Mangrove restoration in Costa Rica

As we continue our journey toward San Diego, we are pursuing our mission of meeting, documenting and helping people who are restoring coastal ecosystems. Now on the Pacific side of Central America, we are making our way up, following the coast from Panama to California. We first stopped in Costa Rica to meet María who is working on a highly successful project of mangrove restoration

This project, based in Cuajiniquil – a little fishing town in the north of Costa Rica – is the perfect illustration of how to make a restoration project successful: by integrating both the local community and experts in order to respond to socio-economic and ecological needs at the same time. 

As with all the other projects of marine ecosystem restoration we meet and document throughout our expedition, you can watch the episode of our web series dedicated to this one. Read the following article to dive deeper into the project and learn more about the methods used, the community engagement and the results obtained. 

This article, although inspired by our visit and discussions with María, is the sole responsibility of the members of Phœnix Expedition.

Going back in time

This story takes place in Cuajiniquil, in the far north of Costa Rica, in the region of Guanacaste. Over there, the coastal environment is dominated by mangrove forests, like in many tropical and subtropical regions.

At the frontier between the ocean and the land, different species of mangrove share the available space, each of them being adapted to different environmental conditions such as important variation in salinity and desiccation created by the continuous movement of the tides.

Multiple tree species are found within the mangrove such as the red mangrove (Rhizophora mangle), another one from the same family (Rhizophora racemosa), the black mangrove (Avicennia germinans) and the white mangrove (Laguncularia racemosa).

(We have actually met and documented a project of mangrove restoration in Martinique, focusing on the red mangrove (Rhizophora mangle), for which you can read the article or watch the episode of our web series dedicated to this project).  

Rhizophora mangle © Phœnix Expedition

Some 80 years ago, seven hectares of the mangrove in Cuajiniquil had been removed in order to create some salt flats.

The process of creating salt flat is pretty straightforward:

1- the mangrove trees are removed, which creates a barren surface. (In the case of this project, the area removed was about the surface area of two to three football fields);

2- the water from the tide flows in;

3- the water remains in the barren area by being prevented to flow back to the ocean with man-made barriers;

4- through the natural process of evaporation, the water disappears and a huge quantity of salt remains on the floor;

5- the salt is then available for harvesting.

However, the business stopped 40 years ago and by a lack of interest, the salt flats were left out. Although the mangrove is a pretty resilient ecosystem and capable of rapid natural regeneration, in this case, the mangrove did not recover. As María and her team were passing through the area throughout the years, waiting and hoping for life to come back by itself, they quickly realised that if they were not doing anything, this destroyed area would remain so for centuries

And so, with the ambition to help the mangrove recover, they decided to start a project of mangrove restoration

Barren area, the white is salt © Phœnix Expedition

The holistic importance of restoring mangroves

Before diving into the process of how the project was led and conducted, let’s understand why restoring the mangrove is important, from biological and ecological perspectives as well as from social and economic ones. 

The mangrove is an ecosystem providing many « services », also called « ecosystem services ».

“Ecosystem services” is a term used to mention the different benefits we – humans – get from the living world. It helps us to relate more to a natural ecosystem by fully appreciating the different levels at which we benefit from it and to better envision the necessity and emergency of protecting and restoring it.

It is important to note that even if we do rely on the mangrove (and other marine and terrestrial ecosystems), it should not always be needed to prove how humans need it as the sole reason to protect and restore it. The fact that we are sharing space on this unique planet with other species (animals, plants and fungi among others) that have been here for longer than us, should be enough of a good reason to protect them, and restore them when we’ve taken over them. However, talking through the concept of ecosystem services is a useful “language”, understood by all and can help decision-making. 

Carbon capture and storage © Phœnix Expedition
Coastal protection by the mangrove © Phœnix Expedition

The mangrove is a wonderful habitat for many terrestrial and marine species and is especially an incredible nursery for many marine species: fish, shells, snails, shrimps… By coming into the shallow waters of the mangrove, marine species can grow and develop, away from bigger predators from the deeper ocean to which they will return later on in their life. Surviving the early and fragile stages of life, they contribute to bigger populations once back in the open ocean, sustaining local harvesting and fisheries (if done at a sustainable rate and with non-destroying methods, of course). 

Mangroves are critical for maintaining the habitability of the Earth and for helping us to alleviate the current climate crisis we are facing, caused by an excessive amount of carbon in the atmosphere. On top of capturing high amounts of carbon through photosynthesis within their biomass (trunks, branches, roots), mangroves store even more carbon below ground, making it one of the most carbon-rich ecosystems on Earth. The soil in which they are found is filled with organic matter such as leaves and branches accumulated through time and is also really low in oxygen which slows down the process of carbon degradation, locking it for a really long period of time. 

At the frontier between the ocean and the land, the mangrove is confronted to the forces coming from the ocean. By absorbing wave action, the mangrove protects the coastal communities against erosion, flooding and storms. Mangrove trees also filter the water that flows in and out of the forest, contributing to cleaner water going back to the ocean. 

In Costa Rica, tourism is one of the main sources of income. People from all over the world are attracted by the rich biodiversity and preservation of natural ecosystems found in this country like nowhere else. As much as walking through the rainforest to observe birds and dense vegetation, walking through the mangrove could be a guided activity provided by local communities who can show and teach about this beautiful ecosystem whilst making a living.

Channel filled with water from the tide © Phœnix Expedition

Regenerating the mangrove with the community

Now that we better understand why it is crucial to restore mangroves that have been degraded, let’s see how we can do so – or let’s see how María and others have been doing so for the last few years.

Gathering the right people and enough money

Before getting hands-on and starting the fieldwork, there are three important things that need to be gathered:

1- Experts who know exactly what needs to be done and how;

2- People who can help with fieldwork;

3- Funds to run the project in the long term.

Experts on mangrove restoration

María Marta Chavarría Diaz is working in the Area de Conservation de Guanacaste as both a researcher and an officer from the government. Her professional titles aside, María is probably one of the most passionate and excited persons we have met during this expedition. Her bubbly attitude is contagious, and there is no doubt about how she managed to gather the right people and funds to make this project happen.

 María has been working with Dr Claudia Maricusa Agraz Hernández from the University of Campeche (Mexico) who is an expert in mangrove restoration. She has been working for years in this field and has been restoring more than 7,000 hectares of mangroves in Mexico. With a team of people from her research group, she came to do some measurements and exploration of the salt flat in order to produce a design for restoring the mangrove, which served as the starting point of the project.

Aerial view from the channels © Phœnix Expedition

Women's power and community engagement

Once the design was created, and the process of restoring the mangrove was well-defined, the project needed hands: hands to help with the fieldwork – digging channels, planting mangroves- and to help with the monitoring of the project. Who could be better suited to help restore a mangrove than the local community that lives next to it and relies on it in the first place? María and her colleagues from the National Park developed a really good relationship with the local people of Cuajiniquil, especially a group of women who have helped with the project from the beginning. 

Having the local women onboard was a necessary step to gain trust and engagement from the rest of the community. Women are considered really important people within families and within the community. If women were trusting María and her colleagues and were ready to contribute to the project, it was more likely than husbands, sons and more people from the town would join the project. On top of that, people who were asked to come and help were taught about the importance of the mangrove and the benefits for their coastal village, whilst also getting paid for their work and efforts. For all these reasons, the community engagement was highly successful and more than 90 people came and joined the project. 

Some of the women involved in the project © María

Funding the project

For running the project in the long term, considering human and non-human costs, funding is critical. This project was entirely funded by the French Government (French Facility for Global Environment), with the administrative support of the Fundación Corcovado in Costa Rica. We – a fully-French crew – were happily surprised to discover that some of our taxes actually go towards that sort of project (and we hope that if you’re French, you’ll be happily surprised too!).

The process of restoring a mangrove

Once experts, people to help and the money are gathered, what comes next? 

How do you revive seven hectares of mangroves, from a barren area saturated with salt to a healthy and productive forest?

They are two ways of restoring mangrove forests, an active and a passive way which we have both described in our previous article about mangrove restoration. 

In the case of the mangrove of Cuajiniquil, the passive method was chosen. In order to restore this mangrove, the hydrology of the area (the way water flows) needed to be restored in the first place. This is exactly what Claudia came up with: a design to improve the movement of the water. By digging channels, the water from the ocean could flow in and out again with the tide. 

The principle is the following: if the water comes back and inundates the previously dry area, salt could be diluted again, new trees could colonise, fish could come back and the whole mangrove forest could start to grow back

For four months, local people, restoration experts and researchers dug channels, starting early in the morning (about 5 am) until midday (or until the sun was unbearable). Little plants of mangrove trees were also planted on the border of the channels in order to sustain the walls and prevent the collapse of the channels.

With people working in sections, little by little, the whole area was transformed and reconnected to the ocean, giving a new opportunity for the mangrove to regenerate.

© Phœnix Expedition
© Phœnix Expedition

A bright future

Successful results for the mangrove

After all this work, magic (also called « life ») happened: water started invading the channels and spilling over the dry area, diluting the salt, allowing fish species to come and grow in the shallow waters of the channels, transporting mangrove propagules naturally and ultimately increasing the natural recruitment of mangrove trees all over the area. 

Since then, Maria and her biomonitoring assistant, Ivannia Hernadez Chaves – and also helped by Claudia who comes to visit from Mexico – have been monitoring the success of the project: measuring the number of recruits for the different mangrove species, crab caves (showing the comeback of the crabs that were previously absent), pH, salinity, oxygen, the temperature of the water, capture and storage of carbon

For example, they have monitored more than 3,000 plants of the black mangrove (Avicennia germinans) and 300 plants of the white mangrove (Langucularia racemes) which have all arrived naturally, established by themselves and have been growing in a healthy way since the hydrology has been restored. 

Even if it is almost impossible to say for sure when the mangrove will be back to a healthy, productive and resilient state, María is hoping that in 15 years, efforts will pay back and the mangrove will be almost fully regenerated. 

Aerial view from the restoration site © Phœnix Expedition

Benefits for the community

Cuajiniquil is a small relatively poor fishing village. Engaging with the local community and integrating them in the process was the best way to both help them become stewards of their local environment (i.e. the mangrove) whilst giving them a source of income. 

The local group of women still comes weekly to the mangrove to help with some of the monitoring, and is planning on creating a tour within the mangrove to show and teach tourists about this ecosystem and how it is being restored. 

After two years of the pandemic, María is going to start again her work with the local children of Cuajiniquil. She is planning some workshops and participatory-monitoring activities (heights of the trees, distribution of the different species etc.) in order for them to realise how important their local environment is.

A bit of hope in times of global emergency

When facing the state of the planet today, considering both the climate and biodiversity crises, as well as the social injustice that is interlinked to them, it is difficult to stay optimistic or to know what to do. But the more projects of this sort we meet throughout the expedition, the more we realise that taking action – on the ground and concrete action that consider both people and the rest of the living world – is the best we can do. 

Even if words do not always reflect our inner feelings and emotions in the face of such a situation, the ones María used give us a true example of how restoring ecosystems is one of the most useful and hopeful things one could do

« In my job, I’ve been doing a lot of things, but doing mangrove restoration is wonderful. We, human beings, have been doing a lot of damage to our planet. So, our planet, in a way, is sick, because we haven’t treated it with respect. So, if I can help, in a way, to restore a little bit, it will help this wonderful planet. That makes me feel so good that I can contribute to something, yes little, but something in such a big mess. »
María, our wonderful host © Phœnix Expedition

Meeting María, Ivannia and some of the local women has been a wonderful experience. We left Costa Rica impressed, touched and filled with knowledge and insights about mangrove restoration. We can only wish the best to this project and to the local community of Cuajiniquil for the future, hoping their efforts will pay back. We are looking forward to seeing this mangrove in a few years, which for sure will be even denser, healthier and more productive than today. 

Watch episode 5 of our web series to discover the mangrove of Cuajiniquil, see the channels that have been dug and the new trees that have appeared, and listen to María about her work.

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