[Changes in phytoperiphyton community during seasonal succession: influence of plankton sedimentation and grazing by phytophages--Chironomid larvae].
The investigation of seasonal changes in spatial structure of phytoperiphyton during succession was conducted at the lower reaches of Akulovsky water channel from April to August 2000. At the beginning of succession from April to June dominant forms were chain-forming diatoms and filamentous green algae, sedimented from plankton. Later, at the middle of June under increasing pressure of herbivorous, they were replaced by stretched unicellular diatoms and colonial cyanobacteria. In late June-August, when herbivorous predation was the most intensive, the relative abundance of typical periphytonic forms decreased while that of settled planktonic forms increased. The effect of planktonic algae sedimentation on periphyton composition was evaluated as similarity between phytoperiphyton and phytoplankton communities measured with Chekanovski--Sorensen index. The value of this index tends to decrease with the development of periphyton while showing some relation to intensity of herbivorous pressure. Minimal values of Chekanovski--Sorensen index were under moderate herbivorous density, whereas maximal values were observed in periods of extremely high or low herbivorous density.
Lukin
V B
VB
Department of General Ecology, Biological Faculty, M.V. Lomonosov Moscow State University, Vorob'evy Gory, Moscow 119899, Russia.
D000818:Animals; D002683:Chironomidae / Q000502:physiology*; D056890:Eukaryota / Q000502:physiology*; D019015:Geologic Sediments; D007814:Larva; D010933:Plankton; D011157:Population Dynamics; D012621:Seasons