Sian Ka'an Biosphere Reserve 🇲🇽 Mexico Yucatan Travel Guide

The Siancan Biosphere Reserve is situated on the Yucatan Peninsula, which is an area of limestone bedrock with very little change in elevation, and no real surface rivers. With an area of 528,000 hectares, it is the largest protected area in the Mexican Caribbean, and unique for its geography and wetlands. The beaches in Siancan are an essential part of this ecosystem. Being a transition zone between land and ocean, they constitute a very important habitat and nesting grounds for many species of wildlife. The reserve rests on the youngest geological segment of the peninsula, having emerged from the sea less than 2 million years ago. Indeed, the marshes are younger than the forests. The park is roughly divided into three parts by tropical forests, wetlands and marine environments. There are three core zones, Muyil in the north, Cayo Culebras in Ascensión Bay, and Guaymil, the largest core area. Most of the human population is concentrated in the fishing villages of Javier Rojo Gómez, Punta Allen and Punta Herrero, with over 1,000 inhabitants. The inhabitants of Punta Allen come mainly from other parts of the state and Yucatan. There are no indigenous groups within the reserve. They are settled in communities around the area. The main economic activity of the area is lobster fishing. Other species captured in the area are moro crab, scalefish and sharks. Consisting of lowland forest, flooded savannas, mangroves, and a portion of the world's second largest coastal barrier reef, the Mesoamerican Barrier Reef, the reserve is home to 800 plant species and provides habitat for 350 species of birds, as well as jaguar, puma, ocelot, spider and howler monkeys, crocodiles and many types of turtles. In 1995 alone, 550 terrestrial and 843 aquatic invertebrate species were observed. The climate is tropical, with summer rains and occasional cyclones. The area is cloudy for 200 days a year, and the mean relative humidity is around 80%. Cyclones strike between June and October, peaking in September. Strong marine tornadoes, or mangueras, also occur between May and October, although their action is limited and brief. Over the past 100 years, there has been an average of one hurricane every eight years. Some 339 bird species have been recorded in Siankan, with about two-thirds breeding inside the reserve. Large brown, with long flat bills and great throat pouches, the brown pelican is one of the most important birds within the park. Due to the great diversity of aquatic habitats, marine and wading birds are well represented. The Siankan Biosphere Reserve is home to a variety of rare and spectacular creatures, including dolphins, manatees, and many species of tropical fish. One group of wild dolphins has made Siankan its permanent home. Between the months of May and August, the beach is host to four different types of endangered turtles, which come to lay their eggs in the soft sand. The green turtle, loraturtle, laoot turtle, and hawksbill turtle, which have lost important nesting areas in other locations throughout the Caribbean. The Siankan Biosphere Reserve was established on January 20, 1986, by presidential decree, and became part of UNESCO's Man and Biosphere Program that same year. The reserve was declared a UNESCO World Heritage Site in 1987. Siankan is a Mayan phrase that can be translated as where the sky is born, or gift from the sky. The reserve is thought to have been inhabited in the pre-classic and classic periods as part of the chieftainships of Cajoal and Huamil. There are 23 known archaeological sites inside the reserve. Human remains, pottery fragments, and other artifacts discovered within the reserve are thought to be up to 2,300 years old. The northernmost section of Siankan contains what is thought to be an ancient trade route through lagoons and mangrove channels between the cities of Tulum and Mujil. Tulum is a pre-Columbian Maya site constructed during the post-classic period of the ancient Maya civilization. The castillo, or castle, which overlooks the coast on the cliff edge, is one of the largest buildings at the Tulum site. The front wall of the castillo has faint drawings of the descending god and columns depicting the plume serpent, Kukulkan, who is introduced to the Maya by the Toltecs. There are traces of fine frescoes inside the two chambers. The 125-kilometer stretch of coastline that runs from the southern edge of the resort town of Cancun through Playa del Carmen in the Mayan ruins of Tulum and ends at the Siankan biosphere is known as the Riviera Maya. Mangroves, savannas, swamps, and marshes are all included within the classification of wetland. The wetland habitat is also home to the Belize crocodile, an American crocodile, which are present along Mexico's coasts. Water plays a vital role in the existence of each of these habitats, whether it be fresh, salty, or brackish. Wetlands line the coast of Siankan, playing an important protective role as a type of buffer between the ocean and the land that can absorb the impact of storms. Wetland areas contain an immense biological diversity and are home to a number of endangered species. Four species of mangrove line the coastal areas of Siankan. The mangrove communities are critical for the survival of many species of plants, fish, insects, reptiles, and birds. The small white heron with its black bill and legs and yellow feet is one of the reserve's most important birds. Among the species of birds found at Siankan is the pink flamingo. Fresh water contained in the Yucatan's underground aquifer carves a way at the limestone above, weakening it and eventually causing it to give way. The result of this phenomenon is a unique habitat known as a cenote, or sinkhole. Many cenotes remain connected with the aquifer and other cenotes through underground passageways. Occasionally, cenotes are found to be completely isolated from other bodies of water and may contain fish and other wildlife that have evolved over time into completely distinct species. The Mayan people believed God lived in a place deep in the jungle. This is a cenote, a waterhole reflecting the sky above like a mirror. It is worshipped as a sacred place and valued as a precious source of water. People would make sacrifices to the cenote and pray for rain during periods of drought. The waters beneath were worshipped. The transparency of the cenote's waters reaches a depth of 50 meters. A mystical world made of countless stalactites greets the eye about 300 meters ahead. At one time, this place was a seabed. The shell fossils indicate its past. Rain eroded the porous limestone layers and formed the stalactite caves. As the Ice Age came to an end, the underground water level together with the sea level rose and the stalactite caves were submerged beneath the water. Many of the mammal species found within Sien Khan reside in the low tropical forest land which is located in the westerly portions of the reserve. The forest contained many hardwood species including Chechem, Chico Zapote, Mahogany, Salam and other precious hardwoods. The environmental importance of these areas is increased by the international demand for hardwood that has put pressure on many countries in the neotropics. The vast estuary system and adjacent reefs enclose the bays and provide shelter for a large number of species of fish. Its algae is also a rich form of food for fish, shellfish and insects, which are in turn part of the food chain for the wading birds. Sien Khan preserves a complex hydrological system of tropical forests, marshes, mangroves and a large barrier reef providing habitat for remarkably rich flora and fauna and many of the region's characteristic terrestrial vertebrates in addition to 23 sites of pre-Hispanic culture.