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Population dynamics of Daphnia rosea in a small eutrophic pond
Author(s) -
Shei Ping,
Iwakuma Toshio
Publication year - 1988
Publication title -
ecological research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.628
H-Index - 68
eISSN - 1440-1703
pISSN - 0912-3814
DOI - 10.1007/bf02348587
Subject(s) - biology , cladocera , population density , eutrophication , brood , predation , population , daphnia , ecology , phytoplankton , ceriodaphnia dubia , zooplankton , density dependence , branchiopoda , zoology , nutrient , demography , sociology
The population dynamics of Daphnia rosea were studied in a small, eutrophic fish‐free pond during November 1986–November 1987. D. rosea showed two density peaks in 1987, a high peak in spring and a slightly lower one in autumn, but they disappeared in mid‐ and late summer when a smaller cladoceran, Ceriodaphnia reticulata , dominated. The rapid decline in density of D. rosea in mid‐May and the low density in June/July were preceded by or coincided with a period of increased male density, the appearance of ephippial females, smaller body length of adult females, decreased brood size, and increased frequency of empty brood chambers, all of which indicate a worsening food situation. The rapid density decline of D. rosea in mid‐May was considered attributable neither to increasing water temperature, nor predation by the dipteran Chaoborus flavicans , but to insufficient food conditions for the maintenance of stable reproduction. Although edible phytoplankton was abundant in June/July, the general food situation was not suitable for D. rosea due to blooms of the large‐celled dinoflagellate, Ceratium hirundinella , which probably inhibited the feeding activity of D. rosea . The C. hirundinella blooms might also be important for the shift of the dominant herbivore from the larger D. rosea to the smaller Ceriodaphnia reticulata in August/September.