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Individual Growth Rate as a Measure of Competitive Advantages in Cladoceran Crustaceans
Author(s) -
Romanovsky Yuri E.
Publication year - 1984
Publication title -
internationale revue der gesamten hydrobiologie und hydrographie
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.524
H-Index - 52
eISSN - 1522-2632
pISSN - 0020-9309
DOI - 10.1002/iroh.19840690502
Subject(s) - interspecific competition , biology , zooplankton , trophic level , cladocera , ecology , competition (biology) , population , trophic cascade , branchiopoda , crustacean , daphnia , eutrophication , food web , nutrient , demography , sociology
Intra‐ and interspecific competition for food is one of the main factors governing zooplankton community structure and the evolution of the life history of herbivorous zooplankters. Competitive advantage considered as the ability of a whole population or some developmental stages to survive at low food concentrations is related to individual growth rate rather than to the body size of zooplankters as the “size‐efficiency hypothesis” postulates. The slow‐growing individuals have been shown to have the most competitive advantage. The outcome of competition among cladoceran species in predator‐free waterbodies depends on the trophic status of the latter. In oligo‐trophic and mesotrophic waterbodies, small slow‐growing cladocerans are the superior competitors, while large rapid‐growing species dominate in eutrophic waters and can outcompete the small cladocerans. Small rapid‐growing species, which are poor competitors, can temporarily colonize eutrophic waterbodies. Three main types of cladoceran life history represent the compromises between low population mortality during periods of food depletion and high population natality at the abundance of food.