The role of substrate type on benthic diatom assemblages in the Daly and Roper Rivers of the Australian wet-dry tropics

S. A. Townsend and P. A. Gell
Hydrobiologia, 548, 1, 101-115, 2005-10
The selection of one or more river substrata for the collection of benthic diatoms is fundamental to any monitoring or research programme. In the wet/dry tropics of Australia, where the use of benthic diatoms for river health assessment is in its infancy, the comparability of diatom assemblages on river substrata has been assessed. Benthic diatoms were sampled from seven river sites, with a range of ionic chemistries but low nutrient concentrations. A total of 198 taxa were identified, with some taxa common to temperate Australia. Common species were found on all substrata, with sometimes statistically significantly different relative abundances. The principal finding was the similarity of the epilithon and epidendron, which are considered to be indistinguishable. Rock and wood hard substrata can be substituted for one another during field surveys, thereby increasing the number of potential sample sites available for monitoring activities that standardise to a hard substrate.