Beyond classic ecological assessment: The use of functional indices to indicate fish assemblages sensitivity to human disturbance in estuaries - INRAE - Institut national de recherche pour l’agriculture, l’alimentation et l’environnement Accéder directement au contenu
Article Dans Une Revue Science of the Total Environment Année : 2018

Beyond classic ecological assessment: The use of functional indices to indicate fish assemblages sensitivity to human disturbance in estuaries

Au-delà de l'évaluation écologique classique : l'utilisation d'indices fonctionnels pour indiquer la sensibilité des assemblages de poissons aux perturbations anthropiques dans les estuaires

Résumé

Assessing ecological health of aquatic ecosystems is crucial in the current context of biodiversity loss to guide and prioritize management actions. Although several fish-based indices were developed to assess the ecological status of estuarine ecosystems, they do not provide guidance on the causal responses of communities to disturbances. The functional trait-based approach provides an understanding of how human disturbance affects the composition of biological and ecological traits in assemblages, as well as their consequences for ecosystem functioning. Here, we evaluate the responses of fish assemblages to human disturbance in 30 French estuaries using several taxonomic and functional indices (e.g. diversity, evenness or redundancy). We tested whether these indices can provide additional information on the human impacts and health of assemblages that are not reflected by the ecological indicator (fish-based index ELFI). Results indicated that high values of local human disturbances were associated to a decrease in fish abundance, decrease in species richness and reduced functional redundancy, whereas taxonomic and functional evenness increased. In contrast, the functional richness remained stable suggesting that the functional traits of species removed by stressors were maintained by more tolerant species. Indeed, we found that the local disturbances mainly resulted in a decrease in the proportions of small benthic species feeding on macro-invertebrates, which were dominant in the studied estuaries. Some functional alterations were detected by the fish-based index, but the decline of functional redundancy was not reflected, highlighting a serious concern for management. Indeed, the abrupt collapse of functional redundancy in response to local disturbances can decrease the ability of assemblages to maintain certain species traits in the face of future environmental disturbance, including climate change. From a management perspective, the application of such functional redundancy measure in monitoring programs can help stakeholders identify sensitive areas where conservation efforts need to be planned.
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Dates et versions

hal-02607510 , version 1 (16-05-2020)

Identifiants

Citer

Nils Teichert, Mario Lepage, Jérémy Lobry. Beyond classic ecological assessment: The use of functional indices to indicate fish assemblages sensitivity to human disturbance in estuaries. Science of the Total Environment, 2018, 639, pp.465-475. ⟨10.1016/j.scitotenv.2018.05.179⟩. ⟨hal-02607510⟩

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