ECOLOGICAL CHARACTERISTICS AND RARITY OF ENDEMIC PLANTS FROM SOUTHEAST FRANCE AND CORSICA - IMPLICATIONS FOR BIODIVERSITY CONSERVATION

The analysis and comparison of endemic plants in southeast France (215 taxa representing 7.2% of the flora) and in Corsica (240 taxa, 11% of the flora) exhibit similar ecological preferences and life strategies (sensu Grime). Both show a clear altitudinal zonation, a predominance of stress-tolerant taxa and an ability to colonize harsh habitats (wi th low competition and disturbance). The particular characteristics of these endemics primarily reflect the richness, topography and history of the specialized habitats of the regions involved. However, the deg ree of isolation and the intensity of competition probably helps to ex plain the contraction of some endemic species' niches in southeast Fra nce, and conversely the expansion of these niches in Corsica. The anal ysis of data related to comparable territories in the Mediterranean an d throughout southern Europe, seems to show that. (I) mountain isolati on has generally been more favourable to endemism than insularity; and (2) the degree of endemism often decreases as floristic richness incr eases. Finally, 32% of endemic plants are threatened in Corsica, and 2 8% in southeast France. The low altitude zones are most affected, part icularly coastal areas, rocky grasslands and damp ecosystems, but the risks now extend throughout all sectors due to the increase of human a ctivities. Faced with these major threats, in situ protective action m ust be taken immediately through appropriate management of indigenous populations, and scientific studies undertaken to analyse population v iability. (C) 1997 Elsevier Science Ltd.