Case Studies: 5. A Case Study of Two Mexican Biosphere Reserves: The Upper Gulf of California/Colorado River Delta and Pinacate/Gran Desierto de Altar Biosphere Reserves

International Conference on Biodiversity and Society
Columbia University Earth Institute
UNESCO
May 22-25, 2001

Thematic Focus

The Sonoran Desert has experienced a sevenfold population increase in the past 50 years — the fastest growth and most massive land conversion in North America's history. At least 60 percent of the native vegetation of the Sonoran Desert has been converted or destroyed, and virtually all of its rivers have been diverted or dried over the past century. The Colorado River used to supply over 50% of the fresh water entering the Sea of Cortez, but by the early '70s, with 20 major dams along its course, it no longer reached the Sea, running dry near the U.S.-Mexico border. The Lower Colorado River now supports 24 federally-listed endangered/threatened fish species and 67 "at risk" fish species.

The Colorado River corridor used to be the largest wetland in the southwest. 100 years ago, river boats sailed the Colorado and Gila Rivers. Since 1973 its extent has fluctuated between 5,800 and 63,000 hectares, depending on rainfall and upstream agricultural practices. Saline agricultural drainage supports the Cienega Santa Clara wetland, the Delta's largest remaining wetland, with the world's largest populations of Yuma clapper rails and desert pupfish. Even though much of the Delta is part of a biosphere reserve, the delta's water requirements are not taken into account in water management and land use planning.

The Upper Gulf of California-Colorado River Delta Case Study (GCCS) will describe the history of the region, the effort to establish it as a biosphere reserve, the threats and challenges the reserve faces today ranging from water loss and habitat conversion to coastal development and narcotrafficking, as well as progress to date on developing a management plan, what management techniques have worked/not worked to date, predictions for the future of the reserve, and recommendations for similar reserves.

Multi-Stakeholder Workshops

The first workshop for the GCCS was held at Biosphere 2 in June 2000. Participants included representatives of the following organizations: Upper Gulf of California/Colorado River Delta Biosphere Reserve, Pinacate/Gran Desierto de Altar Biosphere Reserve, the University of Arizona, Columbia University's Biosphere 2 Center, Estación Mazatlán, Universidad Nacional Autonoma de M»xico, La Ruta de Sonora, the Sonoran Institute (SI), the International Sonoran Desert Alliance (ISDA), Instituto del Medio Ambiente y Desarrollo del Estado de Sonora (IMADES), and the Centro Intercultural de Estudios de Desiertos y Oceanos (CEDO).

A second workshop is planned for December 4 in Puerto Peñasco, Sonora.

Collaborators and Institutional Affiliates

The GCCS is being prepared by Rick Brusca, in collaboration with coauthors from the institutions represented at the June Workshop.