Presa de Atlangatepec. 02/02/09; Tlaxcala; 1,200 ha; 19°33'39"N 098°10'49"W. This dam has a great diversity of flora and fauna, with 87 registered species of birds associated with wetlands. During the winter the species diversity increases by thousands of ducks and other waterfowl species such as Pintail (Anas acuta), Gadwall (Anas strepera), American Wigeon (Anas americana), the Northern Shoveler (Anas clypeata), the Mexican Duck (Anas diazi), the Blue-winged Teal (Anas discors), among others. The site is also home to species listed nationally as threatened, such as the Mexican Duck (Anas diazi, endemic to Mexico), the American Bittern (Botaurus lentiginosus) and the Tiger Salamander (Ambystoma tigrinum). The site is important for groundwater recharge and flood control, and it also retains, retrieves, and removes excess nutrients and pollutants. Adverse factors include changes in land use by opening land for agriculture and livestock, leading to a process of soil degradation due to mismanagement. The main land use is fishing. Ramsar Site no. 1986. Most recent RIS information: 2011.