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Competition between Brachionus calyciflorus Pallas and Brachionus patulus (Müller) (Rotifera) in relation to algal food concentration and initial population density

Competition between Brachionus calyciflorus Pallas and Brachionus patulus (Müller) (Rotifera) in... Competitive laboratory experiments between Brachionus calyciflorus and B. patulus were conducted at low (1×106 cells ml−1) and high (3×106 cells ml−1) densities of Chlorella vulgaris and four initial inoculation densities (numerically, 100% B. calyciflorus; 75% B. calyciflorus + 25% B. patulus; 50% each of the two species; 25% B. calyciflorus + 75% B. patulus and 100% B. patulus). Population densities were enumerated and the medium was changed daily for 20 days. B. patulus was a superior competitor in low food density regardless of inoculation density. At high food density, B. calyciflorus showed higher population growth in the first week but thereafter was outcompeted by B. patulus regardless of initial density. When grown alone, B. calyciflorus reached peak abundances (mean ± standard error) of 31±3 and 81±7 individuals ml−1 at low and high food densities, respectively. The corresponding values for B. patulus were 130±2 and 306±13. The adverse effects of B. patulus on the peak abundances of B. calyciflorus were higher at low food concentration. Data on egg ratios (eggs female−1) revealed an inverse relation with population abundance of both tested rotifer species. Our results indicated that the rate of population increase of a species was not a good indicator of its competitive ability. Instead, the ability to reproduce under continuously diminishing food resources (until a threshold level) was responsible for the competitive edge of B. patulus over B. calyciflorus. This was further influenced by the relative inoculation densities of the tested rotifer species and the offered food densities. http://www.deepdyve.com/assets/images/DeepDyve-Logo-lg.png Aquatic Ecology Springer Journals

Competition between Brachionus calyciflorus Pallas and Brachionus patulus (Müller) (Rotifera) in relation to algal food concentration and initial population density

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References (34)

Publisher
Springer Journals
Copyright
Copyright © 1999 by Kluwer Academic Publishers
Subject
Life Sciences; Freshwater & Marine Ecology; Ecosystems
ISSN
1386-2588
eISSN
1573-5125
DOI
10.1023/A:1009912816400
Publisher site
See Article on Publisher Site

Abstract

Competitive laboratory experiments between Brachionus calyciflorus and B. patulus were conducted at low (1×106 cells ml−1) and high (3×106 cells ml−1) densities of Chlorella vulgaris and four initial inoculation densities (numerically, 100% B. calyciflorus; 75% B. calyciflorus + 25% B. patulus; 50% each of the two species; 25% B. calyciflorus + 75% B. patulus and 100% B. patulus). Population densities were enumerated and the medium was changed daily for 20 days. B. patulus was a superior competitor in low food density regardless of inoculation density. At high food density, B. calyciflorus showed higher population growth in the first week but thereafter was outcompeted by B. patulus regardless of initial density. When grown alone, B. calyciflorus reached peak abundances (mean ± standard error) of 31±3 and 81±7 individuals ml−1 at low and high food densities, respectively. The corresponding values for B. patulus were 130±2 and 306±13. The adverse effects of B. patulus on the peak abundances of B. calyciflorus were higher at low food concentration. Data on egg ratios (eggs female−1) revealed an inverse relation with population abundance of both tested rotifer species. Our results indicated that the rate of population increase of a species was not a good indicator of its competitive ability. Instead, the ability to reproduce under continuously diminishing food resources (until a threshold level) was responsible for the competitive edge of B. patulus over B. calyciflorus. This was further influenced by the relative inoculation densities of the tested rotifer species and the offered food densities.

Journal

Aquatic EcologySpringer Journals

Published: Oct 2, 2004

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