The Pinaleño (or Graham) Mountains are one of a group of isolated mountain ranges that are located between the larger, more contiguous Rocky Mountains to the north, and the Sierra Madre Mountains to the south. These isolated ranges are often referred to as "Sky Islands" or "Mountain Islands" because they are surrounded by 'seas' of desert and desert grassland. The Pinaleños are the tallest of these ranges; the tallest peak, Mt Graham (or High Peak as it is locally known), reaches an elevation of 3267m (10,720 ft.). This range also has some of the steepest terrain of the sky islands due to the narrow base of the range and the relatively low elevation of the surrounding deserts.
The sky islands are important facets in the biogeography of the southwest deserts. In many ways they represent a landlocked version of an oceanic island archipelago. Due to the position of this terrestrial archipelago, the flora and fauna of the sky islands are a mix of species from the southern Madrean and the northern Petran (Rocky Mountain) assemblages. Past climate changes, particularly during the Pleistocene glaciations, alternately allowed some species to colonize these mountains and then isolated them. For the populations of many species found on the sky islands, the desert habitats currently surrounding the mountain ranges is an impenetrable barrier. They are completely isolated from other populations of their species, and have been for many thousands of years.
For a detailed list of species occuring within the Pinaleno Mountains please click one of the following links: Vegetation, Mammals, Birds, or Herptiles.
This site is maintained by the Mt. Graham Biology Program - The University of Arizona.
If you have any questions or comments please email us at:RSMP@ag.arizona.edu