Postfire Regeneration of a Mediterranean Heathland in Southern Spain

Abstract

Fire is a recurrent disturbance in the vegetation of Mediterranean climate regions. Most of the woody species (16 out of 19) in a Mediterranean heathland community, in the Strait of Gibraltar region of southern Spain, sprouted from subterranean vegetative organs after a wild-fire. Dominant sprouters were the prostrated oak Quercus lusitanica, three gorses, Genista tridens, G. tridentata and Stauracanthus boivinii, and a heath, Erica scoparia. About 100 seedlings m^-2 of 14 woody species were censused in the first three years after fire. The highest density of seedlings was recorded for heather (Calluna vulgaris), a rockrose (Cistus populifolius subsp. major) and a gorse (Genista triacanthos). Woody vegetation covered up to 85% of the soil surface in the third year after fire. At this stager the community was co-dominated by the sprouters Quercus lusitanica (21%), Genista tridentata (21%) and Stauracanthus boivinii (20%), and the seeder Cistus populifolius subsp. major (20%). A total of 52 herbaceous species, many of them (35) perennials, was recorded, showing a temporal change in species composition. The role of fire influencing community diversity and the consequences for the conservation of heathlands in the Strait of Gibraltar region, are discussed.