A Diverse Desert
Shared by two nations, the Chihuahuan Desert Ecoregion is isolated from adjacent arid regions by two mountain ranges, the Sierra Madre Occidental to the west and the Sierra Madre Oriental to the east. About 9,000 years ago, this area was wetter and the mountain slopes were dominated by forests. As the area became more dry, species experienced isolation, differentiation, and sometimes extinction which led to the unique Chihuahuan flora and fauna of today.
Deserts, by their very name, are seldom regarded as important reservoirs of biological diversity, but some deserts are extraordinarily rich in species, rare plants and animals, specialized habits, and unique biological communities. The Chihuahuan Desert is considered the most diverse desert in the Western Hemisphere and one of the most diverse arid regions in the world. Unfortunately, the Chihuahuan Desert Ecoregion is also one of the most endangered regions in the world. Overgrazing, water depletion and diversion, changes in the fire regime, urbanization, increases in agricultural and resource extraction activities, invasive exotic species, and overcollecting of native plants and animals are among the greatest threats to biodiversity in the Ecoregion.