First contribution to the diatom flora of the Amsterdam Island (TAAF)

Over 90 taxa have been observed in a first study on the terrestrial and freshwater diatoms of the Amsterdam Island, in the southern Indian Ocean. The observed flora shows little resemblance with that of other subtropical islands (especially Mauritius, Reunion), but there are some similarities with that of subantarctic islands. The cluster analysis revealed 4 assemblages, most problably separated by moisture and pH. The Pinnularia borealis assemblage and the Luticola mutica assemblage prefer dry places. The Nitzschia frustulum var. frustulum assemblages is found on wetter places such as an old block house. The last assemblage is characterized by the presence of many acidophilic taxa and is only reported from the peat area on the central mountain of the island.