Original paper
Algae, other than diatoms, affecting the density, species richness and diversity of diatom communities in rivers
Elber, Fredy; Schanz, Ferdinand
Archiv für Hydrobiologie Volume 119 Number 1 (1990), p. 1 - 14
51 references
published: Jul 20, 1990
DOI: 10.1127/archiv-hydrobiol/119/1990/1
ArtNo. ESP141011901000, Price: 29.00 €
Abstract
The influence on diatom communities of algae of other groups, including the chrysophyte Hydrurus foetidus, as well as green and blue-green algae, was examined by comparing the algal periphyton of river bottom stones with that of stones imported to the river bed. In spring, Hydrurus foetidus biomasses were higher on these imported stones than on river bottom stones; in contrast, we observed statistically greater densities of green and blue-green algae on river bottom stones during the investigation period. The mass development of Hydrurus on imported stones diminished the densities of diatoms by reducing their growth rates as a consequence of less available light. According to the dynamic equilibrium hypothesis of Huston (1979), a higher diversity was therefore expected on imported stones than on river bottom stones; this was indeed the case. We observed an increase in the species richness, evenness and diversity. If Hydrurus foetidus was absent, the diatom communities on river bottom stones showed higher diversity values than those on imported stones. The much longer exposure time obviously enabled the biological systems to reach a more complex level. In order to avoid undesired effects in future investigations on the structure of diatom communities, we propose to select sampling substrata lacking mass developments of algae other than diatoms.
Keywords
periphyton • chrysophyte • hydrurus foetidus • hypothesis • imported stones