of the
prop roots. At that moment I felt as if I were Dr. DoLittle on an animal adventure.

The rare and endangered Mangrove Diamondback (Malaclemys terrapin) only
lives in the brackish back waters of the Florida Keys and Everglades. White
Ibis (Eudocimus albus) feed on crabs and Roseate Spoonbill (Ajaia ajaja) prey on
mollusks and other invertebrates living within the sediment. The entire Everglades
population of the wood stork (Mycteria americana) nests only in mangroves.

The reclusive Mangrove Diamondback terrapin lives in the brackish waters of the Florida Keys and Everglades. Photo by: Morgan Barnes

Pelican guano coats a small mangrove island.

The Red Mangrove, the “walking tree” found growing on the shorelines, is the
basis for an impressive natural ocean filter system for litter dumped at sea,
highlighting the importance of individual and organized coastal clean-up efforts.
Back in the early 80s, my husband Ted and I would explore the mangrove
shoreline, and leave with treasures like old buoys and wormy driftwood. It was
athletic work as we balanced on the giant prop roots and labored to free a piece of
debris from the mangroves. We called the shoreline our “Overseas Lumber
Company.” Once home Ted would rip the driftwood into strips and make the most
beautiful wormy frames for displaying my photographs.

As I sit musing about some of the best times of my life, Ted appears steadied by
his walker. I great him cheerily “Happy Fall!” He replies, “Trying not to.”

All we need to do is understand some words and the context helps us out with the
rest.

Red mangrove shoreline at dusk. Seagrape trees often grown near red mangroves.

A little green heron sits undercover of the mangroves.