Bryophytes de l'île de La Réunion : diversité, endémicité et conservation

This article aims at updating the checklist of bryophytes of La Réunion Island in relation to the recent ecological and floristic studies realized by the authors. One hundred and twenty three taxa were added within the five last years bringing the total number of infraspecific taxa recorded for the island to 776. These additions are the result of (1) investigations of different habitats on the island (2) ecological studies dealing with the bryophyte vegetation dynamics on lava flows and along altitudinal gradients (3) investigations at the bryophyte herbaria of the National Botanical Garden of Belgium and of the National Muséum of Natural History in Paris (4) personal unpublished data of T. Pócs. This high diversity on a small oceanic island of 2512 km2 can be explained by its subtropical geographic location, the presence of a high altitudinal gradient (up to 3070 m) and a high rainfall regime and a relative short distance to dispersal sources (East Africa, Madagascar). Distribution maps of species richness identify the present hot spots of diversity, as well as centres of endemic taxa on the island. Additionnally, a first state of knowledge is given and a preliminary task list is proposed for the conservation of bryophytes on the island.