Desert bighorn sheep establish two desert areas in southwestern Arizona to help preserve the desert bighorn sheep: Cabeza Prieta National Wildlife Refuge and the Kofa National Wildlife Refuge. In 1941, the San Andres National Wildlife Refuge in New Mexico was added. Desert bighorn sheep populations have trended upward since the 1960s when their population was estimated at 6,700-8,100. The upward trend was caused by conservation measures, including habitat preservation. In 1980, desert bighorn sheep populations were estimated at 8,415-9,040. A state-by-state survey was conducted a few years later and estimated the overall US desert bighorn sheep population at 15,980. The 1993 estimate of
Badain Jaran Desert the dunes also contribute to maintain their fixed state. This rigid structure also allows peaks, cliffs, gullies and even caves to form as a result of water erosion and desertification. The Badain Jaran Desert, like the Tengger Desert which lies to the east (and with which the Badain Jaran Desert is currently merging due to extensive desertification) is about one-half barren, sandy desert and one-half a mixture of solid bedrock and loose gravel. Several small lakes and oases scatter the desert around which limited vegetation is able to grow. The Badain Jaran Desert is well known for its numerous scattered