THE ECOLOGY OF AN ENDEMIC AND RARE SPECIE S WITH A FRAGMENTED DISTRIBUTION - CYCLAMEN BALEARLCUM WILLK IN FRANCE

The ecology of rare species is largely unknown. Though informations on the ecology of these species, as well as on their biological traits a nd genetics, are necessary to achieve their conservation. Ecology of C yclamen balearicum Willk. in France was studied by analysing a set of 40 phyto-ecological releves. This late successional species grows in F rance under a mediterranean climate, in shaded situations, in sites ch aracterized by moderate to copious precipitations (650 to 1800 mm per year) and frosts occurring each year commonly (mean of the minima of t he coldest month from - 0,7 degrees C to + 0,7 degrees C), steep relie f and north aspect, stony calcareous soils with blocks, important cove r of evergreen woody plants, small number of therophytes, very Low hum an impact. Quercus ilex L. and Buxus sempervirens L. are very often th e dominant tree and shrub species In these sites. Two kinds of habitat were distinguished. They mainly differ on geomorphological features, vegetation height and floristic composition. Ecological patterns were discussed in relation with decisive factors such as shade, frost and d rainage, and human impacts. The farm or rarity showed by the species i n France was discussed according to the criteria proposed by Rabinowit z. As numerous endemic species with narrow distribution, Cyclamen bale aricum Willk. has in France a restricted habitat, but where it grows i t is sometimes abundant.