Total Area: 1,962,553 acres (794,245 ha)
Ecoregions Represented: Sonoran Xeric Scrub
Partner Organization: Instituto de Medio Ambiente y Desarrollo Sustentable del Estado de Sonora (IMADES)

The Pinacate volcanic region in the Mexican state of Sonora is the most arid state in North America, and the only desert ecosystem in the Parks in Peril program.
		El Pinacate Biosphere Reserve is a narrow strip in northwest Mexico, just south of the U.S. border. This diversity is well represented in a cross section near the eastern end of the reserve from the Gulf of California, through the Sierra El Pinacate, to the international border.
One of the most arid places in North America, the El Pinacate Biosphere Reserve is like nowhere else in the hemisphere. It is composed of two subdivisions of the Sonoran Desert: the Arizona high plateau and the Lower Colorado River Valley. The Lower Colorado River Valley is the most arid and hottest division of the Sonoran Desert ecosystem.

Ecological Significance
El Pinacate is in the heart of the Sonoran Desert, with high summer temperatures, low relative humidity, intense solar radiation, and high evaporation. According to the Mexican Federal Decree for the reserve, El Pinacate harbors three threatened, one endangered, and one “special protection” species of plants; two endangered, 12 threatened, and one “special protection”species of birds; 11 threatened, five rare, five “special protection” species of reptiles and amphibians; and one endangered and two threatened species of fish.

The reserve includes geologic remnants that reflect an active volcanic history including a volcanic shield that is more than 5,000 square kilometers, numerous lava tubes, 10 large craters and more than 400 cinder cones. Surrounding the volcanic shield are the largest active dune fields in North America, with some dunes reaching heights of more than 200 meters. A rare form of dune known as star dunes is found here. This unique dune environment is habitat for a number of endemic plant species as well as endangered species, including the Sonoran pronghorn antelope and the dune chameleon. There are more than 560 species of vascular plants, 40 species of mammals, 200 species of birds, 40 species of reptiles and amphibians, and four species of freshwater fish in the reserve’s unique habitats. The Pinacate Biosphere Reserve is considered by many to be the heart of the Sonoran Desert. Staff from the reserve collaborates with two U.S. protected areas along the Arizona/Sonora border—Organ Pipe National Monument and Cabeza Prieta National Wildlife Refuge. The reserve is a key component of the binational Sonoran Ecoregional Planning Project.

Principal Threats Affecting Biodiversity in the Site

Date of initial threats analysis for site: December 1994 Date of most recent update: October 25, 1999 draft Source of threats analysis presented below: Site Conservation Planning process using 5-S methodology - process not completed and not done with The Nature Conservancy's MOS software
Participants in analysis presented below: Carlos Castillo, Ruben Soto, Haydee Mirannda, Naomi Mendoza, Ana María Soto, Rocio Gama, Victor Quiroga, Angel Quintana, Guadalupe Morales, Victoria Diggins, Heather Huppe

Like most protected areas in Mexico, local people depend on the natural resources of the Pinacate Reserve, resulting in numerous threats to its fragile ecosystems. To plan the conservation efforts, the reserve staff grouped this biodiversity in seven major conservation targets: Biological Dune Communities, Pronghorn antelope, Riparian Ecosystem of the Río Sonoyta, Communitities of the “tinajas” (permanent to semi-permanent water sources in bedrock on volcanic features in washes), Biologic communities of the volcanic shield and granitic mountain peaks, native fish species, and maternal colonies of Sanborne’s long-nosed bat. The main threats to conservation targets include exotic species invasion, devleopment of roads, off-road vehicular traffic, cattle grazing, poaching, and water extraction.