Bibliothèque Électronique Lac Saint-Pierre

Oligotrophication from wetland epuration alters the riverine trophic network and carrying capacity for fish

Hudon, C. et Cattaneo, A. et Tourville Poirier, A.-M. et Brodeur, P. et Dumont, P. et Mailhot, Y. et Amyot, J.P. et Despatie, S.-P. et de Lafontaine, Y. (2012). Oligotrophication from wetland epuration alters the riverine trophic network and carrying capacity for fish. Aquatic Sciences , 74 . p. 495-511. DOI: 10.1007/s00027-011-0243-2.

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Résumé

Submerged aquatic vegetation (SAV) constitutes a major component of fish habitat, providing support for epiphytes and invertebrates as well as shelter from pre dators. The effects of wetland epuration from a mesotrophic to a nearly oligotrophic state were examined over a 15 km long reach of the St. Lawrence River under the direct influence of major farmland tributaries. We hypothesized that the nutrient-enriched zone would support a higher biomass of SAV, epiphytes, macroinvertebrates and fish than the nitrogen-deficient epurated zone located down- stream of the wetland. Predictions included that the enriched habitat would support a richer fish assemblage, with higher biomass and growth of juvenile yellow perch than found in the epurated zone. Results supported these hypotheses, demonstrating the chain of effects of nutrient reduction on the biomass of SAV (fourfold drop), invertebrate prey (ninefold), small (threefold) and large (1.5-fold) fish between the two zones. In addition to the reduction in SAV biomass, the replacement of filamentous chlorophytes by benthic mats of filamentous cyanobacteria in the epurated zone resulted in a less complex 3-D habitat structure and a low invertebrate availability for fish. Oligotrophication by wetland epuration exerted negative effects on fish habitat quality, food quantity and availability, with an impairment of juvenile perch growth and recruitment. A generalized model of the changes in habitat carrying capacity occurring with epuration (oligotrophication) or eutrophication is pre- sented, with examples of other aquatic systems in which strong linkages between trophic status, SAV, invertebrates and fish productivity were also demonstrated.

Type de document: Article scientifique
Statut du texte intégral: Autre
Mots-clés libres: Oligotrophication, Nutrient enrichment, Wetland epuration, Perch recruitment, Invertebrates, Submerged aquatic vegetation, Benthic cyanobacteria, Fish habitat.
Sujets: 2. Milieu physique > 2.4. Hydrologie
4. Faune > 4.1. Invertébré
4. Faune > 4.2. Poisson
Date de dépôt: 09 août 2016 16:48
Dernière modification: 25 sept. 2016 16:43
URL officiel: ftp://ftp.mern.gouv.qc.ca/Public/Defh/Publications...
URI: http://belsp.uqtr.ca/id/eprint/319

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