“…Stable isotopes studies in the tropics have frequently been constrained by numerous limitations, such as site remoteness, accessibility disruptions during extreme weather, interrupted monitoring (i.e., lack of consistent long-term time series), insufficient local funding, and a variety of socio-economic and political challenges (Landholm et al, 2019;Lee et al, 2019). The latter, in large degree, limits the reliability and robustness of temporal and spatial isotopic assessments (Sánchez- Murillo and Durán-Quesada, 2019). Beyond the lack of scientific information, factors such as rapid population growth, abrupt land use changes (i.e., agricultural, urban development, and mining land expansion), and a large dependency on groundwater exploitation are severely affecting water security and sustainability (Barrow, 2016;Hund et al, 2018;Roberts et al, 2018) across the tropics.…”