Water availability, protected areas, and natural resources in the Andean desert altiplano

The arid Andes between 18° and 30° South are located in the transition zone between the tropical and westerly circulation belts. Precipitation rates are lower than 150-200 mm/yr. Results from paleoclimatic and isotope hydrologic research suggest that modern recharge of the water resources in this area is very limited, or even below the level of detection. The groundwater resources of today were formed when precipitation rates were greater than at present by a factor of 2.5. Thus, water is a resource that is renewed extremely slowly, or is even non-renewable. The distribution of mountain protected areas along the 7,500 km Andean Cordillera and the extent of the arid diagonal, the zone of extremely low precipitation that crosses from the western flank in southern Ecuador and Peru to the eastern flank in Argentina, are compared. This indicates the very low density of protected areas within the arid diagonal and the potential for endangerment of diversity in this highly sensitive, dynamic, and harsh environment Scientific knowledge about the age and origin of water resources and maps of water protection zones are the basic elements required for decision making. This type of information should help to resolve the growing conflict between the users of water, especially between the expanding mining industry, conservationists, and local communities concerned with the integrity of the fragile mountain ecosystems. Establishment of a series of new protected areas would be a modest but efficient measure for preserving the unique mountain environment and guaranteeing water resources for the benefit of both human development and nature conservation.