Where the Térraba and Sierpe Rivers meet the Pacific, they form the largest and most important mangrove ecosystem in Central America — over 30,000 hectares of mangrove forest, yolillo palm swamp, sandy beaches, and river channels, spread across the mouths of both rivers. It was first protected as a Forest Reserve in 1977 and, in 1995, formally designated a Wetland of International Importance under the Ramsar Convention — one of only twelve such sites in Costa Rica.
The Ramsar designation isn't ceremonial. It's an international treaty commitment — Costa Rica agreeing, alongside more than 170 other countries, that a wetland of this ecological significance gets protected as a matter of national and international obligation, not just local policy that can shift with the next administration.
What a Mangrove Actually Does
Where fresh river water meets Pacific saltwater, mangroves create a nursery environment unlike almost anything else on the coast — a sheltered, nutrient-rich habitat where juvenile fish, shrimp, and crab species spend their early life stages before moving out to open water. A meaningful share of the Southern Pacific's coastal and offshore fishery, both commercial and sport, depends on healthy nursery habitat like this existing somewhere upstream. The wetland also functions as a feeding ground and stopover for migratory birds moving along the Pacific flyway, and a resident habitat for several endangered and endemic species found in few other places.
There's a quieter function too: mangrove root systems absorb storm surge and slow flooding in a way that open coastline can't. Land that sits behind an intact wetland like this one is, in a very literal sense, better protected from the water than land that doesn't have one.
Wetland boundaries carry real zoning and setback implications — this is exactly the kind of due diligence question a title search and municipal review are meant to catch before you're under contract (see The Process for how that works). But the flip side is worth knowing too: land adjacent to a protected Ramsar wetland comes with a permanent buffer against exactly the kind of dense development that would otherwise be creeping toward it, and a level of flood resilience that unprotected coastal land simply doesn't have.