Mammals of the Quitobaquito Management Area, Organ Pipe Cactus National Monument, Arizona

Petryszyn, Yar; Cockrum, E

The Quitobaquito Management Area (QMA) bordered on the south by the United States - Mexico International Boundary, is in the southwestern part of the Organ Pipe Cactus National Monument. It is an area with several intermittent seeps and permanent springs (Figure 1). In places the seeps and springs result in permanent and semi-permanent pools. These subsurface waters supplement the soil moisture accrued from normal rainfall, and result in spectacular changes in vegetation. The Quitobaquito Management Area and adjacent areas in Sonora, Mexico, appear to be similar to oases of North Africa or the Middle East. Brown et al. (1983) aggregated the water sources in the Management Area into seven units (Table 1). We added to each an estimate of the area showing significant vegetation changes from surrounding areas. Permanent sources of free water are necessary for the existence of certain plants and animals. Among mammals, most bats and all carnivores and large herbivores need such water. In the QMA only Quitobaquito (0.26 hectares) and Williams Spring (3 sq m) provide a dependable water source. Bats are a special case. Some (Leptonycteris and perhaps Macrotus) appear to be able to survive on water obtained from flower nectar and fruits. Others, such as Pipistrellus and various Myotis, can drink from tiny sources of water, even if the water is in a well or mine shaft many feet below the desert surface. Still others, having narrow wings and limited flight maneuverability, require a large open water surface, such as the pond at Quitobaquito, for drinking. The latter group includes various Tadarida and Eumops. Large carnivores and herbivores can survive much of the year on water obtained from food and various temporary pools. In dry seasons, however, they are dependent upon permanent surface water sources. Spring and seep waters that rarely appear as surface pools can supplement water from seasonal runoff and create areas of increased plant growth. Often these are extensive enough to be evident from aerial photographs. Such areas provide "islands" of microhabitat suitable for Peromyscus eremicus, Neotoma albigula and Notiosorex. Three of the seep/spring areas of QMA are large enough to change densities of various rodents. These three, Quitobaquito, Aguajita Spring, and Williams Spring are discussed separately.

Mammals of the Quitobaquito Management Area, Organ Pipe Cactus National Monument, Arizona

Collections