Size-dependent habitat choice in Daphnia galeata Sars and size-structured interactions among zooplankton in a subarctic lake (lake Lombola, Norway)
Primicerio, R. (2003). Size-dependent habitat choice in Daphnia galeata Sars and size-structured interactions among zooplankton in a subarctic lake (lake Lombola, Norway). Aquat. Ecol. 37(2): 107-122. https://dx.doi.org/10.1023/A:1023942931825
In: Aquatic Ecology. Springer: Dordrecht; London; Boston. ISSN 1386-2588; e-ISSN 1573-5125, more
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| Keywords |
Aquatic communities > Plankton > Zooplankton
Availability > Food availability
Climatic zones > Polar zones > Arctic zone
Distribution > Geographical distribution > Vertical distribution
Habitat selection
Interactions
Interspecific relationships
Interspecific relationships > Competition
Interspecific relationships > Predation
Norway, Lombola L.
Temporal variations > Periodic variations > Seasonal variations
Water bodies > Inland waters > Lakes > Oligotrophic lakes
Cyclops scutifer Sars G.O., 1863 [WoRMS]; Daphnia galeata G.O. Sars, 1863 [WoRMS]; Keratella cochlearis (Gosse, 1851) [WoRMS]; Synchaeta Ehrenberg, 1832 [WoRMS]
Fresh water |
| Abstract |
Seasonal changes in vertical distribution of Daphnia galeata and other zooplankters were monitored in lake Lombola, Norway (69° 07′ N). Depth-habitat use, availability of edible algae and zooplankton densities were recorded to examine seasonal changes in intensity of competition between Daphnia and the other herbivores in the lake. Early in July, the exephippial generation of Daphnia aggregated near the surface, independently of body-size. In late July, when fish planktivory was expected to increase, the daphnids moved down during the day. In August, as intraspecific competition for food intensified, small and large Daphnia partitioned the water column, with larger individuals staying deeper. In September, Daphnia became dominated by large individuals, edible phytoplankton reached the seasonal minimum, and the vertical distribution of Daphnia gradually stretched out towards the surface. The observations on food availability and zooplankton densities suggest that interspecific competition intensified by the end of July. Species and stages that were most exposed to exploitative and interference competition by Daphnia were those staying deeper, because their vertical distribution overlapped more with the larger, competitively superior daphnids. These susceptible competitors included Keratella cochlearis and Synchaeta, among the rotifers, and nauplii and early copepodite stages of Cyclops scutifer. Depth-habitat use is discussed in relation to copepod development, zooplankton dynamics and predator-mediated coexistence. |
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