Galiuro Mountains Ecology
Main Source: U.S. Dept. of the Interior Bureau of Land Management, 1998, Muleshoe Ecosystem Management Plan and Environmental Assessment, BLM/AZ/PL-98-024.
In this part of our Galiuros discussion we focus on the Muleshoe Ecosystem, designated as such by agencies of the U.S. Bureau of Land Management (BLM), the Coronado National Forest, the Arizona Game and Fish Department, and The Nature Conservancy (TNC). This part of the Galiuros encompasses major portions of the Redfield, Hot Springs, and Cherry Springs watersheds/corridors, and includes the Redfield Canyon Wilderness and part of the Galiuro Wilderness, all of these areas falling under the compass of the Muleshoe Management Plan:
Geologically, this mountain range contains multitudes, including the "Mid-Tertiary Taphrogeny" episodes of cataclysmic volcanism some 30-25 million years ago, the massive Basin-Range Faulting process beginning 15 million years ago, and the capture of the San Pedro Valley basin by the Gila River system in more recent times. See Saguaro Juniper Geology for a much fuller array of details. The result is a highly faulted, long set of mountain ranges characterized by high, rocky escarpments, narrow, deeply-incised canyons, and extensive but much-dissected tablelands.
This watershed is drained by two major watersheds and one minor one, all three being tributaries of the middle to lower San Pedro River Watershed. The Redfield Canyon Watershed (62 square miles) drains the northern portion of the Muleshoe Ecosystem, the Hot Springs Canyon Watershed (a total of 109 square miles, 62 of which drain the southern part of these mountains) the southern portion, while the much smaller Cherry Spring Watershed (26 square miles) drains the southwestern portion
Along the western face of these mountains, annual rainfall near the San Pedro River averages from 10-12 inches while the higher mountains receive from 16 to more than 20 inches. Along the bajadas below 4,000' elevation here a long finger of Arizona Uplands subdivision of the Sonoran Desert Ecoregion extends southward from the vicinity of the Gila River, ending somewhere south of Cascabel (see the Arizona Uplands link for map and other details) and interdigitating with the Apache Highlands Ecoregion along mountain flanks. At higher elevations, this long mountain system contains stacks of Sky Island Vegetation Zones.