an extensive contiguous density stratified coastal aquifer, where a fresh water lens formed from meteoric water floats on top of intruding saline water from the coastal margins. The thousands of sinkholes known as cenotes throughout the region provide access to the groundwater system. The cenotes have long been relied on by ancient and contemporary Maya people. Ecology The vegetation and plant communities of the peninsula vary from north to south. The Yucatán dry forests occupy the dry northwestern peninsula, and include dry forests and scrublands and cactus scrub. The Yucatán moist forests occur across the middle and east of the peninsula, and are characterized by semi-deciduous forests where 25 to 50% of the trees lose their leaves during the summer dry season. The Belizian pine forests are found in several enclaves across central Belize. The southernmost portion of the peninsula is in the Petén–Veracruz moist forests ecoregion, an evergreen rain forest. Northern Guatemala (El Petén), Mexico (Campeche and Quintana Roo), and western Belize are still occupied by the largest continuous tracts of tropical rainforest in Central America. However, these forests are suffering extensive deforestation. Mangroves occur along the coast, with the Usumacinta mangroves around the Laguna de Términos in the southwest, the Petenes mangroves along the west coast, Ría Lagartos mangroves along the northern shore of the peninsula, and the Mayan Corridor mangroves and Belizean Coast mangroves to the east along the Caribbean Sea. The Mesoamerican Barrier Reef System is an immense coral barrier reef which stretches over along the eastern coast of the peninsula. Governance The peninsula comprises the Mexican states of Yucatán, Campeche, and Quintana Roo, as well as Guatemala's Petén Department and almost the whole of Belize. Economy In the late historic and early modern eras, the Yucatán Peninsula was largely a cattle ranching, logging, chicle and henequen production area. Since the 1970s, the Yucatán Peninsula has reoriented its economy towards tourism, especially in the Mexican state of Quintana Roo. Aside from tourism, another source of income that is important in the Peninsula is logging as well as chicle industries specifically in Belize. Oil was also found in certain parts of the Yucatán, bringing in more economic opportunities. Once a small fishing village, Cancún in the northeast of the peninsula has grown into a thriving city. The Riviera Maya, which stretches along the east coast of the peninsula between Cancún and Tulum, houses over 50,000 beds. The