Atlantic oceanic islands and archipelagos: Physical structures, plant diversity, and affinities of the bryofloras.

We investigated the species richness, endemism, and similarities of the bryofloras on ten islands and archipelagos in the Atlantic Ocean. We address the following questions: 1) How many bryophyte taxa are there on each island and archipelago? 2) Do mosses and liverworts share similar patterns of diversity? 3) What are their taxonomic distribution patterns? 4) How many endemic taxa are found on the islands? 5) Is there a high degree of similarity amost these bryofloras? We encountered 1,498 taxa, 408 genera, and 204 families, with the seven families representing 35% of all species. Over 14% of the bryophytes are African elements, 8% have global distributions, ca. 3% are Macaronesia elements, 13% are endemic, and 62% with other distributions. We present a checklist of 1,498 bryophyte taxa, of which 201 are endemic (13%). Bryophyte richness and diversity differ significantly amongst the ten islands and archipelagos, and their low similarities illustrate their high degrees of heterogeneity.