Mangroves like their land coastal and their water salty. This tree and shrub family is adapted to spend their lives between land and saltwater, sometimes growing up to 200 feet tall in the process. Mangroves can have their roots in shallow, salty water because they are also exposed to air for part of the day. Their roots use this time above water to sequester oxygen for when they’re submerged. Mangrove roots create some of the most productive ecosystems on Earth, as their intertwined structure provides habitat for sessile creatures like barnacles and creates protective nurseries for juvenile fish. Mangrove roots provide more than habitat though: they trap sediment to stabilize coasts, and bio-filtrate nutrients and pollutants out of the water. These ecosystems are massive carbon sinks, taking in and storing excess carbon dioxide from our atmosphere and water—an important attribute in the face of climate change.
Mangroves capture 14% of the world’s ‘blue carbon’. This is carbon that marine plants sequester in coastal ecosystems, and it makes up more than half of the world’s biological carbon. The trees themselves take in some of the carbon, like their terrestrial cousins, but mangroves are much more successful at carbon sequestration because their roots slow down tidal waters. This function allows organic and inorganic material to accumulate in low-oxygen sediment, thereby slowing decay and storing more carbon. In fact, this carbon may stay in the sediment for thousands of years, keeping it from adding to the greenhouse gases in the atmosphere. These trapped sediments also provide other benefits.
Mangrove’s tangled root systems and trapped sediment prevent coastal erosion and provide a natural barrier that protects coastal inhabitants from storms. This protection is vital for coastal communities, particularly because the people living in these tropical areas are often underprivileged and struggle to recover from major storm damages. These helpful trees also provide local communities with timber for boats and houses, as well as fruit and other natural products. Unfortunately, vital mangrove ecosystems are threatened around the world.
Mangroves are essential components of their ecosystems and helpful to coastal communities, but the land that they need is in high demand. Shrimp aquaculture, palm oil plantations, rice farms, and tourist developments are all highly profitable coastal ventures, and mangroves are cut down to accommodate them. Destroying mangroves has widespread implications; when they are cut down, their ecosystems release massive amounts of carbon into the atmosphere and ocean. A study found that the destruction of mangrove forests globally releases 150 million to 1 billion tons of CO2 annually. More than 35% of the world’s mangrove forests are already gone, and they continue to be cleared at faster rates than other forests. Thankfully, mangrove awareness and protection efforts are starting to take root.
Mangrove management efforts are evolving as their ecosystem services become more widely recognized. Policies that take their benefits into account are being developed to include mangroves as actors in coastal zone management. Similarly, marine protected areas (MPAs) that include mangroves and their coastal ecosystems are being recognized for their increased productivity. Just as MPAs in open waters help the surrounding area thrive, mangroves in MPAs help replenish and protect nearby ecosystems. Currently, about 36% of the world’s mangrove forests are inside protected areas, and you can explore our interactive map on the Atlas of Marine Protection to find MPAs that include these amazing trees.
Beyond policy, active restoration and community involvement campaigns are beneficial for mangrove conservation, and are raising awareness about ecosystem conservation. As we move towards a blue economy that values ocean and coastal ecosystem services, investing in mangrove conservation will likely be a big part of the discussion. Mangroves are vital members of coastal ecosystems and strong allies in the climate change fight, so it is inspiring to see communities, scientists, and policy makers collaborating to save them!