Fuel control in Mediterranean gorse shrubland: effects on firepronespecies regeneration

摘要

The objective of this work is to evaluate the effects of different fuel-control techniques (clearing and burning) on the vegetation response capacity of shrublands dominated by Ulex parviflorus. The study was made in shrublands dominated by Ulex parviflorus at different stages of development (at 3 and 9 years of age). In the spring of 1994, the fuel-control techniques of clearing and burning were applied to three shrublands of each of the two age groups, in plots of 1000 m2. Four years after treatment application, we measured the specific vegetation cover on each plot by means of the point-transect method. At each point we recorded the presence of the various species at 4 height strata. Structural variables, such as vegetation cover, bare soil, specific richness and Ulex parviflorus cover, were analysed by two-way ANOVA (treatment and age). The highest bare-soil values corresponded to the plots on the 9-year-old burnt shrublands, whereas the brushed plots showed very low bare-soil values due to vegetation remains deposited on the soil surface. The clearing applied to young shrublands proved to be largely ineffective in controlling Ulex parviflorus since many individuals survived the treatment (50 %). Our results suggest that the vegetation response may not depend solely on the different treatments applied; factors such as the shrubland age or the reproductive strategy of the species to be controlled can be of crucial importance in the effectiveness of vegetation control.