U.S. DEPARTMENT OF THE INTERIORBUREAU OF LAND MANAGEMENT
Large elevation gradients (ranging from 600m at the base to 3,000m at the summits) and topographic roughness contribute to the high diversity of species and biotic communities. The ecoregion is located at the intersection of the temperate zone to the north and sub--- tropics to the south where several major desert and forest biotic influences converge, including the Rocky Mountains, Sierra Madre, the piedmont and plains of the western Sierra Madre, Sonoran Desert, and Chihuahuan Desert.
Warm temperatures are a defining characteristic of the region and during dry summer months can climb above 100 degrees F in lower elevations. Annually, the region receives around 12 inches of rain in valley bottoms and up to 30 inches at mountain tops. Precipitation occurs primarily during the summer monsoon and the winter season.
The Madrean Archipelago is home to numerous endemic species such as the Mt Graham red squirrel and Atascosa gemmed grasshopper, species at the edges of their ranges such as the elegant trogon and ocelot, and neotropical species such as coati and coral bean. Biotic communities include montane coniferous forests, oak---pine woodlands, tropical deciduous forest, oak savanna, short-grass prairie, subtropical thornscrub, and subtropical desert. The ecoregion also contains critical riparian and wetland habitats (cienegas, springs) that encompass a very small portion of the land areas but are keystone ecosystems in this arid environment.
A full list and description of conservation elements will be included in the Pre-Assessment Report.
This REA will examine the potential effects of the following change agents. A more complete discussion of change agents will be presented in the Pre-Assessment Report.
Change agents to be addressed in Madrean Archipelago REA are:
Memos and Reports
Madrean Archipelago (MAD) REA Memos and Report PHASE I PHASE II