The biology and ecology of lotic microturbellarians

1 More than 200 known species of Microturbellaria occur in running waters world‐wide but discovery of many more is likely. Their population density varies greatly as a function of substratum, productivity, phenology and hydrology. The density may exceed 7 000 individuals m‐2. The number of species in a single small sample may reach 20. 2 Many species appear to have microhabitat or stream section specialisation but community patterns are …