DISTRIBUTION AND ECOLOGY OF DESMID ASSEMBLAGES IN PAPUA-NEW-GUINEA

Desmid assemblages are described from some 145 freshwater habitats from Papua New Guinea. By means of a Two Way INdicator SPecies ANalysis five main clusters were recognised, i.e. one from tropical lowlands, one extending from lowlands to medium altitude, one from medium-altitude and two from medium to high-altitude waters. The dominant taxa in all assemblies were cosmopolitan, taxa with a restricted geographical distribution were mostly scarcely present. The number of taxa with an Indo-Malaysian-North-Australian, pantropical and palaeotropical distribution decreased with increasing altitude while Arctic-Alpine taxa were only found in highland waters.