Identifying Thresholds, Regime Shifts, and Early Warning Signals Using Long-Term Streamflow Data in the Transboundary Rio Grande–Rio Bravo Basin

As the centerpiece of ecosystems and human societies, river basins are complex social–ecological systems (SESs) that depend on natural flow regime hydrologic variability to adapt changes absorb disturbances. Anthropogenic climate change disturbances destabilize systems. Therefore, a resilience question arises: What is carrying capacity basin, i.e., how much disturbance can basin take until system undergoes shift? To answer this question, study aims identify shifts, thresholds, transboundary Rio Grande–Rio Bravo (RGB) using 110 years monthly streamflow data. address research first, gauged (regulated) naturalized data collected; if flows not available, they calculated through naturalization. Second, standardization estimated drought index. Third, shift assessment performed Fisher Index, fourth, nonparametric Mann-Kendall test used assess Sustainable Regime Hypothesis which evaluates shifts alternative regimes. Results demonstrate thresholds surpassed, including early warning signals, occurred in multiple locations basin. The present highlights importance assessing basin; hence, evaluating transitions, identifying signals critical managing for sustainability ecological SESs. Looking ahead, integration theory into water management has potential recognize sustainable at local, regional, international scale.