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
Mu Us Sandyland Mu Us Sandyland The Mu Us Sandy Land (also known as the Maowusu Desert; 毛乌素沙漠/毛烏素沙漠 Máowūsù Shāmò or 毛乌素沙地/毛烏素沙地Máowūsù Shādì) is a desert in Central China. It is crossed by the Great Wall of China at the south-eastern end of the desert. The Mu Us Sandy Land forms the southern portion of the Ordos Desert and part of the Ordos Loop. The Wuding River drains the area, and then flows into the Yellow River. Confusion exists about where the Ordos Desert begins and where the Mu Us Sandy Land ends. The northern portion of the Ordos Desert goes by another