El Vizcaíno Biosphere Reserve is Mexico's largest protected area. Ecosystems found within the reserve include arid zones, dunes and a 5 km-wide littoral zone along its 450 km of coast. The reserve also includes three gray whale sanctuaries that were created in 1972: Ojo de Liebre, Guerreo Negro and San Ignacio Bays. In 1993, UNESCO listed "Pinturas Rupestres de la Sierra de San Francisco" and Vizcaíno's Whale Refuge Bays as part of the Man and the Biosphere Program (MAB-UNESCO) because of their exceptional natural and cultural value. In 2004, San Ignacio and Ojo de Liebre Bays were also listed in RAMSAR as Wetlands of International Importance.
Vizcaíno's region is biologically rich; its marine resources are especially important. There are 308 terrestrial and marine vertebrates inhabiting the reserve, not including fish. There are 469 flora species, most of which are shrubs and small trees. There are 39 regionally endemic floral species. In addition to its biological diversity, the reserve includes more than 200 caves with rupestrian paintings and petroglyphs.
El Vizcaíno Reserve is threatened and there is a great risk that in the near future it will fail to protect and maintain its biodiversity. The main threats include agriculture, overuse of groundwater reserves, extensive grazing, illegal fishing, and legal and illegal hunting. Future, potential threats include a mega-tourism/infrastructure project called "Escalera Náutica" or Nautical Ladder, and mining activities.