Efectos del fuego sobre un bosquecillo de Polylepis australis (Rosaceae) en las montañas de Córdoba, Argentina

Abstract

Fire is used to transform woodlands into grasslands and to promote the regrowth of grasses to increase their forage value. According to some authors, this use of fire has caused a retraction of Polylepis woodlands to rock outcrops inaccessible to fire, while other authors postulate that their distribution is due to the favorable environment they find on rocks and not due to the influence of fire. We evaluated the relative effects of fire and environment on survival, seed production and growth of Polylepis australis Bitter (Rosaceae). We studied 74 burnt and control individuals during 3.5 years. The presence of rocks had a great influence on the percentage of P. australis that was burnt. In turn, the percent which was burnt was negatively related to survival, seed production and growth in height. Biomass production was highest when they were burnt in intermediate percentages. Rock had no positive effect on the studied variables, except as a protection against fire. Our results suggest that P. australis distribution is at least in part due to fire. For its conservation we suggest fire reduction, restrict high fire risk activities to areas with a high proportion of rock and, when possible, protect individuals exposed to fire with stones.