Algal biodiversity

The relevance of algae to the current debate on global biodiversity is assessed. Algal diversity is considered at the levels of richness of species and of higher taxonomic ranks and as the variety of habitats algae dominate and their functional importance in the processes they mediate. The geographical distribution of algae indicates substantial differences in species richness and degree of endemism in different regions. Coasts with the greatest diversity of algae occur in both temperate and tropical seas. High degrees of endemism in seaweeds seem unrelated to overall species richness. Information is sparse for the microalgae, but for some groups high endemism occurs in regions of low diversity. The potential vulnerability of algae and algal communities and the possible consequences of their depletion or extinction are assessed. There is an urgent need to inventory the world's algae, conserve species in culture collections and genetic stocks in 'seed' banks, as well as to preserve natural communities by protecting sites of phycological importance. Current progress in these endeavours and some inherent problems are discussed and recommendations are made. The current dearth of appropriately trained phycologists is also identified as a major brake on progress, for algal taxonomists are perhaps the most threatened species of all.