Cat Ba Biosphere Reserve is of outstanding examples representing the ongoing evolution in coastal regions and islands with high diversity of animals and plants on land and in the sea.  Cat Ba Island has formed 07 tropical ecosystem types, including:

• Primary tropical moonsoon forest on the largest limestone island in Vietnam
• Tidal ecosystems
• Coral reef
• Marine lake ecosystem : one third of the world’s marine lakes
• Soft bottom ecosystems
• Cave and grottos ecosystems (esp. dark water cave)
• Mangrove ecosystem