Ever since David Avalos Bonilla was a little boy, he helped his father harvest a mollusk locals call piangua from the nearby mangroves. When he was a child, the tangled roots of the mangrove forest growing in the shallow coastal waters of Costa Rica, home to countless birds, fish and other wildlife were a source of wonder and sometimes danger. During one of their fishing trips, David and his father got stung by an executioner wasp, and on another, he accidentally grabbed a small caiman (an alligator-like reptile) by the snout.
For his small fishing community, this forest was a source of life. We depended heavily on these wetlands, David says, sitting on the porch of his home surrounded by lush vegetation. For generations, villagers cut mangrove wood for charcoal, dyes, construction, firewood and other needs, and over time, large areas of the forest melted away. We thought God created these trees for us to use. But we never did anything to replenish them.
As David grew older, and as he kept educating himself, he couldnt shake the nagging thought about the consequences of this rampant deforestation. One day, I said to my father, Daddy, dont you think that cutting so many mangrove trees is dangerous? We live in a coastal area. If a giant wave comes, the mangroves will stop it. But if we remove them, the wave will come through.
Mangroves forests, which grow along tropical and subtropical shorelines, estuaries and river deltas, support the livelihoods of approximately 2.4 billion people. They also play a crucial role in protecting coastal communities from storms, filtering water and storing significant amounts of carbon. For much of the past century, mangroves have been counted among the fastest-disappearing ecosystems on the planet, primarily due to unsustainable coastal development, overharvesting, pollution and the increasing effects of climate change.

Mangrove forests are a vital lifeline for people living on the coast, says Sinikinesh Beyene Jimma, Chief of the Marine and Coastal Ecosystems Unit at the United Nations Environment Programme (UNEP). In support of the Kunming-Montreal Global Biodiversity Framework, UNEP, in close collaboration with local, regional and global partners, works to restore 30 per cent of degraded marine and coastal ecosystems while promoting the protection and effective management of at least 30 per cent of the worlds ocean.
One example of these efforts is the Golfo Dulce Hammerhead Shark Sanctuary in Costa Rica, where a community-led mangrove restoration project called Misin Tiburn was launched in 2021 with support from UNEP and the International Coral Reef Initiative (ICRI) Small Grants Programme. The project set out to restore degraded mangroves within the sanctuary after decades of deforestation had weakened the entire ecosystem.
At the very beginning, very few people came to work. They were afraid and suspicious, says Javier Rodrguez-Gonzlez, a forest engineer coordinating Misin Tiburn. But we have persisted, and the project has steadily grown and has now become a community association. We have already covered over 68 hectares, and our goal is to reach 80 hectares this year.
Working with Costa Ricas National Wetlands Programme and Sistema Nacional de Areas de Conservacin (SINAC) at the Osa Conservation Area, Misin Tiburn established two mangrove nurseries, planted more than 12,000 seedlings, and trained park rangers and community members in mangrove monitoring. The estimated survival rate of the seedlings has been between 75 and 80 per cent an unusually high number for a mangrove restoration project.
At first, we saw it simply as a job an opportunity to support our families, says David, who joined Misin Tiburn early on. But now, we see it as an act of love, because these trees will grow for our children and grandchildren.
Recent studies, including a UNEP report, indicate that over the past few decades, the rate of mangrove loss has slowed, while natural recovery has increased, allowing regeneration to offset some of the historical decline. Lessons learned from restoration projects around the world show that long-term success depends on removing barriers to natural regeneration, restoring the ecological conditions necessary for the forests to thrive, and empowering local communities to safeguard their native ecosystems.
The areas where we work were deforested decades ago and then taken over by the fern Acrostichum aureum locally, we call it negra forra, Rodrguez-Gonzlez explains. The fern prevents connectivity between the remaining sections of mangrove forest. We cut the fern to clear natural channels, so the forest can thrive.
The Golfo Dulce initiative has demonstrated that although conservation and restoration require time and effort, the results prove worthwhile. Mangrove plants can adapt to various conditions, says Rodrguez-Gonzlez. At times, I feel that our community has learned to adapt in the same way as these trees.