The Bijagós Archipelago of Guinea-Bissau, recently designated a UNESCO World Heritage site, is a remarkable example of nature’s tidal rhythms supporting one of West Africa’s richest coastal ecosystems. With large tidal shifts revealing extensive mudflats and nourishing diverse habitats, the islands are crucial for migrating shorebirds and endangered sea turtles.
- Tides cause up to 7-meter daily changes in island size and habitat availability.
- The archipelago hosts around 870,000 migratory shorebirds annually.
- Poilão Island is a key nesting site for green sea turtles, one of the largest in West Africa.
What happened
The Bijagós Archipelago is distinguished by a powerful tidal regime that causes expansive mudflats and sandflats to appear and disappear twice daily. This unique environmental pattern results in dynamic coastal habitats across 88 islands and islets. In 2025, UNESCO recognized the archipelago as a World Heritage site, highlighting its importance as the only active deltaic archipelago on Africa’s Atlantic coast.
Scientific studies have shown that the region's broad, shallow continental shelf and estuary shape produce some of the highest tidal ranges in West Africa—up to 7 meters. These tides expose rich feeding grounds for migratory shorebirds and facilitate the movement of marine species, including dolphins and manatees, further into the mangrove forests lining the islands.
Why it feels good
The archipelago’s natural rhythm supports an extraordinary diversity of life. Tens of thousands of migratory birds rely on the exposed mudflats to feed on marine worms, mollusks, and small fish, making this area one of the most vital bird habitats along the East Atlantic Flyway. The biodiversity nurtured here fosters a sense of wonder and hope for conservation successes.
For sea turtles, especially the green sea turtle populations on Poilão Island, the beaches offer critical nesting grounds. Witnessing hatchlings undertake their dangerous journey from nest to sea is a poignant reminder of nature’s resilience and the delicate balance of survival in these ecosystems.
What to enjoy or watch next
Nature lovers and conservationists can follow research updates from this UNESCO site to see how protection efforts support the thriving wildlife. Watching the seasonal migrations of birds or the nesting events of sea turtles highlights the interconnectedness of coastal ecosystems and the importance of preserving these habitats.
Satellite imagery and coastal studies, including data from NASA and partners, continue providing insights into how tides shape biodiversity here. Stay engaged with ongoing Earth science reporting to appreciate how such remarkable natural systems function and how their preservation benefits global biodiversity.