Arroyos y manantiales de Tanchachín. 02/02/08; San Luis Potosí; 21°50'N 099°08'W. Located in the Huasteca region, southeast of the Sierra Madre Oriental, the system is a source of water and has a great number of streams and springs. It supports a number of fauna species found under national special protection such as the Lithobates berlandieri, Crocodylus moreletii, Buteogallus anthracinus, Myotis nigricans, and Panthera onca which is endangered. The site also supports endemic species at a national level, which are also threatened, such as Ctenosaura pectinata, Pituophis deppei andVireo griseus. Many flora species found in the site are of great importance for the surrounding human communities, such as of Cedrela mexicana (artisanal use and precious woods), Sabal mexicana (domestic use for the construction of roofs), Acacia farnesiana (construction of fences), Quercus oleoides (domestic use as a combustible), Persea americana, Manilkara zapota y Diospyros digyna (as a source of food). The present uses of land are agriculture (mainly sugar cane) and livestock, which are also considered the main threats to this site. Ramsar site no. 1766. Most recent RIS information: 2008.