Malpai Borderlands

The Malpai is part of the Madrean Region which includes the arid and semi-arid borderlands of the United States and Mexico from California to Texas.

The Malpai consists of steep, narrow mountain ranges separated by grassy, semi-arid plains.

[4] Also within the Malpai Borderlands is the San Bernardino National Wildlife Refuge in Arizona, consisting of 2,309 acres (934 ha).

[5] The terrain of the Malpai Borderlands consist of a series of north-south rending mountain ranges separated by broad, mostly flat valleys.

The Sky Islands have cooler temperatures, receive greater precipitation, and have more diverse and abundant vegetation than the valleys.

[6] Grassland and shrub land make up 87.9 percent of the vegetation in the Madrean region mostly in the valleys and lower elevations of the mountains.

[9] The climate of Animas, New Mexico on the northern edge of the Malpai Borderlands at an elevation of about 4,500 ft (1,400 m) is borderline BW (arid desert) and BS (semi-arid steppe) in the Köppen Classification system.

[11] The mountain ranges rising above the semi-desert lowlands have greater precipitation and lower average temperatures.

Thus, the climate of the higher mountains is substantially different than that of the lowlands with average annual precipitation reaching perhaps 20 in (510 mm).

[12] In 1990 the Nature Conservancy purchased the Gray Ranch, with an area of 502 sq mi (1,300 km2) from a Mexican owner.

As a result in 1993, the Nature Conservancy sold the ranch to the newly created Animas Foundation.

The conditions of the sale prohibited the Foundation from developing the land but permitted continued cattle grazing.