Where the Sky is Born
Inscribed on the World Heritage List in 1987, Sian Ka'an was first recognized as a Biosphere Reserve in 1986. It is the largest protected area in the Mexican Caribbean, encompassing terrestrial and marine environments of high biological diversity with unique geological features. Its location on a partially emerged coastal limestone plain has resulted in unique geological features, such as sinkholes (cenotes) and underground rivers, important for their high biodiversity and species endemism. Its 651,029-ha area encompasses a diversity of coastal and marine environments representative of the Caribbean Sea and the Yucatán Peninsula, including sandy beaches, rocky beaches, sand dunes, mangroves, shallow bays and coral reefs.
Sian Ka'an protects a 110-km portion of the Meso-American Barrier Reef, the second largest in the world, rich in marine biodiversity, including 52 species of reef fishes. On the terrestrial side, as part of the Sian Ka'an-Calakumal connector, it contributes to connectivity across the forested landscape within the Meso-American Biological Corridor. In addition to high floristic diversity and the presence of many endangered mammal species, the Biosphere Reserve supports the second largest community of aquatic birds in Mexico and is a key part of the migratory bird corridor between North and South America (López- Ornat, 1990). There are 346 bird species registered in the reserve, including resident and migratory species (MacKinnon, 1992). With more than 300,000 ha of aquatic environment it supports the largest crocodile habitat found in any of Mexico's protected areas (Lazcano-Barrero, 1990) and is particularly rich in amphibians and reptiles.