As the only tree species that can tolerate salt water, mangroves are one of the world’s most unique plants. They provide valuable nursery habitat for fish, serve as a mecca for birdwatching, and protect people and property along our coasts from the impacts of erosion and storms.
Although mangroves are a common feature along the coasts in much of the Florida peninsula and south Texas, warming temperatures have caused them to expand their range northward in recent decades. Mangroves are now found in parts of Louisiana and Mississippi and along the Atlantic coast. This expansion across the upper Gulf could affect the ecological, economic and cultural character of more than half of the contiguous U.S. coastal zone.
Unfortunately, many challenges threaten the health of mangroves. Human impacts such as dredging, filling, water pollution, alteration of freshwater flows and development can lead to mangrove erosion and habitat destruction. When mangrove forests are cleared and destroyed, they release massive amounts of carbon dioxide into the atmosphere, contributing to climate change. Climate change brings sea-level rise, more frequent and more hurricanes and other severe weather events like winter storms that hit Louisiana in January 2025 and Texas in February 2021.
With such coastal challenges created by growing populations, burgeoning development and climate change, risks to people and property from flooding and storm surge are on the rise. Mangroves provide valuable flood protection and risk-reduction benefits to these coastal areas, and yet they face an uncertain future.
Benefits of Mangroves
Mangroves provide numerous benefits to both people and wildlife. They help stabilize coastal ecosystems and prevent erosion. Mangroves also provide natural infrastructure and protection to populated coastal areas by reducing flood impacts during extreme weather events such as hurricanes. Mangroves along the Gulf Coast of Florida prevented millions and in some cases billions of dollars of damage to coastal homes located landward of the mangroves in hurricanes Irma and Ian.
Mangroves are important to natural ecosystems as well. Their dense roots help bind and build soils. Their unique above-ground roots slow down water flows and encourage sediment deposits that reduce coastal erosion and mitigate impacts from sea-level rise. The mangrove's complex root systems filter nitrates, phosphates and other pollutants from the water, improving the water quality flowing from rivers and streams into the estuarine and ocean environment.
In addition, mangroves provide an especially beneficial ecosystem service as we face climate change. Mangrove forests capture carbon dioxide emissions and other greenhouse gases from the atmosphere, trapping and storing them in their carbon-rich flooded soils for millennia. This buried carbon is known as “blue carbon" because it is stored underwater in coastal ecosystems like mangrove forests, seagrass beds and salt marshes.
A wide array of wildlife including birds, fish, invertebrates, mammals and plants find valuable habitat and refuge in mangrove forests. Estuarine habitats with coastal mangrove shorelines and tree roots are important spawning and nursery territory for juvenile marine species including shrimp, crabs and many sport and commercial fish species, such as redfish, snook and tarpons.
Mangroves also provide nesting areas for coastal wading birds such as egrets, herons, cormorants and roseate spoonbills. In some areas, red mangrove roots are ideal for oysters, which can attach to the portion of the roots that hang into the water. Endangered species, such as the smalltooth sawfish, manatee and hawksbill sea turtle, utilize coastal ecosystems that include mangroves as an integral part of their important habitat.
People also benefit from the natural experiences that mangroves offer. Whether birding, fishing, snorkeling, kayaking or paddle boarding, people can enjoy the therapeutic calm and relaxation that comes from exploring these unique coastal ecosystems.
A wide array of wildlife including birds, fish, invertebrates, mammals and plants find valuable habitat and refuge in mangrove forests. Estuarine habitats with coastal mangrove shorelines and tree roots are important spawning and nursery territory for juvenile marine species including shrimp, crabs and many sport and commercial fish species such as redfish, snook and tarpons.
Mangroves also provide nesting areas for coastal wading birds such as egrets, herons, cormorants and roseate spoonbills. In some areas, red mangrove roots are ideal for oysters, which can attach to the portion of the roots that hang into the water. Endangered species such as the smalltooth sawfish, manatee and hawksbill sea turtle utilize coastal ecosystems that include mangroves as an integral part of their important habitat.
People also benefit from the natural experiences that mangroves offer. Whether birding, fishing, snorkeling, kayaking or paddle boarding, people can enjoy the therapeutic calm and relaxation that comes from exploring these unique coastal ecosystems.
Three Native U.S. Mangrove Species
Types of Mangroves
In the United States, mangroves are most common along the coast of the Florida peninsula, south of Cedar Key on the Gulf Coast and south of Cape Canaveral on the Atlantic coast, and along the coast of southern Texas, south of Port Aransas. There are three types of mangrove species native to the United States: red, black and white. All three species can filter out salt from seawater as it enters their roots.
But in the Gulf and Southeastern United States, mangroves are on the move. In particular, black mangroves, which are the least sensitive to lower temperatures, are increasingly found north of their historic range. In recent years, they have been found on the barrier islands of Apalachicola Bay and Mississippi Sound, in extreme southern Louisiana, and on the mid- and upper-Texas coast. This northward movement is most likely enabled by climate change causing a decrease in freeze events that damage or kill mangroves at their northernmost locations.
How TNC Protects Mangroves
Conserving mangrove forests requires a forward-thinking approach that will envision the challenges ahead and create a framework for how to overcome them. To understand how mangroves have expanded across the Gulf and Atlantic coasts, TNC scientists, working with Northeastern University and the U.S. Geological Survey, created an created the online Mangrove Explorer Mapping Tool depicting the current (as of 2021) distribution of mangroves in the southeastern U.S. To better plan for the anticipated changes associated with mangrove expansion, the team applied a model using known climate and ecological relations, recent climate data and future climate projections to estimate changes in mangrove distribution and coastal wetland vegetation in the southeastern United States. They quantified potential changes in mangrove presence, mangrove relative abundance, coastal wetland vegetation height and coastal wetland vegetation above-ground biomass.
Given the critical importance of mangroves, this online mapping tool shows where mangroves are located today and models that predict where they will expand across the Gulf and Atlantic coasts in the future. The Mangrove Explorer can help predict future changes in mangrove distribution and provide insight into the potential implications of those changes to people and nature. Funding for this project was provided by the National Academies of Sciences Gulf Research Program.
Specifically targeted to coastal managers, the Mangrove Explorer provides cutting-edge science-based maps to inform decision making across multiple sectors ranging from conservation planning to hazard mitigation.
Resources
Explore the resources below to learn more about mangrove conservation and stewardship and to download useful tools to aid in your conservation efforts.
- Mangrove Explorer Tool
- Projected changes in mangrove distribution and vegetation structure under climate change in the southeastern United States August 16, 2024
- The impacts of mangrove range expansion on wetland ecosystem services in the southeastern United States: Current understanding, knowledge gaps, and emerging research needs January 31,2022
To learn more about mangrove conservation, download our reports below.
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Ensuring a Future with Mangroves
A handbook for mangrove engagement, restoration and management in the Gulf and the SE Atlantic. Download the Handbook
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Hurricane Damages to Mangrove Forests and Post-Storm Restoration Techniques
The first of three reports to be released by TNC in collaboration with our partners, this report is part of a year-long project aimed at assessing the feasibility for a mangrove insurance project in the Gulf and the Caribbean. Download the Report
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Mapping Mangroves Manual
A manual features GIS mapping and monitoring techniques for mangroves. Download the Report
Contact
For more information about TNC's work in this area or to suggest additional resource links for this region, please contact Christine Shepard, director of science, TNC Gulf Program.
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