Resilience of a Complex Watershed under Water Variability: A Modeling Study

Abstract

Understanding how socio-ecological systems respond to environmental variability is an important step in promoting system resilience. In this paper, we asked: How do the frequency and amplitude of water availability variation affect both the social-ecological regimes present and how the system transitions between them? How do these transitions differ under flood-prone and drought-prone conditions? We modified a dynamical systems model of a complex watershed to directly link environmental variability to system-level outcomes, specifically the livelihoods present in the system. The model results suggest that flood-prone systems exhibit more drastic regime shift behavior than drought-prone systems, with abrupt shifts from the complete participation to complete abandonment of livelihood sectors. Drought-prone systems appeared to be more sensitive to the amplitude of water variability, whereas flood-prone systems exhibited more complex relationships with amplitude and frequency, with frequency playing a bigger role compared to drought-prone systems. Lower frequency variations with sufficient amplitudes exposed the system to extended periods of environmental hardship, reducing the system’s ability to recover. Our analysis also highlighted the importance of environmental stochasticity: the deterministic version of the model that assumed no stochasticity overestimated system resilience. The model and analysis offer a more systematic framework to investigate the linkages between sustainability of social-ecological systems and environmental variability. This lays the groundwork for future research in systems with significant current or predicted environmental variability due to climate change.