Alto Golfo de California Biosphere Reserve is a UNESCO Biosphere Reserve located in the state of Sonora in extreme northwestern Mexico. Thee 1,652,110 hectares reserve comprises the El Pinacate y Gran Desierto reserve and the Bahia Adair on the Gulf of California border. Geological volcanic formations with craters, dunes, oasis and beacheā¦Alto Golfo de California Biosphere Reserve is a UNESCO Biosphere Reserve located in the state of Sonora in extreme northwestern Mexico. Thee 1,652,110 hectares reserve comprises the El Pinacate y Gran Desierto reserve and the Bahia Adair on the Gulf of California border. Geological volcanic formations with craters, dunes, oasis and beaches, and the diversity of plant associations determine its special landscape. The reserve was established in 1993 by the President of Mexico as Reserva de la Biosfera del Alto Golfo de California y Delta del Río Colorado and extended in 1995.