Author(s): Ignacio Aznar; Alejandro Baladron; Maria D. Bejarano

Linked Author(s):

Keywords: Mesocosms; Hydropeaking; Hydropower operation

Abstract: This study examines how six Iberian riparian woody species respond physiologically to hydropower-induced hydrological fluctuations (i.e., hydropeaking) using a controlled fluvial mesocosm (Greenchannel, UPM). One-year-old saplings of two shrubs and three trees typical from Iberian Península riparian areas were planted across three elevation zones—high (T1), mid (T2), and low (T3)—and compared with optimally irrigated controls (C). The hydropower scenario imposed daily cycles of variable flow, with the lowest terrace (T3) experiencing the highest flooding frequency, longest inundation duration, greatest flow variation rates, and deepest water levels. After three months, δ13C, δ15N, and δ18O were analyzed. Non -parametric comparative tests revealed significant treatment-dependent and species-specific isotopic differences. Plants in T3 generally showed enriched δ18O and δ13C relative to T1, T2, and controls, suggesting stomatal closure, reduced water renewal and enhanced evaporative fractionation. δ15N responses suggested species-specific nutrient acquisition strategies under altered redox condition , though mechanisms could be corroborated by further research on measurement of soil N pools or redox status. Stable isotopes thus provide valuable, but context- dependent, insights into the effects of hydropower-altered hydrology on riparian plant funciton.

DOI: https://doi.org/10.64697/iahr.proc.ise2026.abs.298

Year: 2026