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DEMOGRAPHIC RESPONSES OF A TROPICAL CLADOCERAN TO CADMIUM: EFFECTS OF FOOD SUPPLY AND DENSITY

2002; Wiley; Volume: 12; Issue: 2 Linguagem: Inglês

10.1890/1051-0761(2002)012[0552

1939-5582

Carlos Barata, Donald J. Baird, Amadeu M.V.M. Soares,

Aquatic Invertebrate Ecology and Behavior

Ecological ApplicationsVolume 12, Issue 2 p. 552-564 Article DEMOGRAPHIC RESPONSES OF A TROPICAL CLADOCERAN TO CADMIUM: EFFECTS OF FOOD SUPPLY AND DENSITY Carlos Barata, Carlos Barata Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal Environment Group, Institute of Aquaculture, University of Stirling, Stirling FK9 4LA UK Please direct correspondence to Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, UK. E-mail: cb5@stir.ac.ukSearch for more papers by this authorDonald J. Baird, Donald J. Baird Environment Group, Institute of Aquaculture, University of Stirling, Stirling FK9 4LA UKSearch for more papers by this authorAmadeu M. V. M. Soares, Amadeu M. V. M. Soares Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, PortugalSearch for more papers by this author Carlos Barata, Carlos Barata Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, Portugal Environment Group, Institute of Aquaculture, University of Stirling, Stirling FK9 4LA UK Please direct correspondence to Institute of Aquaculture, University of Stirling, Stirling FK9 4LA, UK. E-mail: cb5@stir.ac.ukSearch for more papers by this authorDonald J. Baird, Donald J. Baird Environment Group, Institute of Aquaculture, University of Stirling, Stirling FK9 4LA UKSearch for more papers by this authorAmadeu M. V. M. Soares, Amadeu M. V. M. Soares Departamento de Biologia, Universidade de Aveiro, Campus de Santiago, 3810-193 Aveiro, PortugalSearch for more papers by this author First published: 01 April 2002 https://doi.org/10.1890/1051-0761(2002)012[0552:DROATC]2.0.CO;2Citations: 39 Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat Abstract Life table response experiments (LTRE) were performed to investigate effects of food supply on density-dependent effects on life history and population responses of the tropical cladoceran Moinodaphnia macleayi to cadmium. Its short life cycle and relatively constant age-specific birth and mortality rates allowed population growth rates (λ) to be accurately estimated from short life table experiments and by using a simplified two-stage demographic model. Decomposition and regression analyses of λ showed that density-dependent effects on population responses to cadmium were modified by food availability through density-dependent effects on mortality and reproductive rate. At moderate food levels (1.8 μg C/mL of Chorella vulgaris) and low densities ( 125 animals/L), the negative effects of cadmium on daily reproduction rates increased with density; hence density promoted the negative effects of cadmium on λ. At low food levels (0.4 μg C/mL of Chorella vulgaris), increasing population density reduced juvenile survival, increasing food per head. Thus adverse effects of cadmium on reproduction, which had the greatest contribution to λ, were buffered by increasing population density. Regression analysis performed on population responses across increasing population density levels and cadmium concentrations showed that at high densities and low food levels ecological compensation will prevent populations at the steady-state equilibrium size from being driven to extinction by toxicity effects at the individual level. Alternatively, at low densities, when food availability is not limiting, exposure to toxic substances can increase extinction probability. These results indicate that risk assessment procedures based on demographic analysis performed at low densities and high food levels may overestimate the ecological risk posed by toxic substances. Citing Literature Volume12, Issue2April 2002Pages 552-564 RelatedInformation