Sian Ka'an. 27/11/03; Quintana Roo; 652,193 ha; 19°30'N 087°37'W. World Heritage Site, UNESCO Biosphere Reserve, Wildlife Protection Area. The site lies on a large karstic plain along a 120km-long barrier reef. Two large, shallow bays surrounded by mangroves, as well as numerous sinkholes or cenotes, are main landmarks in a landscape of tropical deciduous forests. Endemic communities of swamp forests and of petenes, emerging islands of forests protected from saline intrusions, are mostly pristine and of global significance. There is a wealth of flora and fauna, including 320 bird species and 5 Neotropical felines. Endangered species include Green, Loggerhead, Hawksbill and Leatherback turtles, American and Belize Crocodiles Crocodylus acutus and C. moreletii, Baird's Tapir Tapirus bairdii, Jaguar Panthera Onca, Puma Puma concolor, American Manatee Trichechus manatus and Sperm Whales Physeter catodon. Mayan archeological sites have been found in the Reserve. Several tree species are used for wood, and forest products such as thatch palm leaves and resin for chewing gum are extracted. The main problems are due to overfishing, increasing tourism, forest fires and invasive species. There is a management plan in place and several research activities have been undertaken. A community program training locals as tourist guides has started in order to manage tourism beneficially. Ramsar site no. 1329. Most recent RIS information: 2003.