A Methodological Approach To Quantify The Effect Of Flow Variability On Aquatic Population Dynamics
Résumé
The scarcity of biotic data versus the continuity of flow data is a first problem to be solve when trying to built a model of response to flow and related anthropogenic manipulations. Biotic - abiotic model building, for impact assessment or management purposes, requires mathematical links between biotic indices values and corresponding habitat conditions. Giving the fact that living species can integrate past habitat conditions in their behavior, correlations with instant habitat flow data from a biotic sampling moment are not adapted. This limit can be overcame developing a computer routine to calculate a series of antecedent Hydrological Indices (HIs) into incremented periods backwards in time from biotic sampling dates. Correlation analysis is used to select significantly related HIs to biotic indices resulting from sporadic surveys at a same location. This method allows to quantify the time of response of the biota and duration of effect of given HIs on this water course biota. We use for the purpose time series for discharge, and when available, water temperature, flow velocity, water depth and repeated surveys for invertebrates and macrophytes.
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