EFFECTS OF PRESCRIBED FIRE AND A WILDFIRE ON OAK SAVANNAS IN THE PELONCILLO MOUNTAINS OF THE SOUTHWESTERN BORDERLANDS REGION

Abstract

The Southwestern Borderlands Region of Arizona, New Mexico, and northern Mexico are known for its biological diversity and beauty. The area is characterized by its mountains surrounded by deserts and grasslands. The region contains representative animals and plants from the Rocky Mountains in the north to the Sierra Madre Mountains to the south. Madrean oak woodlands and savannas are common within the area covering millions of acres. Periodic fires caused by lightning or Native American people maintained the grasslands and reduced the encroachment of woody vegetation and the accumulations of woody fuels. However, the role of fire declined after the transcontinental railroad was completed and large herds of cattle were introduced into the area. Fires are still ignited but do not spread throughout the landscape largely because overgrazing caused a decline in herbaceous vegetation which carried fires. Aggressive fire suppression by land managers also contributed to the reduced influence of fire. Public and private land managers are concerned that the lack of fires in the Borderlands Region is to blame for the increase in woody species and the decline in biological diversity and productivity of the grasslands and savannas. The Peloncillo Programmatic Fire Plan was developed by the Coronado National Forest to re-introduce landscape level prescribed and managed fires into Forest Service and Bureau of Land Management lands within the Peloncillo Mountains (Gottfried et al. 2009). One of the issues was whether it was best to burn in the cool-season (November-April) or the warm-season (May-October) because of concerns about potential harm to the threatened New Mexican ridge-nosed rattlesnake (Crotalus willardi obscurus) and the endangered Palmer agave (Agave palmeri). The agave is important because it provides food for the endangered lesser long-nosed bat (Leptonyceris curasoae). The area usually burns during the warm period prior to the monsoon season.