Experimental Studies of the Role of Fire in Restoring and Maintaining Arid Grasslands

摘要

Historical writings, old photographs and paintings and paleo-ecological studies document changes typical of desertification (e.g. increases in woody vegetation and declines in grasses) throughout the arid regions of the southwest within the past 150 years (Hastings and Turner 1965, Cook and Reeves 1976, Grover and Music 1990, Bahre 1991). Data from long-term ecological studies and remote sensing indicate that these changes have continued, and in some cases accelerated, in the last 25 years. These increases in woody vegetation have two fundamental implications for fire dynamics in the southwest; 1) they can either increase fuel availability and fire intensity, or 2) they can reduce fine fuels and retard fire spread. Either scenario seriously disrupts the historical fire regime. While fire and grazing have been a long-term concern for land managers in the southwest, and some good comparative studies exist, there are no replicated, long-term landscape studies of fire and its interaction with herbivory.