Assessing patch-scale metrics for macroinvertebrate habitat quality under hydropeaking stress

Hydropeaking, resulIng from intermiLent on-demand hydropower generaIon, is characterized by frequent and unnaturally rapid sub-daily flow fluctuaIons that lead to biodiversity loss and ecosystem degradaIon worldwide. AquaIc macroinvertebrates are parIcularly vulnerable to hydropeaking due to their limited mobility and complex life cycles. This study presents a framework to quanIfy macroinvertebrate habitat quality at the patch scale across a series of hydropeaking events. Using hydromorphological modelling, we constructed a habitat Ime-series with high spaIal (0.5 m) and temporal (10 min) resoluIon. Four metrics were developed to assess macroinvertebrate habitat quality: i) habitat probability; ii) shiXs between habitats; iii) driX risk; and iv) desiccaIon risk. To assess its applicability, we tested how these metrics relate to riverbed structural complexity, a key property for macroinvertebrate communiIes. Results quanIfy and map how hydropeaking affects macroinvertebrate habitat quality, and show that structurally complex areas offer higher habitat probability, reduced driX risk and daily shiXs, but oXen greater desiccaIon risk. By demonstraIng the ecological relevance of the proposed metrics, this study supports promoIng structural complexity as a means to enhance habitat quality, while emphasizing the need for addiIonal, complementary measures to fully miIgate hydropeaking stressors on macroinvertebrates.