SPACE-TIME HETEROGENEITY IN THE RECOVERY AFTER EXPERIMENTAL BURNING AND CUTTING IN A CISTUS-LAURIFOLIUS SHRUBLAND

Recovery after experimental burning and cutting in a shrubland of Cist us laruifolius in NW Spain has been studied. The community was homogen eous prior to the disturbances, and tended to recover through a proces s of autosuccession. It was tested whether in a small space (two 100 m (2) plots) there was a greater similarity among individual subplots (1 m(2)) in five consecutive years, or among the five subplots considere d in each plot in the same year. By comparing space and time beta dive rsity using analysis of variance, no significant differences were obse rved, which indicates that temporal changes are not of a greater magni tude than space heterogeneity, even on such a small scale. Changes in time are characterized by an increase in cover by woody species, mainl y Cistus laurifolius, or a decrease in the diversity and richness of s pecies. Space heterogeneity (differences between subplots) does not se em to be determined by environmental gradients, since the sampling sur face is very small, and may be due to the effect of some annual or per ennial species, which are not dominant and only appear in some subplot s, probably due to random dispersal.