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THE POPULATION DYNAMICS AND PRODUCTION OF DAPHNIA IN CANYON FERRY RESERVOIR, MONTANA 1
Author(s) -
Wright John C.
Publication year - 1965
Publication title -
limnology and oceanography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 197
eISSN - 1939-5590
pISSN - 0024-3590
DOI - 10.4319/lo.1965.10.4.0583
Subject(s) - biology , daphnia galeata , daphnia , population , predation , branchiopoda , zoology , cladocera , ecology , zooplankton , demography , sociology
Birth rates, population change rates, and mortality rates were computed for a population of Daphnia schodleri. Birth rates were significantly correlated with chlorophyll concentration. Rates of population change followed the trend in birth rates except when Leptodora was present. There was a strong correlation between Leptodora and rate of mortality due to predation. A mathematical model, based on chlorophyll concentration, Leptodora density, and a constant death rate, duplicated the general features of the observed population curve of D. schodleri. A comparison was made between birth rates of D. schodleri and D. galeata mendotae. D. galeata mendotae had higher birth rates when lower water temperatures prevailed and D. schodleri when higher water temperatures prevailed. It was suggested that the reversal of reproductive success, unselective predation by Leptodora, and the formation of epihippial eggs prevented the competitive exclusion of one species by the other. Daphnia net production averaged 0.15 g C m -2 day -1 compared to a gross primary production of 1.125 g C m -2 day -1 . Leptodora accounted for a loss of Daphnia net production averaging 0.05 g C m day -1 . The ecological efficiency of Daphnia was 10%.