The money in mangroves: how our coastal forests save us billions

Mangroves are one of the most financially valuable ecosystems on Earth. They protect us from storms and flooding and provide us with fish and eco-tourism. But we are losing them at an alarming rate right when we need them the most.

mangrove bush
They might not look like much but mangroves are one of the most valuable plants on the planet

Looking at a mangrove it is very hard to imagine it could be worth anything at all. A small skinny tree with its spindly exposed roots propping itself up in sand and saltwater. It is surprising enough that they manage to survive on our tropical coastlines let alone that anything could live among them. Yet mangrove forests are actually one of the most important ocean habitats supporting a diverse abundance of marine life. They are also one of the most valuable ecosystems to humans on the entire planet. The WWF values mangroves at $186 billion a year, which is considered by many experts to be a big underestimate. But they are disappearing from our coastlines right when we now need them the most and leaving us out of pocket. So just how can mangroves be worth so much money? And how can we protect them and ourselves?

Storm protection

One of the most important benefits that humans gain from mangrove forests is protection from storms and flooding. In the tropical regions where mangrove forests are found, human populations are most at risk from extreme weather events such as hurricanes, cyclones and tsunamis. It is hard to imagine but mangroves are actually the best natural defence against these disasters. This is partially due to the tress themselves, but also because of what they do to the ground beneath them. The thick and complex root systems of mangrove forests actually stabilize the sediment they grow in making it much more resilient to erosion. It also makes it much harder for strong winds and surges of water to uproot the mangroves and move through them. As a result winds, storm surges and big waves are all reduced in power when they pass through mangrove forests.

storm protection
This diagram shows how mangroves reduce storm surges by increasing the level of water in front of them and reducing it behind them protecting coastal properties and people

This obviously makes a big difference to the damage that is caused by storms and floods. In a new study, a research group led by the University of California looked in depth at how mangroves helped protect the people of Florida from hurricane Irma in 2017. They did this by using advanced computer models to simulate what would have happened without mangroves on the coastline. This showed that increased flooding would have cost Florida an additional $1.5 billion in damages. It also highlighted that areas with high mangrove coverage had significantly reduced flooding. In total 626,000 people were believed to have been protected from direct flooding. This study shows us just why mangroves are so valuable. If they can save one state $1.5 billion from one single storm, imagine how much money they save across the entire planet in a year.

Nature’s nursery

As well as being a physical barrier that protects human populations. Mangroves also play a big role in providing us with an important resource, food. That is because they are an important habitat for juveniles of almost all tropical marine species. The nutrient rich shallow waters provide vulnerable youngsters with food and shelter from predators which allows them to grow and develop in safety. This directly aids fisheries in these areas by allowing the next generation of commercially viable species to survive without accidentally being caught by fishermen like in the open oceans. But indirectly it also aids fishermen by allowing key ecosystem species like sharks, turtles and rays to do the same. It is hard to put a precise financial value on this benefit but again it is likely to be in the billions globally.

juvenile lemon
A juvenile lemon shark roams the root system of a mangrove forest in the Caribbean

Tangled with tourism

The other big human industry which is propped up by mangroves in tropical regions is eco-tourism. Areas like the Caribbean in particular rely strongly on mangroves for the same reason that fisheries do. Keystone species like sharks, rays, turtles and reef fish are responsible for attracting millions of visitors to the region every year (although the sun and sandy beaches also help). Without mangroves providing a safe space for these species to grow they would struggle to survive in these places. Without them other valuable ecosystems like coral reefs would also fall into decline (or is that further decline). All in all without the mangroves Eco-tourism which is worth millions to local economies would disappear. Unfortunately it is also their role in tourism that is also a big factor in the mangroves disappearance.

A worrying decline

So as we have seen mangroves provide tropical regions with massive long-term financial benefits. Unfortunately in the short term there is one way which mangroves can become much less valuable. That is because mangroves take up a large amount of a ‘vital’ human resource, prime beachfront real estate. With the boom in tourism and human populations in places like the Caribbean and Florida mangrove forests are being uprooted to make way for luxury villas, new towns and gigantic hotel complexes. As well as this the wood from mangrove trees is actually quite valuable due to its unique properties. It is resistant to rot and insects which makes it a prime material for timber and firewood as well as producing high quality wood chip and charcoal. So clearing mangroves can be a very financially lucrative business for some people. For this reason 3.6 billion hectares of mangrove were cleared globally between 1980 and 2005. Currently the loss of mangroves is declining, but is still believed to be around 1% annually.

tourism
A tourist hotel complex overlooks what is left of the mangrove forest it was built on

Increasing in value

The irony of losing so much mangrove coverage over time is that in the future we will potentially be more dependent on it than ever before. The reason for this is twofold. Firstly due to climate change tropical storms like hurricanes are going to become much more frequent and powerful. As we also lose our natural protection to these events the damage will exponentially increase. We are already starting to see this happening now with devastating storms such as Dorian in the Bahamas, where mangroves forests have seriously decreased in size. The second reason is that with an increasing global population food security is more important than ever. With the loss of mangroves the knock-on effects to fisheries is only just starting to be realised. Unfortunately more people also means more places to live which only makes clearing more mangroves seem more likely. All of this means we will start taking a serious financial hit in the future if we are unable to save these precious ecosystems.

How do we protect them?

Mangrove forests are slow growing ecosystems that take many years to fully develop into the complex habitats they are. So whilst re-planting mangroves is a viable solution for the future. In the meantime it is vital to protect those that remain because when they’re gone they won’t be back anytime soon. One way of doing this is through educating people about how much the mangroves are really worth. As we have seen mangrove forests actually save us billions and make us even more. But this is something not many people are aware of particularly in areas of the world where mangroves grow. Unfortunately putting a price tag on the problem is often the best way to make people value a natural resource.

shoots
Given time mangroves will recover but protecting those that remain is more important than ever

However some researchers are starting to push for another approach. A new paper from the mangrove lab at the University of Singapore argues that mangroves could be saved with a flagship species. For most ecosystems on our planet there is often a species that has become synonymous with that location. Such as polar bears in the arctic or lions in the savanna. These species are known as charismatic megafauna and are often used in conservation efforts to help protect their ecosystems. But when I say mangrove the only thing that pops in to your head is well, a spindly tree. But there are lots amazing animals that rely on mangroves who could become their flagship species. As well as marine species such as sharks, turtles and stingrays there are also many terrestrial species that often get overlooked such as tigers and monkeys in Asia. Any of which could become a mangrove’s flagship species.

But regardless of how we do achieve it, we need to start protecting these massively underappreciated spindly wonders. Before we start losing all the valuable benefits we gain from them forever.

 


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