Kalpitiya, Sri Lanka (CNN) On December 26, 2004, a cataclysmic tsunami struck the coasts of countries in South and Southeast Asia.

Sri Lanka was one of the worst affected nations -- the wall of water devastated the island's southern and eastern coasts

However, the tsunami's impact was uneven with some places suffering far more damage than others. Scientists assessing the landscape after the disaster discovered that some areas which emerged relatively unscathed were protected not by sophisticated warning systems or barriers -- but by their ancient mangrove forests

When Sri Lanka was hit by a tsunami in 2004, some areas were protected by mangrove forests.

Sri Lanka saves its mangroves

Mangroves are trees which -- unlike almost all other plants -- thrive in saltwater. Sri Lanka is a mangrove hotspot with 22 species flourishing along its coasts, deltas and lagoons.

In 2015, Sri Lanka announced that it would protect all of its mangroves -- the first country to make that declaration. The tsunami experience wasn't the only factor in the decision. Mangrove forests help to create healthy seas because they act as nurseries for fish, prawns, crabs and other marine animals that breed among the trees' stilt-like roots.

They also play a role in combating the climate crisis because they have carbon-storing superpowers, locking down more carbon than a terrestrial forest the same size.

But the importance of mangroves wasn't always recognized. They typically occupy prime coastal real estate -- as a consequence, two-thirds of the world's mangroves have been lost.

In Sri Lanka, one-third of the mangroves have been uprooted since 1990 to make way for expanding cities, coastal development and shrimp farms, says Anuradha Wickramasinghe -- chair of Sudeesa, a nonprofit that oversees mangrove conservation and replanting projects. "People were only looking at short-term profits," he says. "They destroyed the environment."

Photos: Sri Lanka's incredible wildlife Sri Lanka is one of the world's 34 "biodiversity hotspots," and the country is heavily dependent on its biodiversity for tourism. Pictured, a male peacock puts on a show in the country's Yala National Park. Hide Caption 1 of 10 Photos: Sri Lanka's incredible wildlife There are up to 5,000 elephants left in Sri Lanka. Hide Caption 2 of 10 Photos: Sri Lanka's incredible wildlife Elephants enjoying a stroll and a leafy snack. Hide Caption 3 of 10 Photos: Sri Lanka's incredible wildlife Sri Lankan temple monkeys taking a well deserved rest. Hide Caption 4 of 10 Photos: Sri Lanka's incredible wildlife Sri Lankan leopards each have a unique pattern of spots. Hide Caption 5 of 10 Photos: Sri Lanka's incredible wildlife Sri Lankan spotted deer are important prey for leopards. Hide Caption 6 of 10 Photos: Sri Lanka's incredible wildlife Blue whales -- the largest animals on Earth -- swim in Sri Lankan waters. Hide Caption 7 of 10 Photos: Sri Lanka's incredible wildlife Wild boars in Yala National Park. Hide Caption 8 of 10 Photos: Sri Lanka's incredible wildlife Hikkaduwa is one of the top diving spots on the island thanks to its impressive coral reefs and ship wrecks. Hide Caption 9 of 10 Photos: Sri Lanka's incredible wildlife Tea plantations cloak Sri Lanka's hill country. They occupy much of what was once prime leopard habitat. Hide Caption 10 of 10

Where mangroves were destroyed, fishing yields plummeted from around 20 kilograms (44 lbs) to around four kilograms (nine lbs) a day, says Wickramasinghe. Seafood is the major source of animal protein in the island nation. Fishermen and their families faced starvation, says Wickramasinghe.

The Sri Lankan government took action by partnering with Sudeesa and US-based conservation group Seacology to implement a program of mangrove preservation and replanting that covers 35,000 hectares.

Women lead the way

Jeewanthi Perera is one of Sudeesa's 38,000 volunteers. The 34-year-old lives in Kalpitiya, a small fishing village on the shore of Puttalam Lagoon on Sri Lanka's west coast.

Perera says the mangroves saved her family from a desperate situation.

Her first husband died in 2004. She remarried in 2014, but the relationship did not work out and Perera found herself living as a single mother with no income and four children to raise.

All Sudeesa's volunteer groups are headed by women because "they can influence the men," says Wickramasinghe, adding that in his opinion, women are better at organizing the finances.

Jeewanthi Perera (center) and other volunteers plant mangrove saplings.

Hard at work on Kalpitiya's beach, planting a row of fragile mangrove saplings in gloopy black mud, Perera says the restoration of the mangroves has been pivotal for her.

Alongside its mangrove work, Sudeesa give microloans to women to help them establish small businesses. Perera borrowed 15,000 Sri Lankan rupees ($83) and bought material to make fishing nets. Her eldest son, who is 16, now earns up to 500 rupees ($2.80) a day catching fish, shrimp and crabs, ensuring the family has enough to eat.

"Mangroves are good for us because they help prawns grow" says Perera. "This project is empowering women in this community. I'm proud of what I've done."