You are not currently logged in.
Access JSTOR through your library or other institution:
The Coexistence of Three Species of Daphnia in the Klostersee
Vol. 45, No. 1 (1980), pp. 117-130
Stable URL: http://www.jstor.org/stable/4216067
Page Count: 14
You can always find the topics here!Topics: Eggs, Clutch size, Species, Animals, Birth rates, Vertical distribution, Chlorophylls, Ratios, Zooplankton, Sunlight
Were these topics helpful?See somethings inaccurate? Let us know!
Select the topics that are inaccurate.
Preview not available
1. In the Klostersee in southern Bavaria three species of Daphnia have coexisted for at least several decades: Daphnia hyalina (H), D. galeata (G) and D. cucullata (C). These three species differ in size and compete for food. 2. All three species show marked seasonal fluctuation of abundance, with H and G dominating during spring and late autumn and C dominating during summer. The fluctuations of H and G are stronger correlated than H and C or G and C. 3. The three species are vertically segregated. C preferes the upper strata, H the lower and G the intermediate. This behaviour favours the smaller species C. On the average (from early spring to late autumn), C develops 1.2 times faster than G and 1.5 times faster than H. 4. H and G show higher clutch sizes than C throughout the year. This advantage however is compensated by the higher speed of development of C during thermally stratified seasons. 5. The egg ratio is influenced by both the age structure of the populations and the clutch size of the gravid females. 6. The clutch size depends mainly on the size of the females. The reaction of clutch size to environmental factors follows with a time lag of approximately D (duration of embryonic development). C and G depend more on meteorological influences than H, which is probably related to the vertical distribution. 7. The importance of the differential vertical distribution and the reaction to environmental stress as well as the impact on the size -- efficiency hypothesis are discussed.
Oecologia © 1980 Springer