Two-year evaluation of fuelbreaks grazed by livestock in the wildfire prevention program in Andalusia (Spain)

► Tested classification functions are proposed to evaluate grazing in fuelbreaks ► The most adequate field parameters are selected for a streamlined monitoring system ► The influence of fuelbreak characteristics in grazing effectiveness is determined ► High shrub volume is the factor that most clearly reduced grazing success ► Both goat and sheep flocks showed a remarkable capacity to reduce fuel loads. Livestock grazing of fuelbreaks is a silvopastoral practice which is promoted in several Mediterranean regions with the objective of improving wildfire prevention. In the grazed fuelbreak network in Andalusia (Spain), over 2000 ha of fuelbreaks were characterized and grazing in them was evaluated in 2008 and 2009. The grazing evaluation was based on several visual assessments of the utilization rate of vegetation by livestock and the general grazing level observed. These parameters were employed to classify fuelbreaks into four levels of accomplishment of the grazing objectives, both through individual assessments (2008) and with the aid of an automatic procedure based on discriminant analysis (2009). The accuracy of the automatic classification functions for 2009 reached 86%. This value remained high (82%) when only the parameter with the most discriminatory power (the mean general grazing level) and predefined thresholds were employed. Based on these results, a streamlined monitoring system is proposed to evaluate grazing in fuelbreaks. Regarding fuelbreak characteristics, larger shrub volumes were found to negatively affect the accomplishment of grazing objectives. For fuelbreak surface area, distance to animal shelter and mean steepness, the data were non-conclusive. Both goat and sheep flocks demonstrated their effectiveness in reducing fuel loads.