GERMINATION AND SEEDLING DYNAMICS OF ARBUTUS-UNEDO AND ERICA-ARBOREA ON CORSICA

Analysis of the seedling distribution of Erica arborea and Arbutus unedo, two dominant plant species in the Corsican maquis, and of three tree species (Pinus mesogeensis, Quercus ilex and Quercus pubescens) with which they compete in a mosaic of successional habitats, has enabled the determination of the successional position of the two ericaceous species. Erica arborea and Arbutus unedo are often considered to be pyrophytes, but the distribution pattern of their seedlings, following either abandonment of cultivation or after fire, indicates that fire is unfavourable for their establishment. Field and laboratory studies of the germination of the two ericaceous species indicate that the absence of seedlings following fire is not due to the destruction of seeds by fire but due to the newly created environmental conditions. Erica arborea invades sites abandoned after cultivation and has thus spread widely since the end of the last century. Arbutus unedo, the seeds of which are disseminated in bird droppings, has the ability to establish in denser vegetation, and thus appears to be a mid-successional species.