Freshwater ecosystems in the Andean region face increasing threats from anthropogenic activities, including hydropower development, agriculture, and water supply demands. Hydrological alteration indicators (HAIs) provide a framework for assessing the ecological impacts of flow modifications, yet their application in tropical highland rivers remains limited. This study evaluates the relationship between HAIs and aquatic ecosystem health in the Chinchiná River, Colombia, integrating hydrological, physicochemical, and biological data.
We analyzed 20 years of daily discharge records to quantify flow variability and alterations using The Nature Conservancy’s Indicators of Hydrologic Alteration (IHA) software. Macroinvertebrate communities were assessed as bioindicators, with samples collected upstream and downstream of two major water catchments of the river. Water quality parameters, including dissolved oxygen, nutrients, and pH, were measured to examine their linkages with hydrological changes. Multivariate statistical analyses, such as redundancy analysis (RDA) and non-metric multidimensional scaling (NMDS), were applied to explore ecological responses to hydrological variability.
Preliminary findings indicate that flow modifications have led to shifts in macroinvertebrate assemblages, with a decline in sensitive taxa and an increase in tolerant species. Hydrological alterations, particularly low flows and reduced flood pulses, were closely associated with degraded water quality and decreased biodiversity. Expected results include the identification of key HAI-ecology relationships that will inform environmental flow recommendations.
This research enhances our understanding of the ecological consequences of hydrological alterations in tropical rivers. By providing empirical evidence on the effects of flow modifications, our findings support the development of science-based water management strategies and conservation policies. These insights are crucial for preserving freshwater biodiversity and maintaining ecosystem resilience in Andean river systems facing increasing hydrological pressures.