Can the regrowth of mangroves shield Miami from sea level rise? Mangrove-lined living shorelines can reduce floods, stabilize beaches, and cost landowners less money.

Mangrove forest
Mangrove forest located in the Mida Creek - Malindi Photo by Timothy K on Unsplash

Protecting Florida

This Florida island, which was more of a marshy sandspit than a piece of land at the turn of the century, was covered with mangroves. Mangroves were mostly recognized as the homes of alligators, other reptiles, and blizzards of mosquitoes due to their gnarled roots standing knee-deep in tidal waters. And by 1915, they had vanished. One of Miami Beach's founders, Carl Fisher, had stripped the island naked as his first move in transforming it into the legendary vacation destination it is today.

The future as seen by city leaders in the twenty-first century is different: they envision a resilient Miami Beach at the forefront of climate change, adjusting to rising seas and worsening storms by installing enormous pumps, elevating streets, and, yes, reintroducing the humble mangrove, which acts as nature's storm tide buffer. To establish a "living coastline" along the same length where mangroves were cleared out a century ago, volunteers will plant 680 mangrove trees in the largest park in the city next week.

Although mangroves were once thought to be doomed to extinction, their benefits to the environment today are practically unmatched. Even after Miami-Dade County recently rejected an Army Corps of Engineers proposal to build a substantial seawall, they are still difficult to sell here. According to the argument, the county did not present a substitute design because mangroves would obstruct the view.

Even though the trees are typically not very tall, they have dirty, gangly limbs. And let's not forget the mosquitoes.

According to Lisa Spadafina, assistant director of the Miami-Dade division of natural resources, "I don't believe people often think of mangrove shorelines as the desired approach to stabilize their homes."

However, it is generally known that mangrove forests may act as a shock absorber for hurricane-force winds and tidal surges. According to a 2020 study published in Scientific Reports, mangroves protect 15 million people worldwide from dangerous severe storms and prevent $65 billion in property damages. In 2004, one of the worst tsunamis in recorded history blasted over the Indian Ocean, demonstrating their importance. Mangroves protected Indian and Malaysian villages, reducing damage and fatalities. The Indian government outlawed the clearing of mangroves in 2005.

Mangroves, even in tiny stands, may protect coasts from erosion and purify contaminated water of poisons. The food, shade, shelter from predators, tidal surges, and heat that mangroves offer also serve as a nursery for birds, fish, crustaceans, and even sharks. In addition, mangroves store much more carbon emissions than terrestrial forests-up to five times more acres.

Mangrove Seedlings

Mangrove Habitat (IMAGE)
Mangroves, like these shown at low tide, provide important nursery habitat for juveniles of many marine species. © D. Malmquist/VIMS.

The arrival of the new mangrove seedlings at Miami Beach's Brittany Bay Park would seem to make them the main actors in the $1.8 million renovation of the waterfront park. To support efforts to combat flooding, the living shoreline there will combine natural elements (mangroves) with man-made features (a barrier) as South Florida confronts the possibility of a two-foot sea rise by the middle of the century.

Sea Level Rise

The resilience officer for Miami Beach, Amy Knowles, points off some of the city's raised streets and enormous pumps as she takes a recent morning stroll. "As sea levels rise, building up a living coastline is simpler than reconstructing a whole new bulwark." Is it the first line of defense? It's a piece of our complete toolkit of choices.

However, the city is constrained in what it can do. Its 55 miles of shoreline are wholly privately owned, except for five.

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