Geographical
and Ecological Focus
Southeastern Arizona is renowned for its exceptional biodiversity, ranking among the richest in the Western Hemisphere.
Seven ecoregions overlap in this area, which contributes to its rich and unique biodiversity. The term ecoregion refers to areas with similar ecosystems, as well as type, quality, and quantity of environmental resources. In Southern Arizona, we can find the following ecoregions: Sonoran Basin and Range, the Madrean Archipelago, and the Chihuahuan Basin and Range. In Northern Arizona, the ecoregions include the Mojave Basin and Range, the Colorado Plateaus, the Arizona-New Mexico Plateau, and the Arizona-New Mexico Mountains. These regions bring an interesting mix of climates, elevations, and species.
This region also is also dotted with Sky Islands—isolated mountain ranges that rise from desert lowlands—creating a mosaic of habitats that support a vast array of species.
The Madrean Sky Islands
This region is located in the Madrean Sky Islands or Madrean Archipelago, a unique and incredibly diverse region expanding from northwestern Mexico into the southwestern United States. This region is one of the world’s most biologically diverse temperate areas with isolated mountain ranges, known as “islands” and surrounded by deserts and grasslands. Furthermore, this region is known for its unique ecological and cultural richness, making its conservation, restoration, and protection essential.
The region is also covered by springs, creeks, wetlands, and marshes that support plants like sycamores and cottonwoods, along with other species that depend on them.
When it comes to wildlife, the Sky Islands are home to over 80 species of mammals, including jaguars, Mexican gray wolves, ocelots, black bears, beavers, bats, and coatimundis. It is also a vital migration corridor for birds and butterflies, thanks to waterways like the San Pedro River, Cienega Creek, and the Santa Cruz River.
For instance, the Chiricahua Mountains alone host over 400 bird species, including many that are rare or absent elsewhere in the United States. This diversity is attributed to the convergence of multiple biogeographic zones, allowing for a unique blend of flora and fauna.
Additionally, the nearby Chihuahuan Desert is recognized as the most biologically diverse desert in the Western Hemisphere, home to a remarkable variety of plant and animal life.
These examples underscore southeastern Arizona's status as a biodiversity hotspot, offering critical habitats for a multitude of species and serving as a vital corridor for migratory wildlife.
References
Griffith, G.E., Omernik, J.M., Johnson, C.B., and Turner, D.S., 2014, Ecoregions of Arizona (poster): U.S. Geological Survey Open-File Report 2014–1141, with map, scale 1:1,325,000, http://dx.doi.org/10.3133/ofr20141141.
López-Hoffman, L., & Quijada-Mascareñas, A. (2012). Madrean Sky Islands, North America. In J. A. Hilty, C. C. Chester, & M. S. Cross (Eds.), Climate and Conservation. Island Press/Center for Resource Economics. https://doi.org/10.5822/978-1-61091-203-7_17
Strom, S. E. (2024). Forging a Sustainable Southwest: the Power of Collaborative Conservation. University of Arizona Press.