Mangroves are an important part of tropical coastal ecosystems, but you may be asking yourself, what even is a mangrove? Simply put, they are a tree or shrub that lives in saltwater environments along the coast.
But they are so much more than that.
We don’t expect you to be a mangrove-pro. That’s what we’re here for. You’ve already taken the first step in the right direction: You clicked on this blog! Now sit back and relax while we tell you 25 things you may not know about these special terrestrial ecosystems.
Yeah, you read that correctly. These terrestrial ecosystems absorb and store carbon, removing it from the atmosphere and storing it within the plant. The mangroves use the carbon dioxide for their leaves, roots, and branches and once they die, they fall to the seafloor and store the carbon for thousands of years. This buried carbon is referred to as “blue carbon” because it is stored underwater. Researchers state that worldwide, mangroves can sequester more than 28 million tons of carbon EVERY YEAR. Now that’s a ton of carbon…
Just like us Floridians, mangroves enjoy basking in the sun on tropical coastlines. Unfortunately, there’s high competition for that kind of real estate. Mangroves are dozed away for urban development and sandy beaches and are being cleared at a faster rate than tropical rainforests. In the Americas, over one-third of mangroves have already disappeared.
Researchers estimate that collectively, the world’s mangroves provide billions of dollars worth of services to humans. This is achieved through fisheries, providing storm protection, food, improved water quality, protecting the climate, etc. The mangroves provide food, medicines, wood, and other resources as well as sustainable tourism. Mangroves provide an environment for activities such as kayaking and bird-watching which stimulates tourism. However, it is extremely important that tourism is accomplished in a sustainable way, limiting the number of visitors and ensuring the safety of the ecosystem.
“Kayaking through a snake of mangroves in Hopkins”. Image retrieved from unsplash.com courtesy of Aristedes Carrera
Around the world, more than 50 different species of mangroves can be found. These species are very different, and most aren’t even closely related to one another. Mangrove species are distinguished by physical and ecological traits rather than through the plant genus.
Mangroves are located in the tropical and subtropical regions of the world, mostly between latitudes 25° N and 25° S (hence twenty5degrees!). Where mangroves are located is entirely dependent on temperature.
Even though there are more than 50 species of mangroves around the world, only four of those species are found in the United States: red, black, white, and buttonwood. The most well-known mangrove is the red mangrove due to their distinguishable red, tangled roots. The black mangrove is more tree-like, and if you look closely at their leaves, you may see little flakes of salt. Next up, the white mangrove is the smallest of the four species. Unlike the red and black mangroves, white mangroves have no visible aerial roots, however, when they are found growing in oxygen-deprived sediment, the mangroves develop short “peg roots”. Lastly, the buttonwood. This mangrove species gets its name from the button-like look of its flower head and can be found more inland than its fellow mangrove species.
More than a quarter of the world’s mangroves are found in Indonesia with approximately 3 million hectares of mangrove forest growing along its coastline. Asia is home to 75% of all mangrove ecosystems in the world.
Because of their dense root systems, mangroves provide an ideal hiding place for small animals. An abundance of species relies on mangrove habitats for protection whether they live directly on the roots or within the roots as a hideout. Many swimming species will use the mangroves as nursery habitat, spending the early stages of life within the safety of the roots before venturing off into the ocean later on. These species include many fish, sea turtles, and even juvenile sharks.
Mangroves are home to more than just marine life; they also make a great habitat for land species. Many birds nest in the branches and canopy of the trees, and small insects feed and nest in the twigs. Some types of insects have even evolved to look like mangrove twigs and leaves! The shallow waters and exposed mudflats within the mangrove system are ideal for birds and crocodiles.
The complicated network of roots allows for mangroves to filter and trap sediments and pollutants. The roots are able to hold onto these elements and absorb nutrients from runoff, reducing erosion while improving the surrounding water quality.
Mangrove ecosystems are rich in biodiversity. As previously mentioned, mangroves are able to absorb nutrients from runoff, filtering the surrounding water, forming a nutrient-rich habitat. By providing nesting and breeding for fish, birds, sea turtles, and other animals, mangroves are able to host a diverse array of species. This is especially important as human activity continues to cause a decline in biodiversity.
There are some trees that can tolerate some degrees of salinity, but mangroves are the only tree species in the world that can survive in the harsh conditions in which they do. Mangroves are able to survive being submerged in saltwater, unlike any other tree species. Why is that…? Keep reading!
Mangroves have evolved over time specifically to endure these harsh conditions that are fatal to other species. Mangroves are able to grow in soils with twice the salinity of ocean water. Root adaptations have made it possible for these trees to live in oxygen-poor sediments along with the shoreline and salt excretion adaptations enable mangroves to survive in, well, salt.
Their complex root systems trap river and land sediment which slows down erosion and protects the coastline. The aerial root system slows down the water flow which settles the sediment and causes it to accrete as opposed to eroding.
The complex root system of the mangroves. Image retrieved from unsplash.com courtesy of Hayden Dunsel.
Mangroves not only protect the shoreline from erosion, but they also protect the coast against natural disasters such as thunderstorms, hurricanes, and tsunamis. Every 330 feet of mangrove forest can reduce wave height by up to 66% by acting as an obstacle that slows down the water flow and wave energy as the water flows through their tangled roots.
The spread of shrimp farming around the world has detrimental effects on mangrove ecosystems. The mangrove forest gets cleared to make way for the farmed shrimp production.
Their “seeds” are alive! They are already seedlings when they drop from the tree. Vivipary reproduction is one of the many adaptations that have increased the mangroves’ chance for survival. After mangroves flowers are pollinated, a produced seed germinates into seedlings right away. These seedlings are called propagules and they fall off the tree and are swept away by the ocean current, allowing them to grow in a new area away from their parent to avoid competition.
Mangroves provide an important feeding ground for an abundance of different species. Some organisms eat their leaves directly while other organisms, such as decomposers, wait for the decaying debris of the leaves when they fall to the ground. The smaller fish in the ecosystem feed on the crabs and shrimp which become food for the wading birds and larger species who take shelter in the roots.
In many parts of the world, mangroves are harvested for water-resistant wood and the trees have been used in building houses and furniture. Tannins can be extracted from the bark and the leaves can be used in teas and medicine.
In Florida, you’ll find hives near the mangroves as beekeepers use their nectar in honey production. Black and white mangroves produce a flower every summer that bees use to make honey. How sweet is that!
Mangroves play a crucial role in the survival of coral reefs, which are declining at a high rate due to warming waters. As seen on National Geographic, the rise in temperature causes fatal bleaching in the reefs but in areas where mangroves are present, coral is found to survive better under the protection of the roots and higher water quality.
They protect us, they battle climate change, and they feed us?! #TeamMangroves.
When mangroves are cut down and cleared, more greenhouse gases are created than when the rainforests are cleared. A lot of conservation efforts are centered around the rainforests, but these efforts should also focus on mangroves!
Mangroves are part of the shoreline and prevent erosion. According to conservation.org, when they are damaged or removed, it’s not as simple as just replanting the trees. The land starts to erode and the incoming tide, no longer managed by the mangrove roots, reshapes the shore.
The Florida Department of Environmental Protection (FDEP) enacted the Mangrove Trimming and Preservation Act in 1996. This Act bans the use of chemicals that are fatal or harmful to the trees and it makes it impossible to move or interrupt mangroves without a legal permit.
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