Lang Sen Wetland Reserve

The sound of wings arrives first. There are only a few at first, then more, then a whole corner of the sky stirs, as if someone had shaken out a giant sheet of cloth over the water. Shrill cries mix with hoarse ones as the birds call to each other across the still marshes. In the dry season, when the water drops low, more than 20,000 waterbirds gather here.

Those wings are heading home to Láng Sen.

Láng Sen is a piece of Đồng Tháp Mười, a vast low-lying basin in the Mekong Delta. Today the reserve lies in two communes, Vĩnh Châu and Tân Hưng. Both now belong to Tây Ninh province. Before the administrative units were reorganized, this land was part of Tân Hưng district, in Long An province.

Two maps show why Láng Sen is so precious. On a map drawn in 1969, the wetland here covered about 10,000 hectares. Then the wetland shrank, patch by patch. Today Láng Sen is the second largest natural area of Đồng Tháp Mười still left. It also keeps the most representative stretch of natural riverside forest in the whole Mekong Delta.

To walk into Láng Sen is to walk into four worlds woven together. There are grasslands that flood with the seasons. When the water rises the grass goes under, and when it falls the green spreads to the horizon. There are open marshes whose water mirrors the clouds. There is melaleuca forest along the river, its leaves casting shadows on the water. And there is mixed forest, where many kinds of trees crowd together, reaching for the sun. Because these four habitats lie side by side, life here is unusually dense.

The numbers add up quickly. There are 331 plant species. There are 161 bird species, and 142 aquatic species. A child learning one name a day would need nearly two years to learn them all. Among them, 14 species are listed in the Vietnam Red Book, which means they are species in need of protection.

The one mentioned most often is the sarus crane. In Vietnamese it is called sếu đầu đỏ, the red-headed crane, a name that already describes how it looks. The cranes feed on năng kim, so the reserve has restored a 70-hectare field of năng kim to give the flocks enough to eat. But the crane is an honored guest. Whether it comes is up to the sky and the season, and no one can book its visit in advance.

Beside the cranes there are painted storks, adjutant storks and even fishing cats. Under the water live the Mekong giant catfish and the giant barb, big fish of the Mekong. Many of these are threatened around the world, such as the sarus crane, the greater adjutant and the Mekong giant catfish.

The world took notice. Ramsar is an international convention for protecting wetlands. On May 22, 2015, the Ramsar Convention listed Láng Sen as a wetland of international importance. It became Ramsar site number 2,227 in the world and the seventh in Vietnam. It covers 4,802 hectares. Láng Sen meets six of the convention's nine criteria.

Long An province had founded the reserve back on January 19, 2004. It was divided into three zones: ecological conservation, commercial melaleuca and biodiversity. The core that the reserve looks after directly is the ecological conservation zone. It covers about 1,971 hectares. Since July 1, 2025, the reserve has come under the Tây Ninh Department of Agriculture and Environment.

Keeping Láng Sen the way it is takes work. Rain falls out of season, droughts set in, and the water supply shifts. The historic droughts of 2016 and 2020 left the flooded fields parched. So the forest keepers store water for the dry season, guard the melaleuca forest against fire and watch the quality of the water. They also keep watch at patrol posts day and night, because illegal fishing and bird hunting still go on, though less with each passing year.

Some newcomers need watching too. The giant mimosa, the armored catfish and the golden apple snail are invasive species. They multiply very fast and take the place of native plants, shrimp and fish. Workers have to track them down and clear them out, season after season.

Alongside the guarding comes the growing. Every year, workers tend and replant 80 hectares of wild rice, and the lotus fields as well. They have also restored 30 hectares of a rice called lúa ma. Native trees are raised from seedlings and planted back. Gáo and cà na trees are among them. So are lộc vừng, bứa and thorny bamboo. In the hatchery, workers breed trê vàng catfish and snakeskin gourami. They also breed two more fish, rô biển and dầy. Each year about 100,000 young fish are released into the water, like giving the fields back their own children.

Láng Sen does not stand alone. The World Wide Fund for Nature and the International Union for Conservation of Nature work with the reserve on several projects. These projects protect biodiversity and help people in the buffer zone live better and adapt to a changing climate. Around the reserve, residents grow lotus for its young shoots and lotus for its seed heads. They also plant floating rice that follows the floodwater. In the flood season, some families raise snakeskin gourami, climbing perch and snakehead fish as well. There are even classes in drawing silk from lotus, pulling fine threads out of the slender stems. Nine community groups still work together, steadily, to protect the natural resources here.

Láng Sen has not been developed for tourism, because roads and buildings for visitors are still few. But that is also why the place is still truly wild. There are no loudspeakers and no crowded food stalls, only sky, water, grass and birds.

As evening comes, the sunlight turns the color of honey on the melaleuca treetops. The marsh lies still as glass, mirroring a wide dome of sky with nothing to block it. Then from far away the sound of wings rises again, wave after wave. Tens of thousands of wings are coming home to one resting place in the heart of Đồng Tháp Mười.