Ecological responses to multiple-scale flow fluctuation in tropical glacier-fed streams

[Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiples International audience Glacier-fed streams display very specific flow regime characterized by a strong temporal variability at various temporal scales due to the complexity of the water sto...

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Bibliographic Details
Main Authors: Cauvy Fraunie, S., Andino, P., Espinosa, R., Jacobsen, D., Dangles, O.
Other Authors: RiverLy - Fonctionnement des hydrosystèmes, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), PONTIFICAL CATHOLIC UNIVERSITY ECUADOR QUITO ECU, Partenaires IRSTEA, Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA)-Institut national de recherche en sciences et technologies pour l'environnement et l'agriculture (IRSTEA), Centre National de la Recherche Scientifique (CNRS), OSLO UNIVERSITY NOR, Université Paul-Valéry - Montpellier 3 (UPVM)
Format: Conference Object
Language:English
Published: HAL CCSD 2018
Subjects:
Online Access:https://hal.inrae.fr/hal-02609336
Description
Summary:[Departement_IRSTEA]Eaux [TR1_IRSTEA]QUASARE [ADD1_IRSTEA]Systèmes aquatiques soumis à des pressions multiples International audience Glacier-fed streams display very specific flow regime characterized by a strong temporal variability at various temporal scales due to the complexity of the water storages and releases by glaciers. However, the acceleration of glacier shrinkage under the ongoing climate change results in a strong alteration of glacier runoff. In particular, we expect an increase in both low and high extreme flow events. In a tropical glacierized catchment, we examined the relationship between flow fluctuation and aquatic community composition from the diurnal to the inter-annual time scales to identify the mechanisms driving the community structure and predict the aquatic biodiversity response to changes in flow regime under global warming. Based on long-term observational studies, we showed that the benthic fauna was highly adapted to the natural flow fluctuation and displayed both resistance and resilience to high-flow events. On the contrary, a 4-year flow manipulation study indicated that the benthic ecosystem was affected by low-flow conditions. Flow reduction induced a rapid shift in invertebrate community composition characterized by an increase in generalist species density while the system required 30 times longer to return to its initial state. Our studies suggested that the increase in frequency of low-flow events might prevent communities to fully recover leading to irreversible shifts. Thus, the reduction in glacier runoff might induce a homogenization of the aquatic fauna in glacierized catchments, leading to a reduction of the remarkable mountain stream biodiversity.