We could give you a thousand reasons to protect mangroves - for starters, more than 1500 plants and animals rely on them - but for this article, we will focus on our top 5.
What are mangroves?
Mangroves are a tropical/subtropical plant, found along coastlines, in estuaries, and on riverbanks. They like a warm climate, low-oxygen soil, and slow-moving waters. Ideally, the water should be a mix of salt and freshwater, with different species preferring different ratios of the two.
There are around 80 different species of mangroves around the world. Some have the appearance of shrubs, while others look more like small trees. Across the species though, you can usually recognise mangroves by their intricate root systems, as you can see in the examples below.
Although Mangrove loss has slowed over the past decade, an important amount of global mangrove coverage has already been lost: 5,245 km2 or 3.4% between 1996 and 2020.
We have got a lot of work to do to protect and restore mangroves, so, back to our top 5 explainer of why the world needs them.
1. Mangroves sequester carbon
Mangroves have incredible carbon storage potential. In fact, they store an estimated 5 times as much organic carbon per hectare as tropical rainforests (Donato et al., 2011).
Their secret weapon for carbon storage? Their intricate, complex underground root system.
These roots grow deep into the marshy banks of rivers, slowing down the surrounding flow of water and enabling the sediment to settle around them.
A proportion of this sediment is organic and contains CO2. Since the oxygen levels are usually very low where sediment settles, organic sediment is buried and stored rather than left to decay, preventing the greenhouse gases from being released into the atmosphere.
This process means that mangroves not only absorb emissions via photosynthesis as they grow, but also store carbon around their roots faster than the majority of other tree species on our planet.
2. Mangroves protect against coastal erosion
On top of their carbon sink role, all the sediment that mangroves capture eventually turns into big natural sand bags, which helps to slow down - and even rewind - coastal erosion.
According to the Global Mangrove Alliance’s 2022 report, these plants:
Prevent over $65 billion worth of storm related property damages.
Reduce flood risk for approximately 15 million people every year.
Pretty incredible stuff!
3. Mangroves clean and filter water before it gets to the ocean
Mangroves don’t just protect the shoreline from erosion, they also help protect ocean ecosystems from excess sediment runoffs coming from the shorelines.
Without mangroves, a lot more sediment can be transported into coastal waters.
Once in the ocean, with no complex structure to help it settle, this sediment causes a host of problems:
It can smother coral or seagrass, blocking out sunlight needed for photosynthesis.
It can make the ocean water cloudy, again, blocking sunlight.
It can even kill reefs if the sediment contains chemical run-off from farming activities.
Aside from all the marine life that reefs and seagrass meadows contain, these ecosystems are a big help in coastal protection, reducing waves’ power before they reach the shore: another factor making coastlines with mangroves less prone to erosion.
4. Mangroves provide habitat for a wealth of biodiversity
As we mentioned right at the beginning, mangroves house an absolute wealth of plant and animal life, supporting more than 1500 species. These range from small crustaceans, fish, and birds, to land mammals.
Since mangrove roots slow the flow of passing water, they create a perfect feeding spot for animals at the bottom of the food chain: crabs, shrimps, molluscs and so on.
This then turns into a breeding ground for these smaller species, which then provides a feeding ground for animals higher up the food chain, all the way to people. Thanks to this abundance of food and their calm waters, many larger ocean fish also use mangroves as nurseries.
5. Mangroves provide livelihoods and food for people
Millions of people around the world rely on mangroves for their food and livelihoods, especially fishing communities. Without the nursery space mangroves provide, fish numbers can rapidly decline, especially when combined with overfishing.
By protecting and restoring mangroves, we are also making sure that the people who rely on them can continue to make a living.
The Global Mangrove Alliance states that their global goal of restoring half of an 8,183 km2 area by 2030 could benefit 1 million small-scale fishers and countless communities.
If you want to know more about mangroves, keep an eye out for more blogs in the future. There is a lot more we want to share about these coastal ecosystems, but for now, send us a message with any questions.
Have a look at our mangrove reforestation projects in Kenya, Nigeria, Madagascar and Pakistan to learn more about each site or to get involved with funding them.