A view of the lower Arid Lands Ecology Reserve before demolition. The ALE Reserve is a 120-square-mile area of native shrub steppe vegetation that lives on the eastern flank of Rattlesnake Mountain. The site has historical significance for the Tribal Nations and was once used as a buffer zone for anti-aircraft defense missions for the U. S. Army. The site was closed to public access in the early 1940s.