Although the leggy trees of a mangrove forest seem to have little in common with the clear blue waters of a colorful coral reef, these two ecosystems are closely connected to each other. Mangrove deforestation not only means loss of habitat for mangrove wildlife such as mudskippers, birds, and deer. Mangrove deforestation also affects coral reefs and this wider impact must be understood.
The Extent of Mangrove Deforestation
Twenty percent of the world’s mangrove forests have been lost since 1980, says the January 2008 report “Loss of mangroves alarming” from the Food and Agriculture Organization of the UN (FAO). The report goes on to say that mangrove deforestation is mostly due to shrimp and fish farming, agriculture, pollution, and tourism. Mangroves provide many ecosystem services including protecting the shore from erosion, providing wood and food to humans, and are a home to a wide range of animals.
Where Mangroves and Corals Interact
Mangrove forests and coral reefs do not always occur near each other. However, these two ecosystems are neighbors often enough that important biological and physical interactions have been observed. Places as disparate as Indonesia, Australia, and the Caribbean have mangrove coastlines not far from coral reefs. The placement of mangroves, coral reefs, and the sometimes-intermediary sea grass beds can be seen in the United Nations Environmental Program’s maps “Global Distribution of Coral, Mangrove, and Seagrass Diversity” at the UNEP/GRID-Arendal Site.
Mangroves Home to Baby Reef Fish
The loss of mangrove forests affect reef fish in a very direct way reports John Roach in the February 2004 National Geographic article “Mangroves Are Nurseries for Reef Fish, Study Finds”. Researchers found that coral reefs near mangroves had twice as many fish as those far from mangrove forests. Many fish are born in seagrass beds and live there until they are too big to hide from predators. They then move on to mangroves to grow a bit more before moving on to reefs. In areas without mangroves, the fish move to the reefs when they are smaller and are easier prey for predators. Mangroves are thus important to healthy, abundant reef communities.
Mangrove Loss Leads to Polluted Coral Reefs
The roots of mangrove trees do an important job of keeping the coastline’s soil intact and out of the ocean. Unfortunately, the loss of mangrove forests can lead to silt traveling out to sea. The eroding coastline is bad for land inhabitants, but it also leads to the siltation of coral reefs. This often means death for corals that are smothered by soil. As the FAO notes in its article, mangroves are important in protecting corals from erosion.
Save the Mangroves, Save the Reefs
Mangrove forests provide important ecological services and humans rely on them for a variety of reasons. Mangroves are thus important in and of themselves. However, it is important to take note of the wide-ranging implications of mangrove deforestation. Mangroves and coral reefs are linked together and what affects one will affect the other.
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