Nature of the Ten Thousand Islands

Jan 8

4 min read

Here in the mangrove community elevation makes a difference in the construct of the forest.

Holding on! A few trees survived the impacts of storms. Sand is pushed up from the eroded shore.

On our way toward our Keys destination we spent a few days rambling down the Ten Thousand Islands with our friends Michael and Linda aboard sistership Zydeco. While at anchor, we took a few dinghy jaunts through the labyrinth of mangrove islands, exploring coves and small inlets and landing on sandy beaches.

Passing through the area it's a treat to see some wonderful bird life, including hundreds of white pelicans, shorebirds, wading birds and some waterfowl. It was unexpected to be seeing lots of little blue herons - both juveniles and adults. It was the most common species of wading bird we were seeing around our anchorages. And, it's always a treat to come close to ospreys starting to refresh their nests on the channel markers.

Yellow-crowned night-heron - photo by Linda R.

The plant community of the islands are comprised of three mangrove species and buttonwood. Where they occur is stratified by the elevation of the land. A few inches or a couple feet of elevation make a big difference in the composition of the islands' vegetation. You will find red mangroves in shallow tidal areas. When established and mature, their prop roots form a dense tangle of arching interlaced structure. Black mangroves and white mangroves occupy a little higher ground to survive. Buttonwood (not a true mangrove species) occupies the highest elevations.

The red mangrove community on the remote islands in the Ten Thousand Islands National Wildlife Refuge and the back country of Everglades National Park are mature forests. Although, in the past, some buttonwood was harvested to make charcoal, the wet-footed woodlands have avoided commercial exploitation. Except for the places where the effects of storms have been destructive, the islands are densely forested. Thick canopies shade out the understory. A peek inside shows an impenetrable weaving of arching prop roots that knits together the forested wetland.

It is interesting to see the changes storms have wrought upon the windward shores of the mangrove islands.

Eroded beaches and toppled trees evidence the power of storms to change the coastal landscape. The condition of the mangrove community is a history of past hurricanes.

Maybe these dead snags, weathered white by the sun, date back to Hurricane Irma 2017.

The straight trunks are characteristic of trees that grew up through openings in the mature canopy toward the sunlight. It's an excellent example of phototropism. Their growth followed the light rather than the usual twisted morphology that is more characteristic of mangroves. The scientific name, Rhizophora mangle, is appropriate, translating to "mangled roots."

Storms take out trees creating bare ground and openings in the forest. Pioneer plants are the first to get established in a process called plant succession. In the mangorves, it's more like re-growth since the composition of the habitat doesn't change much.

Sprouting propagules colonize an open spot created when a tree was toppled. We are guessing these are probably from Hurricane Ian in 2022.

These shrub-sized red mangroves grew up in an opening, maybe created several years ago by a downburst. Note the spindly tall survivors in the background - bent but not broken.

Damage to the mangroves is sporadic. Some areas are knocked way back while leeward exposures look healthy and untouched. Nature is remarkable in its regeneration and resilience. In a few places we saw isolated black mangroves and buttonwood towering 20 or 30 feet above the canopy. These stalwarts of the swamp somehow survived the onslaught of winds and waves while other trees that were part of the same groves succumbed to the storms.

Curious that these tall black mangroves withstood the storm, but others of the same height didn't.

What is not likely to recover soon, what with sea level rise and climate change, is the shorelines that have eroded. Mature forests are upended and the profile of the littoral zone is changed such that the tidal areas are probably too deep to allow recolonization of the red mangroves. It would be interesting to look at aerial photographs to see the changes to the shapes of the mangrove islands over time.

A sandy spit emerged from a former vegetated area. In time, it will regrow a mangrove forest or maybe retreat to a shallow shoal. — Perhaps the surge from Hurricane Milton in 2024 created this sandy spit accreted at the end of Tiger Key. Only time will tell if the sand washes back into the bay to become a shoal, or becomes a revegetated island. For now, it's a great place for shorebird nesting and loafing.

It is a privilege for us to transit this wild coastline, taking the road less travelled. — It is a privilege for us to transit this wild coastline, *taking the road less travelled.*

White pelicans flying by Bay Breeze - photo by Linda R.

While the landscape is not dramatic with geologic spectacles, or majestic forests, we have a deep affection for the pure wildness of the Ten Thousand Islands National Wildlife Refuge and Everglades National Park. It stirs our imagination. Perhaps that is born of our introduction to these places during our South Florida childhoods of 1950s and 60s, but it could be that the delight of sailing, solitude, wildlife, and sunsets heartens our souls.

Zydeco and Bay Breeze (R) off Camp LuLu Key

How thankful we are to enjoy these places again with a hope that nature will adapt and prevail even in the face of the unprecedented pace of climate change.

Thanks for reading!

Marvin and Lee

01.08.2025